Tag: ownership (page 1 of 3)

Spark the Wonder of Flight

As 2018 quickly becomes an entry in the logbook, I look forward to the New Year. For me 2019 will be a year of connection, growth and change. It is fairly easy to attend aviation events, fill up our tanks with the latest information, technology, and dream of that PC24 in our hangar. Yet it is much harder to actually roll up your sleeves and volunteer at one of these events. I came across this quote on the Internet and it piqued my interest.

As I look back at my calendar I am very encouraged by the countless men and women who gave of themselves, who were available for opportunity to spark the wonder of flight in others. Here is a sampling of the opportunities for fun and volunteerism that I was fortunate to be a part of. Hopefully you will be inspired to take part in events in your part of the country.

In February I flew in formation with a few other Mooneys to Yuma Arizona to attend the 7th annual Gunfighter’s Formation Clinic. 35 airplanes enjoyed the three-day event co-sponsored by the Red Star Pilots Association and the Mooney Caravan both of which are 501(c)3 non-profits.

Gunfighter’s Formation Clinic

This event brings together aviators of all sorts whose goal is to gain the skill and proficiency to fly mere feet away from one another. We were lucky to have my Mooney sister, Pia Bergqvist, the Executive Editor of Flying Magazine join us for the fun, and she wrote a fabulous article on the joys and challenges of formation flight.

The month of April means that things are shaking in Lakeland Florida for Sun ‘n Fun. I was thrilled to be able to present Exiting the Hold: Reaching your Life Goals in the forums and for AOPA. We all know the fabulous events on the schedule at Sun ‘n Fun, but as a credentialed part of the media I was able to see the inner workings of this week-long annual event. I tend to have a bunch of stuff to carry at shows. I was also lucky enough to have rides in a golf cart to and from the parking lot to the event site.

SNF Volunteers Rock

It was during those rides that I got to know many of the dedicated volunteers. It can be easy to overlook the volunteers, but they really are the ones who make the events so special.

The second Saturday of May is Oceano Airport Celebration: Salute to Veterans. This annual event not only highlights the gratitude for those who have served our country, but as well collects needed items for military care packages. Friends of Oceano Airport [FOA] is a 501(c)3 non-profit as well as a proud member of the California Pilots Association. I am happy to serve as the President of FOA.

Oceano Airport Celebration: Military Care Package Donations

Volunteers are the backbone of this community fly-in. Year after year we transform our campground into the event site. The goal is to share our beach-side airport, highlight its benefits, and inspire the love of flight to our community.

The month of June brings Father’s Day and every June for the past 52 years Columbia Airport [O22] in the gold country of California, hosts hundreds of attendees for the Father’s Day Fly-In. Columbia Airport has an airplane-only campground and is within walking distance of the historic downtown [state park, gold mining, pedestrian only]. I have volunteered at the fly-in for about nine years. It is so fun to see the tremendous community involvement. My Mooney Ambassador booth is popular, not only for having an awesome airplane or two on display, but also for the Moo Pool.

Moo Pool at Columbia Father’s Day Fly-In

It is not uncommon to have over 100-degree weather. Taking a dip in the pool is fun for the kids, and I have known a volunteer or two to put their feet in.

It is hard to think about July without plugging in KOSH in our flight planner. This year I made the trip solo in my Mooney with a very newly overhauled engine and a fairly new IFR rating. Wittman Regional Airport becomes home away from home for over 600,000 aviation lovers and 10,000 aircraft. There are upwards of 5000 of volunteers working to ensure that the event is as fun and safe as possible. I have volunteered at OSH in a couple of capacities as a presenter but probably even more fun as a member of the EAA Airventure Concert Band for 8 years.

EAA Airventure Concert Band

The band is made up of members from all across the country and sometimes world, who practice our music independently over the spring and summer. We come together and practice a few times, then perform at the airshow opener and have a concert. Elton Eisele who is also an EAA Departure Briefing Chairman directs the all-volunteer band.

The first ever VNY Prop Park airport event was held in September. California Pilots Association also held their annual meeting at the event.

Van Nuys Airport Prop Park Fly-In

Historic 16-right provided a great backdrop for renowned speakers Rod Machado and Barry Schiff, a movie night featuring 16R and Living in the Age of Airplanes , 99s scholarship pancake breakfast and aircraft displays. The team of volunteers worked tirelessly to make the new event a success.

Later in September I was happy to be able to present Exiting the Hold at the California Capital Airshow. Established in 2004, the California Capital Airshow 501(c)3 plans and operates the exciting, family-friendly annual event designed to honor the Sacramento region’s rich aviation heritage and veterans while using the power and magic of flight to inspire young people. CCA gives back to the community through scholarships charitable group donations and exciting educational youth programming throughout the year.

California Capital Airshow

The steering committee of the airshow works to involve the military GA, and Sacramento communities. The schedule offers something for everyone. There was a night airshow, a dance under the stars; educational forums and the daytime show featured the Blue Angels.

In October the inaugural Central Coast AirFest took place in Santa Maria, CA featuring the Canadian Snow Birds. This event was willed into existence by a dedicated group of volunteers. There was a tremendous amount of community integration and involvement in the two-day event.

Central Coast Airfest featuring the Canadian Snowbirds

The first Saturday in December is always a busy one for us at Oceano Airport. For the past ten years we have held a Toys for Tots event in cooperation with the US Marine Corp Reserves. The satisfaction of knowing that the children in our local area are receiving gifts underneath the tree is fantastic. In addition to toy collection we also had a burger fry that supported our local San Luis Obispo 99s scholarship fund.

Oceano Airport Toys for Tots

The first event for my 2019 calendar is an evening at ACI Jet Center in San Luis Obispo, CA.  I am working with King Schools to present Exiting the Hold: Reaching your Life Goals. We will gather on Thursday February 21st at ACI. Come enjoy this free community event with FAAST team credit, refreshments, as well as cool door prizes. The face-paced multimedia presentation will help you learn the six elements for getting unstuck in life and reaching your goals.

Spark Wonder

As you look toward 2019 I will give you some advice; get involved. Spark the wonder of flight in your community. Volunteer your talents in local, regional or national events. I guarantee two things; you will be tired, and it will be a happy-tired. See you in San Luis.

Jolie Lucas is a Mooney owner, licensed psychotherapist, and instrument rated pilot. Jolie presents aviation seminars around the country including Sun n Fun, EAA Oshkosh and AOPA. Jolie is the Vice President of the California Pilots Association. She is the 2010 AOPA Joseph Crotti Award recipient for GA Advocacy. Email: [email protected] Web: Twitter: Mooney4Me

It’s Baffling

The email from a Cessna T210 owner read:

Suggested baffle holes

The owner of this T210 suggested making some baffle modifications to improve cooling of cylinders #5 and #6 by “giving them more air.” This would NOT have been a good idea, and would almost certainly have made things worse instead of better.

I recently had my engine rebuilt and had a new baffle kit installed. The CHTs for cylinders #5 and #6 are always 20ºF to 30ºF hotter than the rest. During climb the difference gets even bigger. Cylinder #5 and #6 CHTs are very difficult to keep below 400ºF during a climb, even with the cowl flaps open and rich mixture. Should I consider giving them some air? On cylinder #6, why not cut one or more holes in the white aluminum baffle in front of the cylinder? On cylinder #5, why not drill one or more holes in the horizontal aluminum plate located behind the oil cooler?

I replied that cutting holes in the baffles was definitely NOT a good idea, and that doing so would undoubtedly make the cooling problems worse, not better. It was apparent that the T210 owner didn’t understand how the powerplant cooling system in his aircraft works, or what the function of the baffles is. He’s not alone—some A&P mechanics don’t fully understand it, either!

Cooling: then and now

Spirit of St. Louis

Early aircraft engines were ‘velocity cooled’ by passing the slipstream over the finned cylinders. However, this simple approach to cooling is simply not practical for today’s high-performance engines and low-drag airframes.

In the early days of aviation, aircraft designers took a simple approach to the problem of cooling aircraft engines. The engines were mounted with their finned cylinders out in the slipstream and cooled by the horizontal flow of ram air. This design is known as “velocity cooling” and was adequate for cooling the low-compression single-row radial engines of the time.

As engines grew more powerful and multi-row radials and horizontally opposed engines went into service, it became obvious that simple velocity cooling wasn’t up to the job. For one thing, cooling was uneven—front cylinders got a lot more cooling airflow than rear cylinders. For another, sticking all those cylinders out in the breeze created horrendous cooling drag. A better scheme was obviously needed.

That better system was known as “pressure cooling” and is the method used in all modern piston aircraft. Pressure cooling is accomplished by placing a cowling around the engine and using a system of rigid baffles and flexible baffle seals to produce the volume and pattern of cooling airflow necessary to achieve even cooling with minimum drag.

What do baffles do?

Cooling Airflow

The heart of a modern ‘pressure-cooled’ powerplant installation is a set of rigid sheet-metal baffles and flexible baffle seals that, together with the engine cowling, divide the engine compartment into two chambers: a high-pressure area above the engine and a low-pressure area below and behind the engine. Engine cooling depends upon the vertical airflow from the upper chamber to the lower one. Cowl flaps modulate the cooling by regulating the vacuum in the low-pressure chamber.

Our modern piston aircraft are powered by tightly cowled horizontally opposed engines. Inside the cowling, a system of rigid aluminum baffles and flexible baffle seals divide the engine compartment into two chambers: a high-pressure area above the cylinders, and a low-pressure area below the cylinders and behind the engine. Cylinders are cooled by the vertical flow of air from the high-pressure above the engine to the low-pressure below it. Cooling airflow is top-to-bottom, not front-to-back.

The volume of cooling airflow that passes across the cylinders is a function of the pressure differential between the upper (high-pressure) chamber and the lower (low-pressure) chamber of the engine compartment.  This pressure differential is known as “delta-P.” Cowl flaps are often used to modulate the cooling airflow. Opening the cowl flaps reduces the air pressure in the lower chamber, thereby increasing delta-P and consequently the volume of cooling air that passes vertically across the cylinder fins.

It’s important to understand that the pressure differential between the upper and lower chambers is remarkably small: A typical high-performance piston aircraft generally relies on a delta-P of just 6 or 7 inches of water—about 1/4 PSI! Aircraft designers try to keep this delta-P to an absolute minimum, because higher delta-P means higher cooling drag.

…and so what if they don’t?

Baffle Seals

Flexible seals are used to prevent air from escaping through the gaps between the engine-mounted sheet-metal baffles and the cowling. To do their job, they must be oriented so as to curve toward the high-pressure chamber above the engine, so that air pressure pushes them tightly against the cowling.

Because the pressure differential (delta-P) on which engine cooling depends is so very small, even small leaks in the system of baffles and seals can have a serious adverse impact on engine cooling. Any missing, broken, or improperly positioned baffles or seals will degrade engine cooling by providing an alternative path for air to pass from the upper chamber to the lower chamber without flowing vertically across the cylinder cooling fins.  (This is precisely what the effect would have been had the T210 owner cut holes in his baffles, which is why I strongly discouraged the idea.)

Probably the most trouble-prone part of the cooling system is the system of flexible baffle seals. These flexible strips (usually high-temp silicone rubber) are used to seal up the gaps between the sheet metal baffles and the cowling. These gaps are necessary because the baffles move around inside the cowling as the engine rocks on its shock mounts.

To do their job, the seals must curve up and forward into the high-pressure chamber, so that the air pressure differential (delta-P) presses the seals tightly against the cowling. If the seals are permitted to curve away from the high-pressure area—not hard to do when closing up the cowling if you’re not paying close attention—they can blow away from the cowling in-flight and permit large amounts of air to escape without doing any cooling.

I recall some years ago inspecting a Cessna TR182 whose pilots had complained of high CHTs. Upon removing the top engine cowling, I immediately spotted the problem: One of the ignition leads was misrouted and became trapped between the baffle seal and the cowling, preventing the baffle seal from sealing against the cowling. The ignition lead had become severely chafed where it rubbed against the cowling, and an A&P had wrapped the chafed area with electrical tape, but failed to reroute the tape-wrapped lead to keep it away from the baffle seal. Clearly that A&P didn’t understand the importance of an air-tight seal between the baffle seals and the cowling. Repositioning the ignition lead solved both the cooling problem and the chafing problem.

Another common problem is that seals may develop wrinkles or creases when the cowling is installed, preventing them from sealing airtight against the cowling and allowing air to escape. It’s important to look carefully for such problems each time the cowling is removed and replaced, and especially important when new seals have been installed (as was the case with the T210).

Intercylinder Baffles

Inter-cylinder baffles are oddly-shaped pieces of sheet metal that mount beneath and between the cylinders, and force the down-flowing cooling air to wrap around and cool the bottom of the cylinders. (This photo was taken looking up from the bottom of the engine, with the exhaust and induction systems removed to make the baffle easier to see.)

Yet another trouble-prone part of the cooling system is the inter-cylinder baffles. These are small, oddly-shaped pieces of sheet metal mounted below and between the cylinders. Their purpose is to force the down-flowing cooling air to wrap around and cool the bottom of the cylinders, rather than just cooling the top and sides. These baffles are difficult to see unless you know exactly where to look for them, but they are absolutely critical for proper cooling. It’s not at all uncommon for them either to be left out during engine installation or to fall out during engine operation. Either way, the result is major cooling problems.

Awhile back, I noticed that the #3 cylinder of the right engine on my Cessna 310 was running noticeably hotter than its neighbors. I removed the top cowling from the right engine nacelle and carefully inspected all the aluminum baffles and rubber baffle seals, but couldn’t find anything awry. Frustrated, I removed the lower cowlings so that I could inspect the underside of the engine. Sure enough, I discovered that the intercylinder baffle between cylinders #1 and #3 had vibrated loose and shifted about 1/4 inch out of position, creating a significant air leak near the #3 cylinder. Repositioning the baffle properly and tightening its attach bolt to hold it securely in place against the cylinders and crankcase solved the problem.

Why the T210 engine ran hot


Close-up of a fairly significant cooling air leak due to a wrinkle in a flexible baffle seal. This problem was apparent only with the top cowl installed, and could be seen by inspecting through the front intake openings using a flashlight. It’s an excellent idea to look for such baffle seal problems during preflight inspection.

With this as background, I emailed the T210 owner to discourage him from cutting holes in his baffles, and suggested instead that he examine his baffles and seals for existing holes and gaps that could be plugged up to improve cooling. A couple of days later, the owner emailed me back a series of digital photos showing a half-dozen air leaks that he found in his newly installed baffles.

One of those photos revealed a fairly significant cooling air leak due to a wrinkle in a flexible baffle seal. This problem was apparent only with the top cowl installed, and could be seen by inspecting through the front intake openings using a flashlight. Savvy pilots who understand the importance of baffles and seals look for this sort of thing during pre-flight inspection. (Since mechanics do most of their inspecting with the cowlings removed, problems like this sometimes escape their detection.)

I studied the photos and continued my email dialog with the Cessna owner. Between the two of us, we managed to identify a dozen leaks in the T210’s new baffle system. Some were small, others more serious. Combined, they accounted for a significant loss of cooling efficiency. With a few well-placed dabs of high-temp RTV sealant and a little trimming of the flexible seal strips, the owner plugged the leaks in short order, and his engine began running noticeably cooler.

Mike Busch is arguably the best-known A&P/IA in general aviation, honored by the FAA in 2008 as National Aviation Maintenance Technician of the Year. Mike is a 8,000-hour pilot and CFI, an aircraft owner for 50 years, a prolific aviation author, co-founder of AVweb, and presently heads a team of world-class GA maintenance experts at Savvy Aviation. Mike writes a monthly Savvy Maintenance column in AOPA PILOT magazine, and his book Manifesto: A Revolutionary Approach to General Aviation Maintenance is available from in paperback and Kindle versions (112 pages). His second book titled Mike Busch on Engines was released on May 15, 2018, and is available from in paperback and Kindle versions. (508 pages).

Scope That Jug!

continental-cylinder-removalIn 2002, I did something unfortunate: pulled a perfectly good cylinder off of one of the engines of my Cessna 310. If I had it to do over again, I wouldn’t have touched the cylinder. But at the time, I thought I was doing the right thing.

It was the usual story. I had just downed the airplane for its annual inspection, and the first items on my checklist were performing a hot compression check, draining the oil, sending oil samples to the lab, and cutting open the oil filters for inspection.

All the cylinders had compressions in the low- to mid-70s. All but one, that is. That one measured about 60/80 with air leaking past the exhaust valve.

At the time, the engine manufacturer’s guidance on compression tests was Continental Motors service bulletin M84-15, which instructed mechanics that a jug could leak considerably past the rings and still be considered perfectly airworthy. However, any leakage at all past the valves was considered unacceptable, according to TCM, and required the cylinder to come off for repair or replacement.

So off it came.

Pulling a cylinder is a real PITA. I spent two hours removing cooling baffles and the exhaust and induction plumbing. It took me another hour to remove the rocker cover, rocker shafts, rocker arms, pushrods and pushrod housings. Finally, I used a cylinder base wrenches and a big breaker bar to coerce the eight cylinder base nuts loose. About four hours into the project, I held the offending jug in my arms and carried it over to my workbench to survey the damage.

I inspected the cylinder closely, with special attention on the exhaust valve. Surprisingly, I couldn’t see anything wrong. The valve looked normal, as did the rest of the cylinder. Yet it must have been bad, I thought, because it had clearly been leaking air past the exhaust valve.

I sent the cylinder out for re-valving and honing, installed new rings on the piston, then spent another four hours reinstalling them on the engine and replacing the exhaust, intake and baffles.

Like I said, it was a PITA. It cost me more than $500 plus a full day of sweat equity. (Had I not been doing the grunt work myself, the tab would have been at least $1,500.)

Continental pulls a switcheroo

That episode turned out to be a classic case of bad timing. Had my annual inspection come a few months later, that cylinder would never have been yanked. That’s because not long after my jug came off, Continental radically changed its guidance to mechanics regarding cylinder inspection.

On March 28, 2003, the wizards in Mobile issued service bulletin SB03-3 titled “Differential Pressure Test and Borescope Inspection Procedures for Cylinders.”  This 14-page document is arguably the best guidance ever provided to mechanics on the subject of when a cylinder should be pulled. (SB03-3 was recently incorporated into Continental Motors Standard Practice Maintenance Manual X-0, and is no longer a service bulletin.)

Continental’s guidance in SB03-3 differed from its predecessor M84-15 in two crucial respects. First, it reverses Continental’s previous position that even small amounts of leakage past the valves during a compression check is unacceptable and grounds for pulling the cylinder. Many experienced A&Ps considered the “zero leakage past the valves” standard as being unrealistic and after 19 years Continental finally agreed with that assessment.

The other difference is arguably even more important: For the first time, Continental directed mechanics to perform a borescope inspection of the cylinders at each annual inspection, 100-hour inspection, and any other time a compression check is done. Continental’s language about this is quite emphatic: “Continental Motors REQUIRES a cylinder borescope inspection be accomplished in conjunction with the differential pressure test.”

This was huge.

Although SB03-3 officially applies only to Continental engines, the guidance it offers makes good sense for Lycomings, too.

Borescope choices

Lennox Autoscope

Lennox Autoscope

At the time in 2003, borescopes were expensive and exotic devices whose use was pretty much limited to turbine engine inspections. Relatively few piston GA maintenance shops and A&P mechanics owned a borescope, and even fewer had a clue how to use one or what to look for. In SB03-3, Continental specifically recommended a particular make and model of borescope: the “Autoscope” from Lenox Instrument Company in Trevose, Pa. This was a simple, low-cost rigid borescope developed in the mid-1980s for use by auto mechanics, and cost about $1,000. The Lennox Autoscope had excellent optics and provides a remarkably clear view of what’s going on inside a cylinder. However, it was purely optical, and offered no way to take photos or capture digital images.

Since then, borescopes have become much less expensive and feature-rich. For years, I recommended the BK8000 digital borescope (also about $1,000) which provides excellent image quality and the ability to view images on a screen or capture them as JPEG files on a computer.

Vividia Ablescope VA-400

Vividia Ablescope VA-400

Last year, I purchased a Vividia Ablescope VA-400 from Amazon for less than $200. This is an amazingly inexpensive rigid digital borescope with the unique ability to adjust its viewing angle to anything between 0 and 180 degrees. The unit doesn’t come with an imaging device, but it has a USB cable that can be connected to any notebook computer or Android tablet or phone with a micro-USB port. It comes with both PC software and an Android app. This thing is so cheap that it’s now practical for every aircraft owner to have one.

What to look for

Normal valves

Normal valves

Also A&Ps tend to have little or no training in how to use a borescope, it’s certainly not rocket science. Here’s a photo what valves normally look like. The smaller valve on the left is the exhaust valve, while the larger one on the right is the intake valve. The reddish deposits on the exhaust valve and the brownish ones on the intake valve are typical. These deposits should appear reasonably symmetrical, indicating that the valves are rotating in service as they should be.

Burned exhaust valve

Burned exhaust valve

By way of contrast, here’s a photo of a burned exhaust valve. Note the asymmetrical appearance, especially the highlighted region (white arrows) where the deposits are minimal or absent (because that portion of the valve is running too hot). This is the classic visual signature of a burned valve. If the cylinder leaks air past the exhaust valve during the compression check and if the borescope shows this kind of asymmetrical deposit pattern, you can be relatively certain that the valve is burned and that the cylinder has to come off. But if the valve looks normal under the borescope, some leakage during the compression check is not grounds for removing the cylinder. (Now they tell me!)

Cylinder barrels

Cylinder barrels

The borescope is also a great way to check the condition of the cylinder barrel. Ths photo shows two borescope views of the upper cylinder bore—the so-called “ring step area.” The left view is normal; the right one has abnormal wear and scoring—possibly due to a broken compression ring—and probably needs to come off.

Next time you put your airplane in the shop, ask your mechanic what kind of borescope he uses. If your A&P doesn’t have a borescope or doesn’t know how to use one, educate him (and let him know that it’s now required equipment for any mechanic that works on Continental engines)…or find another mechanic.

Pulling a cylinder without first borescoping it is a lot like performing major surgery without first getting a CT or MRI. Don’t let any mechanic do that to your engine.

Mike Busch is arguably the best-known A&P/IA in general aviation, honored by the FAA in 2008 as National Aviation Maintenance Technician of the Year. Mike is a 8,000-hour pilot and CFI, an aircraft owner for 50 years, a prolific aviation author, co-founder of AVweb, and presently heads a team of world-class GA maintenance experts at Savvy Aviation. Mike writes a monthly Savvy Maintenance column in AOPA PILOT magazine, and his book Manifesto: A Revolutionary Approach to General Aviation Maintenance is available from in paperback and Kindle versions (112 pages). His second book titled Mike Busch on Engines was released on May 15, 2018, and is available from in paperback and Kindle versions. (508 pages).

Checking the Dipstick

Checking the dipstick

There’s a lot more to checking the dipstick than just noting the oil level. The appearance of the oil is at least as important as its quantity.

We’ve been doing it since our earliest days as student pilots. Now that we’re aircraft owners, we still do it as part of our standard preflight ritual. But are we doing it right?

It turns out that there’s a lot more to checking the engine’s oil dipstick properly than just making sure that the oil level is above the minimum-for-flight level listed in the POH. If we really pay attention, we can learn a lot about the condition of our oil and of our engine.

How much oil is needed?

The engines on my Cessna 310 have 12-quart sumps—13 quarts if you include the quart in the spin-on oil filter. When I first acquired the airplane, my mechanic would fill the sump to its maximum capacity at each oil change. It didn’t take me long to discover that the engines didn’t like that, and promptly tossed several quarts out the engine breathers.

My POH states that the “minimum for flight” oil level is 9 quarts. So I asked my mechanic to service the sump to 10 quarts (instead of 12), and I’d add a quart of make-up oil when the level got down to 9 quarts. That worked better, but I was still seeing a fair amount of oil on the underside of the engine nacelles and the outer gear doors.

After I became a mechanic myself and learned about such things, I checked the Type Certificate Data Sheet (TCDS) for my Continental TSIO-520-BB engines, and found that an oil level of 6 quarts was sufficient to make good oil pressure in all flight attitudes from 23° nose-up to 17° nose-down. Armed with this information, I decided to experiment with lower oil levels.

What I discovered was that oil consumption (and the oily mess on the airframe) was drastically reduced if I maintained the oil level at around 8 quarts on the dipstick. Since then, I’ve avoided filling the sump to more than 9 quarts, and I normally do not add make-up oil until the dipstick reads about 7½ quarts. (This still gives me a 1½-quart “cushion” above what the engine needs to operate reliably in all flight attitudes.)

You might wonder why Continental put a 12-quart sump on an engine that requires only 6 quarts. The answer is that FAA certification requirements demand that the engine be designed to hold twice as much oil as it actually needs:

FAR §33.39 Lubrication system.

(a) The lubrication system of the engine must be designed and constructed so that it will function properly in all flight attitudes and atmospheric conditions in which the airplane is expected to operate. In wet sump engines, this requirement must be met when only one-half of the maximum lubricant supply is in the engine.

The TCDS for my TSIO-520-BB engines states that maximum acceptable oil consumption is about one quart per hour. If my engines actually used that much oil, then I’d need to fill the sumps nearly to their maximum capacity to ensure that I had enough oil to make a 5-hour flight without risking oil starvation. But since I know from long experience that my engines use more like 0.1 quart per hour, there’s no reason for me to carry anywhere near that much oil.

Every aircraft engine installation has an optimum oil level at which oil consumption is minimized and the engine is happiest. I would encourage you to experiment to determine what oil level works best for your airplane. Your engine will operate properly at 50% of its maximum oil capacity—guaranteed. As long as you keep the oil level a quart or two above the 50% point, your engine will be happy.

The best time to get an accurate dipstick reading is just prior to the first flight of the day. If you check the oil level shortly after the engine has been run for awhile, the dipstick reading will be noticeably lower because a significant quantity of oil remains adhered to various engine components. Another reading taken 24 hours later will often show an oil level that is ½ to 1 quart higher.

Oil consumption?

Having assured yourself that there’s enough oil in the engine, your next task is to make note of how much oil your engine is using. Keeping track of oil consumption—particularly any significant increase in oil consumption rate—is an important tool for monitoring engine condition.

The most common method of measuring oil consumption is to record how many quarts of make-up oil are added between oil changes, and to divide the total by the number of hours in the oil-change interval. (For example, if the oil is changed after 50 hours and 6 quarts of make-up oil were added during that time, the average oil consumption rate is 50/6 or 8.3 hours per quart.)

Oil consumption graph

Oil consumption isn’t linear—it accelerates as the oil deteriorates over time. The rate of consumption during the first 10 hours after an oil change is a good indication of engine condition.

However, this approach obscures the fact that oil consumption is not linear over the oil change interval. If you keep track of when you add each quart of make-up oil, you’ll find that less oil is consumed at first, and progressively more oil is consumed as the oil’s time-in-service increases.

The reason for this accelerating oil consumption is that the viscosity of the oil decreases as the oil deteriorates. Mineral oils lose viscosity due to a phenomenon called “polymer shearing” in which the long organic molecules are actually broken apart by mechanical action of the engine’s moving parts. Multigrade oils also lose viscosity because their viscosity-index improvers oxidize when exposed to high temperatures.

The increased rate of oil consumption provides tangible evidence that your engine oil is getting “long in the tooth” and ought to be changed soon.

What does your oil look like?

Whenever you check the dipstick, it’s also important to make note of the oil’s appearance—particularly its color and clarity. The oil’s appearance offers valuable clues to its condition and that of your engine.

Oil color

Color and transparency are important indicators of engine condition. When oil becomes dark and opaque, it should be changed. If this happens rapidly, it suggests that the engine has too much blow-by past the rings, or that oil temperature is too hot.

Fresh engine oil has a light amber color and is so transparent that it’s sometimes hard to read the dipstick level. As the oil remains in service, it gradually darkens in color and becomes progressively more opaque.

The darkening of engine oil is caused by contamination and oxidation. Contaminants include carbon (soot), lead salts and sulfur from combustion byproducts that get past the compression rings and into the crankcase (“blow-by”), as well as any dust or dirt that gets past the induction air filter. Oxidation of the oil occurs when it is exposed to high localized temperatures at it circulates through the engine, and results in the formation of coke. Various oil additives are also vulnerable to oxidation, particularly the viscosity-index improvers used in multiweight oils.

Dispersant additives are blended in the oil to help keep these so-called “insolubles” in suspension in order to keep the engine clean and minimize sludge deposits. As the quantity of insolubles in suspension increases, the oil darkens and becomes opaque.

It is important to note how quickly this darkening occurs. If your oil remains relatively light-colored and translucent after 25 hours in service, you can be reasonably confident that your cylinders and rings are in fine condition and that your oil can prudently remain in service for 40 or 50 hours. On the other hand, if your oil gets dark and opaque after 10 or 15 hours, you’d be wise to change your oil more often—perhaps at 25 hours—and you may want to investigate the possibility that one or more cylinders are excessively worn.

Such rapid discoloration is often a good indicator that the oil is distressed. In one study, 90% of oil that appeared abnormally dark on the dipstick was subsequently found by laboratory analysis to be non-compliant with required specifications. Oil that is dark and opaque from blow-by past the rings is very likely to be rich in acids and other corrosive compounds that can attack your cam and lifters, and that’s probably the #1 cause of engines failing to make TBO. Any time your oil appears dark or opaque, you would be wise to drain it and replace it with fresh oil and a new oil filter, regardless of the oil’s time-in-service.

Mike Busch is arguably the best-known A&P/IA in general aviation, honored by the FAA in 2008 as National Aviation Maintenance Technician of the Year. Mike is a 8,000-hour pilot and CFI, an aircraft owner for 50 years, a prolific aviation author, co-founder of AVweb, and presently heads a team of world-class GA maintenance experts at Savvy Aviation. Mike writes a monthly Savvy Maintenance column in AOPA PILOT magazine, and his book Manifesto: A Revolutionary Approach to General Aviation Maintenance is available from in paperback and Kindle versions (112 pages). His second book titled Mike Busch on Engines was released on May 15, 2018, and is available from in paperback and Kindle versions. (508 pages).

Temperature, Temperature, Temperature

I’ve had wonderful luck with piston aircraft engines throughout my nearly 50 years as an aircraft owner. All the engines on my airplanes have made TBO with minimal maintenance along the way, and in recent years they’ve gone far, far beyond TBO.

For decades, I was convinced that the secret of my success was the fact that I “babied” my engines, typically limiting my cruise power settings to no more than 60 or 65 percent power. I felt that sacrificing a little airspeed in exchange for long engine life and reduced maintenance cost was a good tradeoff.

I’ve come to learn, however, that such “babying” is one way to achieve long engine life, but it’s not the only way. That’s because it’s not POWER that damages out engines—it’s TEMPERATURE. It turns out you can run these engines as hard as you like so long as you are obsessive about keeping temperatures under control.

Or as my late friend, powerplant guru and former Continental Motors tech rep Bob “Mose” Moseley used to say, “There are three things that affect how long your engine will last: (1) temperature, (2) temperature, and (3) temperature!”

It’s all about the heat

CHTOur piston aircraft engines are heat engines. They have moving parts—notably exhaust valves and valve guides—that are continually exposed to extremely high temperatures in the vicinity of 1,500°F and sometimes hotter. Since engine oil cannot survive temperatures above about 400°F, these moving parts must function with no lubrication. They depend on extremely hard metals operating at extremely close tolerances at extremely high temperatures with no lubrication. Aluminum pistons and cylinder heads are also exposed to these very hot temperatures, despite the fact that aluminum melts at about 1,200°F. It’s nothing short of miraculous, and a testament to outstanding engineering, that these “hot section” components last as long as they do.

The key to making these critical parts last is temperature control, and the most important temperature is cylinder head temperature (CHT). Mose monitored and overhauled these engines for nearly four decades, and he swore to me that an engine that is operated at CHTs above 400°F on a regular basis will show up to five times as much wear metal in oil analysis as an identical engine that is consistently limited to CHTs of 350°F or less. “It’s amazing how much a small increase in CHT can accelerate engine wear,” Mose said.

As critical as CHT is, many owners don’t have a clue whether their CHTs are 400°F+ or 350°F-. That’s because the engine instrumentation provided by most aircraft manufacturers is pathetically inadequate. The typical factory CHT gauge looks at only one cylinder, and it’s not necessarily the hottest one. Further, the typical factory CHT gauge often isn’t even calibrated, and its green arc extends up to a ridiculously hot 460°F (for Continentals) or 500°F (for Lycomings). Those numbers may be okay as emergency red lines, but they’re horribly abusive for continuous operation. If all you have is factory gauges, you could easily be cooking your cylinders to death while blissfully thinking that all is okay because the CHT gauge is well within the green arc.

To know what’s really going on in front of the firewall, you have to have a modern multiprobe engine analyzer with a digital readout. Such instrumentation isn’t cheap—figure $2,500 for a single or $5,000 for a twin, installed—but if it saves you from having to replace a couple of jugs en route to TBO, it has more than paid for itself. Installing a digital engine analyzer is probably the best money you can spend on your airplane.

Fuel system setup

MaintenanceFor takeoff and initial climb, we normally are at wide-open throttle, full-rich mixture, maximum RPM (if we have a constant-speed prop), and wide-open cowl flaps (if we have those). So there’s not much we can do from the cockpit to affect CHT during these phases of flight.

What does affect CHT is how our full-power fuel flows are adjusted. Unfortunately, it is shockingly common to see damagingly high CHTs due to improperly adjusted fuel flows, particularly in fuel-injected engines. It is not unusual for the fuel flows to be set wrong from the day an engine is installed, and never to be checked or adjusted all the way to TBO. The owner winds up going through cylinders every 500 hours and never knowing why (or blaming the manufacturer).

In part, the problem lies with mechanics who don’t fully understand how critical it is to test and adjust the fuel system setup on a regular basis. Continental recommends that the fuel system setup on its fuel-injected engines be checked and adjusted several times a year to account for seasonal changes. I’ll grant that’s a bit anal, but most Continental-powered airplanes go year after year without this ever being done, and many shops that maintain these airplanes don’t even have the necessary test equipment to do it.

Even when mechanics do test and adjust the fuel system, they often adjust it wrong. For example, Continental Manual M-0 (formerly SID97-3G) contains a lengthy table that specifies full-power fuel flow as a range (minimum and maximum). The “fine print” instructs mechanics to adjust the full-power fuel flow to the high end of the specified range, but many mechanics miss this subtlety and adjust it to the middle of the range. Experience shows that this is simply not enough fuel flow to keep CHTs cool during hot-weather takeoffs.

Lycoming engines with RSA fuel injection have no field adjustments for takeoff fuel flow. If it’s inadequate, the fuel servo has to be sent in to a specialty shop for bench checking and adjustment.

Then there’s the problem of aftermarket engine modifications. For example, engines that have been retrofitted with Superior’s Millennium cylinders often run higher CHTs than they did with their original factory cylinders. That’s because Millennium cylinders have substantially better “volumetric efficiency” than factory cylinders—in other words, they breathe better. Since they breathe more air during every combustion cycle, they need more fuel to maintain the same fuel/air mixture. The full-power fuel flow marked on your fuel-flow gauge may simply not be high enough if you have Millennium cylinders installed.

Even worse are turbocharged engines with aftermarket intercoolers installed. The intercooler reduces the temperature of the air that the cylinder breathes, making it denser. Denser air demands more fuel to maintain the desired fuel/air mixture, so full-power fuel flow must be increased significantly above original factory specifications. Too often this is not done, and the result is fried cylinders.

Many A&Ps are reluctant to adjust takeoff fuel flow above red-line. However, if you have Millennium cylinders, an aftermarket intercooler, or some other “mod” that allows your engine to produce more power than it did when it left the factory, that’s exactly what must be done to keep your CHTs cool and avoid premature cylinder failure.

Enough fuel flow?

MP and FF guage comboHow can you tell if your full-power fuel flow is adequate? If you’re limited to factory gauges, you probably can’t, at least with any precision. About the best you can to is to watch your fuel flow gauge (if you have one).

A good rule of thumb is to multiply your engine’s maximum rated horsepower by 0.1 to obtain the minimum required fuel flow in gallons-per-hour, or by 0.6 for pounds-per-hour. For example, if your engine is rated at 285 horsepower, your takeoff fuel flow should be at least 28.5 GPH; if it’s rated 310 horsepower, the minimum should be 31.0 GPH. If your takeoff fuel flow is significantly less than this, have your mechanic crank it up. And don’t forget that if you have Millennium cylinders or an aftermarket intercooler, your engine might be producing a few percent more horsepower than what the book says, so it might need a few percent more fuel flow.

Now if you have a digital multiprobe engine analyzer, it’s easy to tell if your fuel flow is adjusted high enough. Just make sure none of your CHTs exceed 380°F during takeoff and climb for Continentals or 400°F for Lycomings. Lower is even better.

What about cruise?

Cruise flight represents the lion’s share of our flying time. Just as in takeoff and climb, it’s essential to keep all our CHTs at or below 380°F (for Continentals) or 400°F for Lycomings during cruise to achieve good cylinder longevity, and lower is even better. There are basically three different strategies for keeping CHTs low during cruise:

  • Baby the engine
  • Operate very rich
  • Operate lean-of-peak

All three strategies work, and conscientious use of any of them will give you a good shot at making TBO with minimum cylinder problems. But each has its pros and cons. Let’s take a closer look.

Engine graph

The mixture that many POHs refer to as “recommended lean mixture” is 50°F rich of peak EGT. As this graph shows, using that mixture results in very nearly the highest possible CHT. To reduce CHTs to the level required for good cylinder longevity, you need to do one of three things: (1) reduce power, (2) operate very rich, or (3) operate lean-of-peak.

Baby the engine

Many POHs talk about operating at three alternative mixture settings: “best power mixture” (~125°F rich-of-peak), “recommended lean mixture” (~50°F rich of peak, and “best economy mixture” (~peak EGT). It turns out that “recommended lean mixture” (~50°F ROP) is just about the worst possible mixture setting for keeping CHT low.  If you look at Figure 1, you’ll see that CHT reaches a maximum very close to 50°F ROP. So if you want to operate at “recommended lean mixture” and simultaneously keep CHT low, there’s only one way to get there: reduce power dramatically (generally 65% power or less). In other words, baby the engine.

Both “best power mixture” (~125°F ROP) and “best economy mixture” (~peak EGT) result in somewhat lower CHTs than does “recommended lean mixture.” At either of these mixture settings, you can usually operate at 70% power or so and still keep CHTs in the acceptable range.

In any of these cases, you’re trading power and airspeed for reduced temperatures and increased longevity. For most of us, that’s a reasonable tradeoff to make.

Operate very rich

But what if you are unwilling to sacrifice power and airspeed? Is it possible to go fast and still keep CHTs low?

Sure it is. We already talked about one way to do this in our discussion of takeoff and initial climb: pour lots of 100LL on the problem. In other words, operate very rich.

How rich? Figure 1 suggests that to reduce CHTs by 25°F, you need to enrich the mixture to about 160°F ROP. For each additional 10°F of CHT reduction, you need to enrich an additional 50°F ROP. Using such very rich mixtures, you can go fast and still stay cool. (This is how Reno racers usually operate.) But before you decide to go this route, consider the downsides.

The most obvious downside is that this strategy is very fuel-inefficient. Compared to “best economy mixture,” the very-rich strategy consumes about 25% more fuel, and reduces range by a similar amount. Advocates of very rich mixtures will tell you that “fuel is cheaper than engines,” but don’t be so sure. At today’s avgas prices, using 25% more fuel in a 300 horsepower engine can cost more than $40,000 over the engine’s TBO, and that’s enough to change out quite a few cylinders.

A second and less obvious downside is that very rich mixtures result in “dirty” combustion with lots of unburned byproducts in the exhaust gas. Operating this way for long periods of time tends to cause deposit buildup on piston crowns, ring grooves, spark plugs and exhaust valve stems. Do it long enough and you could wind up with stuck rings, stuck valves, worn valve guides, and fouled plugs.

Operate lean-of-peak

The third way to reduce CHTs is to lean even more aggressively than the POH recommends and operate on the lean side of peak EGT. Figure 1 shows that you can reduce CHTs by 25°F by leaning to about 10°F LOP. For each additional 10°F of CHT reduction, you need to lean an additional 15°F LOP. Using these very lean mixtures, you can go fast, stay cool, and obtain outstanding fuel economy, all at the same time.

What’s the downside of the LOP approach? The only major downside is that if your engine has uneven mixture distribution among its cylinders, it will usually run unacceptably rough at LOP mixture settings.

Uneven mixture distribution can usually be corrected in fuel-injected engines by “tuning” the fuel injector nozzles to eliminate the mixture imbalances. GAMIjectors are tuned nozzles that are STC’d for the majority of fuel-injected Continentals and Lycomings. Continental now offers its own version of tuned injectors on some of its premium engines.

If your engine is carbureted, you have no injector nozzles to tweak. Most carbureted Lycomings have pretty decent mixture distribution and can be run at least mildly LOP without running rough. Some carbureted Continentals (notably the O-470 used in the Cessna 182) have miserable mixture distribution, making it difficult to run those engines LOP without uncomfortable roughness.

Stay cool!

Whatever strategy you prefer, the important thing is to keep a close watch on your CHTs and ensure that they remain cool. The best way to do this is to install a multiprobe digital engine monitor and program its CHT alarm to go off at 390°F (Continentals) or 410°F (Lycomings). If the alarm goes off during takeoff or initial climb, you’re going to have to get your mechanic to turn up the full-power fuel flow.  If it goes off during cruise, either enrich (if ROP) or lean (if LOP) to bring the CHT down to acceptable levels.

If you don’t have a multiprobe digital engine monitor, install one. The cost of such instrumentation (including installation) is usually less than the cost of replacing one cylinder. Failure to install such instrumentation is a classic case of “penny wise, pound foolish.”

Mike Busch is arguably the best-known A&P/IA in general aviation, honored by the FAA in 2008 as National Aviation Maintenance Technician of the Year. Mike is a 8,000-hour pilot and CFI, an aircraft owner for 50 years, a prolific aviation author, co-founder of AVweb, and presently heads a team of world-class GA maintenance experts at Savvy Aviation. Mike writes a monthly Savvy Maintenance column in AOPA PILOT magazine, and his book Manifesto: A Revolutionary Approach to General Aviation Maintenance is available from in paperback and Kindle versions (112 pages). His second book titled Mike Busch on Engines was released on May 15, 2018, and is available from in paperback and Kindle versions. (508 pages).

The most dangerous thing in aviation?

AOPAfileToolsThere’s an old joke among aircraft mechanics that “the most dangerous thing in aviation is an aircraft owner with a screwdriver.” (Or a wrench, or a toolbox, or a Swiss army knife…)

For many mechanics, this is no laughing matter. I’ve been advocating owner involvement and participation in maintenance for many years, and I’ve gotten a fair amount of push-back from repair station owners and working A&Ps who think I’m doing aviation a great disservice through this advocacy, and feel strongly that aircraft maintenance should be left strictly to the pros (like them).

It’s not hard to understand where this idea originates. I doubt there exists a working general aviation mechanic anywhere who doesn’t have a few dozen horror stories about owner-performed maintenance nightmares he’s found while working on GA aircraft—automotive hoses used in fuel systems; exhaust leaks patched with fiberglass and epoxy; rat’s-nest wiring full of Home Depot plastic-insulated doorbell wire, Scotch electrical tape, Pep Boys’ automotive crimp connectors and cold solder joints; … well, you get the idea. I’m the first to admit that I, too, have seen stuff like this in airplanes that really made me shudder.

(But then again, I’ve also seen plenty of things done by allegedly professional A&P mechanics that made me shudder. Unfortunately, the fact that someone holds an FAA certificate—whether it be a pilot certificate or a mechanic certificate—is no guarantee that he isn’t a jerk.)

Some of the best-maintained aircraft I’ve ever seen are ones maintained largely by their non-A&P-rated owners. After all, no one is more motivated to do a first-class job of maintenance than the person whose posterior and those of his family are on the line.

Some of the most mechanically magnificent GA aircraft I’ve ever seen are kitplanes entirely built and maintained by their owners. I suspect the average homebuilt is better maintained than the average “professionally maintained” spam can.

Let’s face it: There are plenty of aircraft owners who have the knowledge, skill and desire to work on their own aircraft and do a first-class job. On the other hand, there are also lots of aircraft owners who have little or no mechanical aptitude or inclination. Most readily admit that they are mechanically challenged individuals (a.k.a. “all thumbs”) and happily leave the wrench swinging to the pros at their maintenance shop.

Then there are a small minority of owners who tinker with their aircraft even though they don’t know which end of the screwdriver to hold, and wind up doing things that are illegal and unsafe. These are the folks that A&P jokes and horror stories are made of, but in truth they represent only a tiny minority of owners.

You won’t save money

There are lots of reasons to consider getting involved in swinging wrenches on your own aircraft, but generally saving money isn’t one of them. While the labor rates at maintenance shops aren’t exactly cheap, the fact is that you’d probably take an hour to accomplish what a professional A&P can do in 20 minutes. At least that was my experience when I started swinging wrenches on my airplane more than 15 years ago, and that of several aircraft-owner friends who do their own maintenance. Even though I now have a lot more experience and hold an A&P/IA, I’m still a lot slower than a career mechanic who swings wrenches every day.  As owner-mechanics, we consider ourselves safe, competent and careful … but slow.

Think about it. A working A&P can hang a cylinder on an engine in 20 minutes or so. No big deal—install the base O-ring, pre-oil the barrel, insert the piston into the barrel using a ring compressor, lift the jug into position, slide the wrist pin through the piston and con rod, push the jug over the studs, thread on the hold-down nuts, and then torque them into place.

But when I hang a jug, I spend 20 minutes watching the Continental video just to make sure I remember all the necessary steps (since the last time I hung a jug was three years ago), and another 10 minutes looking up the torque values and torque sequence (stuff any working A&P knows from memory because he changes jugs every week). Then I waste five minutes trying to remember where I put my cylinder base wrenches, and another 15 minutes going next door to borrow a 5.25-inch ring compressor. And so it goes.

In other words, when I swing wrenches on my airplane, my work is careful, meticulous, strictly by-the-book … and pathetically slow. I suspect the same is true of most owner-mechanics who only go through one annual inspection a year instead of dozens.

So unless you value your time at less than one-third of your A&P’s shop rate, you’re money ahead to let him do the work.

So why do it?

Good question.

I owned airplanes for 20 years before I first had any interest in picking up a wrench. I never would have guessed that I’d become involved in aircraft maintenance.

After owning a succession of single-engine airplanes, I bought my Cessna T310R in 1987. Eighteen months later, the A&P who had been doing my maintenance relocated, and the mechanic who took his place was relatively young and inexperienced and made me a little nervous. So when the airplane went into the shop for its annual inspection, I decided to hang around and watch, just for peace of mind.

It wasn’t long before “hang around and watch” turned into “hang around and help.” Lots of mechanics wouldn’t have put up with me, but this one did—in fact, he seemed to appreciate my interest, and was very patient in answering my questions and showing me the ropes of basic aircraft maintenance.

Much to my surprise, I found the hands-on work oddly therapeutic—a sharp contrast to my normal daily routine (“slaving over a hot computer keyboard”). I’ve always enjoyed learning new things (my wife calls me a professional student), and I found myself intrigued by how much there was to learn about aircraft maintenance in general and about my Cessna T310R in particular.

Over the next few years I found myself taking on more and more of the maintenance work myself, under the patient supervision of a succession of A&Ps. Clearly, I was hooked.

As I started doing more and more of my own maintenance, I discovered that my aircraft became mechanically better and better. In my past aircraft ownership experience, my airplanes always seemed to have a few squawks waiting for the next time the plane went into the shop. Now, even though the T310R was by far the most complex airplane I’d ever owned, I discovered that it was virtually squawk-free. When anomalies did arise, I’d find myself fixing them immediately, rather than letting them stack up.

So why consider owner-performed maintenance? In my case, the answer is “satisfaction.” The satisfaction that comes from doing something with your hands; from learning something new and complex; from getting to know a complicated piece of machinery in a way that that cannot be achieved without taking it apart and putting it back together; and from flying a squawk-free airplane that receives the finest maintenance that dedication (not money) can buy.

Getting started

Will aircraft maintenance give you the same kind of satisfaction that it does me? There’s only one way to find out, and that is to try it. Remember, I never thought of myself as a wrench-swinging kind of guy—until I tried it and (surprise!) discovered that I liked it.

Regardless of how you think you feel about aircraft maintenance, I strongly suggest that every aircraft owner go through at least one owner-assisted annual inspection. It’ll cost you a week or two out of your busy schedule (consider it a novel vacation idea), and you’ll learn more about your aircraft’s design, construction and condition than you can possibly imagine. You’ll also learn a lot about yourself. You might discover that you enjoy working on your airplane, maybe even that you’ve got a knack for it. Or perhaps that you hate it and/or have absolutely no aptitude for it.

I also suggest you learn how to do some basic preventive maintenance on your airplane—at least how to change the oil and oil filter, and perhaps to clean, gap and rotate the spark plugs. This involves only a couple of hours of work—even the busiest aircraft owner can do it over a weekend. The real beauty of doing your own oil and filter changes—besides the fact that it saves you the hassle of taking your plane to the shop every 25 to 50 hours—is that it forces you to remove the engine cowlings regularly and get up-close-and-personal with your engine. It’s the sort of inspection that pilots really ought to be doing every preflight, but unfortunately can’t be done on most of today’s tightly-cowled aircraft except at oil-change time. Think of an owner-performed oil change as an “advanced preflight.”

What can you do legally?

The FAA has carved out a broad laundry list of so-called “preventive maintenance” tasks that a pilot-rated owner can perform on his aircraft without requiring supervision or sign-off from an A&P mechanic. The relevant regulation is 14 CFR 43.3(g), which reads:

The holder of a pilot certificate issued under Part 61 may perform preventive maintenance on any aircraft owned or operated by that pilot which is not used under Part 121, 129, or 135.

The definition of “preventive maintenance” appears in Appendix A(d) of 14 CFR Part 43, and most owners are surprised to learn just how much maintenance they’re allowed to do on their own recognizance. As an owner/operator, you’re permitted to:

  • Change engine oil
  • Replace fuel and oil filters
  • Service spark plugs
  • Service hydraulic fluid
  • Service battery
  • Lubricate just about anything
  • Change tires and tubes
  • Grease wheel bearings
  • Service landing gear struts
  • Replace fuel/oil hoses
  • Install safety wiring and cotter pins
  • Replace landing and position lights
  • Repair landing light wiring
  • Replace the battery
  • Remove and replace tray-mounted radios (except DMEs and transponders)
  • Change database cards
  • Paint anything except balanced flight controls
  • Repair upholstery
  • Replace side windows
  • Replace seats
  • Replace safety belts
  • Patch airframe, fabric

…and that’s just what you can do on your own without a mechanic’s supervision.

With the cooperation of your friendly neighborhood A&P, there’s almost no maintenance task you can’t do. Here’s what 14 CFR 43.3(d) has to say about that:

A person working under the supervision of [an A&P] may perform … maintenance, preventive maintenance, and alterations … if the supervisor personally observes the work being done to the extent necessary to ensure that it is being done properly and if the supervisor is readily available, in person, for consultation.

In other words, you can do anything that your A&P will let you do (and agrees to supervise and sign-off). In this context, “supervise” means whatever your A&P says it means—the reg says he has to be available for consultation, but that doesn’t mean he has to watch your every move or breathe down your neck. As you earn the trust of your supervising A&P, he’ll probably let you do more and more of your own work and simply drop by to inspect it once you tell him you’re done.

How do you earn your A&P’s trust? Keep in mind that he doesn’t expect you to be an expert—in fact, coming across like a know-it-all is a good way to scare off your mechanic. What’s most important is to demonstrate to your A&P that you know your limits, and that he can trust you to stop and consult with him any time you’re not absolutely sure of what you’re doing. Exhibit a careful, conscientious and humble approach, and your A&P will probably give you lots of latitude.

So try it. You might just like it.

Mike Busch is arguably the best-known A&P/IA in general aviation, honored by the FAA in 2008 as National Aviation Maintenance Technician of the Year. Mike is a 8,000-hour pilot and CFI, an aircraft owner for 50 years, a prolific aviation author, co-founder of AVweb, and presently heads a team of world-class GA maintenance experts at Savvy Aviation. Mike writes a monthly Savvy Maintenance column in AOPA PILOT magazine, and his book Manifesto: A Revolutionary Approach to General Aviation Maintenance is available from in paperback and Kindle versions (112 pages). His second book titled Mike Busch on Engines was released on May 15, 2018, and is available from in paperback and Kindle versions. (508 pages).

Don’t Shoot Yourself in the Foot

How To Shoot Yourself in the FootOver the years, I’ve spent a lot of time hanging around maintenance shops like the proverbial fly on the wall, watching the comings and goings of airplanes and owners and listening to the mechanics talk. In the process, I’ve noticed that owners often wind up inadvertently sabotaging the maintenance of their aircraft by imposing inappropriate time or money pressures.


FridayOne of the worst things an owner can do is to put his aircraft in the shop on Monday for an annual inspection and tell his mechanic “Bill, I’ve just gotta have the airplane by Friday…big weekend family trip!” A week might be enough time to get the work done if there are no surprises, but maintenance is seldom surprise-free.

In the case of an annual that starts on Monday, it might well be Tuesday afternoon or Wednesday morning before the IA has gotten the aircraft all opened up, inspected everything, and actually knows what repairs need to be done and what parts need to be ordered. Now the mechanic is working with a gun to his head. In a good-faith attempt to please you (and avoid a confrontation when your aircraft isn’t ready when promised), he’s likely to rush the work and defer any maintenance that is less than absolutely safety-critical.

Lather, rinse, repeat a few times, and you wind up with an aircraft that isn’t as well maintained as it should be. Is that really what you want? Not to mention you’ll be launching off on your big trip in an aircraft just out of annual without leaving time for a proper post-maintenance shakedown flight (sans passengers). Not smart.

Whenever you put your plane in the shop for annual inspection or major maintenance, be prepared for the plane to be downed for twice the estimated time. Tell yourself that when it comes to aircraft maintenance, it’s better to do it right than to do it fast. If the airplane is done on time, be pleasantly surprised. If it runs over due to unforeseen contingencies, keep your cool and be happy that your mechanic cares enough to do the job right.

Sticker shock

Fighting over moneyAlso high on the shoot-yourself-in-the-foot list is arguing over the bill after your aircraft comes out of annual or major maintenance. This is a great way to win the battle but lose the war. At next year’s annual inspection, your mechanic will remember last year’s argument, and will do everything in his power to keep it from happening again—by deferring any maintenance that is not absolutely critical in a good-faith attempt to minimize the bill. Those deferred items will inevitably come back to bite you, because in the long run it’s always cheaper to fix problems sooner rather than later.

Let me be clear: I’m not advocating a money-is-no-object approach to maintenance. Anyone who knows me or has read my stuff knows that I’m a world-class skinflint who will do almost anything to avoid spending a nickel more than necessary on maintenance. But arguing over the bill after the job is done is not the way to save money, trust me. All it will accomplish is to sabotage the quality of maintenance you receive.

Get involved!

Dirty handsIf you want to keep control over the cost of maintenance (and I’m definitely in favor of that), the way to do it is to get involved early in the process. Tell the IA to call you as soon as he’s completed the inspection but BEFORE he’s started any repairs or ordered any parts.

When the IA calls, pay him a visit and go over the discrepancy list with him. Ask him to give you a time and cost estimate to repair each item on the list. For items that aren’t safety-critical (yet), make a joint decision whether to fix now or defer. (In my experience, most owners will elect to fix more and defer less than what the mechanic would decide on his own.)

When you’re done going through the discrepancy list with your IA, you’ll have a pretty solid estimate of what the final bill will be, so there shouldn’t be any unwelcome surprises. And your mechanic will know that his final bill had better be pretty close to the estimate he gave you, or he’d better have a darn good explanation for why it isn’t.

There’s no better way for an owner to learn how to work effectively with mechanics than to do an owner-assisted annual. By the time you’re through, you’ll have learned how the process works and have a much better idea of how things look on the other side of the wrench. I think every owner owes it to himself to go through this experience at least once. Even if you never do it again, the knowledge you’ll gain will pay dividends for as long as you own an aircraft.

Mike Busch is arguably the best-known A&P/IA in general aviation, honored by the FAA in 2008 as National Aviation Maintenance Technician of the Year. Mike is a 8,000-hour pilot and CFI, an aircraft owner for 50 years, a prolific aviation author, co-founder of AVweb, and presently heads a team of world-class GA maintenance experts at Savvy Aviation. Mike writes a monthly Savvy Maintenance column in AOPA PILOT magazine, and his book Manifesto: A Revolutionary Approach to General Aviation Maintenance is available from in paperback and Kindle versions (112 pages). His second book titled Mike Busch on Engines was released on May 15, 2018, and is available from in paperback and Kindle versions. (508 pages).

Choosing the Express Lane…using your private aircraft for business

Recently I was set to travel from the Central Coast of California to Oregon’s Columbia River Gorge and on into Kalispell, Mont. for a business meeting and a business consultation.

Ready for business

Ready for business

Had I opted to fly commercially the following scenario seems likely: Looking at commercial flights from San Luis Obispo Airport I would have needed to get to the airport an hour early for security, and then fly to Los Angeles or San Francisco for a connection.  From there, I would probably lay over for an hour or so, and connect into Portland.  Since Hood River is 45 miles east of Portland, I would have to rent a car and drive to the business meeting, which would add another two hours to the process.

Imagine that the initial flight leaves San Luis Obispo at 6:00 a.m.  My day would have started around 4:00 a.m. to get to the airport by 5:00 a.m.  The short, 45 minute flight to Los Angeles or San Francisco would be followed by a layover and change of planes.   Let us say I arrived in Portland at 10:30 a.m. and got to the rental car counter about 11:00.  The one-hour drive to Hood River puts me at my meeting at noonish.

Mt. Shasta

Mt. Shasta

Contrast that scenario, which has not even gotten me to Kalispell, to what I actually did in my private aircraft.  I drove twenty minutes to Santa Maria Airport and pre-flighted the Mooney.   I was in the air by 7:30 a.m. and made the 3.5 hour flight right to Hood River Airport, arriving at 11:00 a.m.  Instead of starting the day at 4:00 in the morning and arriving at noon, I had a wonderful flight up through California and by Mount Shasta.  The route took me over Klamath Falls, Sunriver, Bend, and Redmond, Oregon and then I flew down the Columbia River Gorge to the destination airport.  I was also able to take a full tube of toothpaste, water bottles, and even my hair cutting scissors!

After business was complete in Hood River, I departed the following morning for Kalispell, Mont.  Again I chose to land at Kalispell City Airport [S27] versus the larger international airport.  In under two hours my Mooney and I were in Montana ready for the next business consultation.

Besides saving time, are there other reasons to fly your private aircraft versus commercial travel for business?  You bet there are!  Not only do we avoid long waits, security screening that robs us of even a water bottle, and inflexible scheduling, but also we exercise our privilege to fly and help others to see the value of General Aviation. The view from the Mooney was spectacular and I arrived refreshed and ready for business. I also was able to fly. As pilots we get to live in the world 3-D, a view that most don’t get routinely.

General Aviation and General Aviation airports serve America and our business community.  If your business takes you to smaller communities not served by commercial flights, private air travel might just be the ticket for you.

The End

The End

Jolie Lucas is a Mooney owner, licensed psychotherapist, and instrument rated pilot. Jolie presents aviation seminars around the country including Sun n Fun, EAA Oshkosh and AOPA. Jolie is the Vice President of the California Pilots Association. She is the 2010 AOPA Joseph Crotti Award recipient for GA Advocacy. Email: [email protected] Web: Twitter: Mooney4Me

Is Your Aircraft Okay to Fly?

Who decides whether or not your aircraft is airworthy?

Airworthy steampEarlier this year, I wrote an article titled “Fix It Now…Or Fix It Later” that was published in a major general aviation magazine. The article discussed how to deal with aircraft mechanical problems that arise during trips away from home base. It offered specific advice about how pilots and aircraft owners can decide whether a particular aircraft issue needs to be addressed before further flight or whether it can safely wait until the aircraft gets back home. I considered the advice I offered in this article to be non-controversial and commonsense.

I was surprised when I received an angry 700-word email from a very experienced A&P/IA—I’ll call him “Damian” (not his real name)—condemning my article and accusing me of professional malfeasance in advising owners to act irresponsibly and violate various FARs. Damian’s critique started out like this:

After reading Mike Busch’s commentary “Fix It Now … Or Fix It Later,” I must take exception to most, if not all, the points made in his column. I believe his statements are misleading as to the operation of certified aircraft, to the point of being irresponsible for an A&P to suggest or imply that it’s up to the owner/operator whether or not to fly an aircraft with a known discrepancy. The FARs are quite clear on this matter, and there have been numerous certificate action levied on pilots who have operated aircraft with known discrepancies.

Damian went on to state that the FARs require that any aircraft discrepancy, no matter how minor, must be corrected and the aircraft approved for return to service “by persons authorized under FAR 43.7 (typically the holder of a mechanic certificate).” He went on to explain that the owner/operator may only approve for return to service those preventive maintenance items listed in FAR Part 43 Appendix A. He went on:

It should be noted that the FAA does not take into consideration the inconvenience or cost related to addressing a known discrepancy. Nor is it up to the owner/operator to determine the significance of a discrepancy as the FARs do not confer this discretion privilege to the owner/operator.

Damian’s attack on my article continued at great length, making it quite clear that his believe is that pilots and aircraft owners are mere “appliance operators” in the eyes of the FAA, and that only certificated mechanics are empowered to evaluate the airworthiness of an aircraft and determine whether or not it is legal and safe to fly. He ended his diatribe by saying:

I hope that others in the aviation community such as FAA Airworthiness Safety Inspectorss and aviation legal professionals weigh in on this commentary. I believe all will agree that this commentary is misleading and uninformed to the point of being irresponsible even to publish. At the very least, pilots that follows the advice of Busch’s commentary should enroll in the AOPA Pilot Protection Services plan because they’re likely to need it!

Whew! Strong stuff! If Damian is right, then the FAA had better lock me up and throw away the key. Fortunately for me, I believe he isn’t and (at least so far) they haven’t.

Where Damian Has It Wrong

Damian and I do agree on at least one thing: FAR 91.7 does indeed say quite unequivocally that it is a violation to fly an unairworthy aircraft, and that if the aircraft becomes unairworthy in flight, the PIC is obligated to discontinue the flight. I would never suggest for a moment that any pilot fly a known-unairworthy aircraft, at least without a ferry permit. That’s a no-brainer.

The much more difficult question is: Exactly how does the PIC decide whether or not an aircraft is airworthy or unairworthy, and therefore whether he is or isn’t allowed to fly it? On this question, Damian and I part company. In fact, his view and mine seem to be diametrically opposite.

Damian’s view is that almost any aircraft discrepancy requires the involvement of an A&P mechanic to evaluate and clear the discrepancy and approve the aircraft for return to service. I see absolutely nothing in the FARs to support such a position, particularly when it comes to non-commercial aircraft operated under Part 91.

To begin with, the basic airworthiness rule (FAR 91.7) is crystal clear about who is responsible for determining whether or not the aircraft may be flown. It says:

The pilot in command of a civil aircraft is responsible for determining whether that aircraft is in condition for safe flight.

The regulation places the burden squarely on the shoulders of the PIC. I don’t see anything there about A&Ps or repair stations having to be involved, do you?

Looking a bit deeper into the FARs, I can find only three circumstances under which a mechanic is required to get involved in making any sort of airworthiness determination on a Part 91 aircraft used for non-commercial purposes:

  1. Exactly once a year, FAR 91.409 requires that an annual inspection be performed by an A&P/IA or a Repair Station. But the other 364 days of the year, it’s the PIC who determines whether the aircraft is airworthy.
  2. When an Airworthiness Directive or Airworthiness Limitation becomes due, FAR 91.403 requires that a mechanic must certify that the AD or AL has been complied with (with rare exceptions where the PIC may do so).
  3. When an owner actually hires a mechanic to perform maintenance on an aircraft, in which case the mechanic is required to document his work and sign it off to testify that the work was performed properly. Note, however, that the mechanic’s signature in the logbook entry does NOT signify that the aircraft is airworthy, only that THE WORK PERFORMED by the mechanic was done in an airworthy fashion.

This third point is one that is frequently misunderstood by mechanics and owners alike. When I teach this stuff at IA renewal seminars, the hypothetical example I often use to illustrate this important point involves an owner who takes his aircraft to a mechanic for repair. The mechanic immediately observes that the aircraft has two obvious discrepancies: the right main landing gear tire is flat, and the left wing is missing. The owner asks the mechanic to fix the flat tire. The mechanic does so, makes a logbook entry describing the work he did on the right main landing gear, and signs it. His signature denotes only that the work he did (fixing the flat tire) was done properly. When the owner picks up the aircraft, the mechanic tells the owner, “I couldn’t help but notice that your left wing is missing. If you’ll permit me to offer you a word of friendly advice, I would not attempt to fly the aircraft until that issue is resolved.” But the missing left wing does not prevent the mechanic from signing the logbook entry. In fact, the mechanic is required by regulation to sign the logbook entry, regardless of whether the aircraft is airworthy or not. The mechanic’s signature addresses only the work performed by the mechanic, and nothing else.

The PIC’s Burden

If you’re on a trip and some aircraft discrepancy occurs – assuming the aircraft isn’t in the midst of its annual inspection and there’s no AD involved – it is up to you as PIC to determine whether or not that discrepancy makes the aircraft unairworthy or not. If you decide that it does, then you can’t fly the airplane until the airworthiness issue is rectified (and that might require hiring an A&P). On the other hand, if you decide that the discrepancy doesn’t rise to the level of making the aircraft unairworthy, then you’re free to fly home and deal with the issue later.

Under the FARs, it’s totally the PIC’s call. There’s no regulatory obligation for the PIC to consult a mechanic when making such airworthiness determinations. Having said that, however, it would certainly be a wise thing to do if you feel uncomfortable about making the decision yourself. It’s your call.

The FARs provide considerable help to the PIC in making such airworthiness determinations. FAR 91.213(d) describes a specific algorithm for deciding whether or not it’s okay to fly an airplane with various items of inoperative equipment. FAR 91.207 says that it’s okay to fly an aircraft with an inoperative ELT to a place where it can be repaired or replaced, no ferry permit required. FAR 91.209 says that position lights needn’t be working if you’re flying during daylight hours. And so on.

If your experience is anything like mine, what most of us call “squawks” are common occurrences, but the majority of them don’t rise to the level of being airworthiness items that cause us (in our capacity as PIC) to conclude that a fix is required before further flight. Even if you do encounter a genuine airworthiness problem – say a flat tire or dead battery or bad mag drop – that still doesn’t mean that you necessarily need to get a mechanic involved. The FARs provide (in Part 43 Appendix A) a list of roughly three dozen items that a pilot-rated owner or operator is permitted to perform and sign off on his own recognizance (without getting an A&P involved).

If you have a flat tire, for example, you (as a pilot-rated owner) are permitted to repair or replace it yourself. If you have a dead battery, you can charge it, service it, or even replace it. If you have a bad mag drop, the most common cause is a defective or fouled spark plug, and you’re permitted to remove, clean, gap, and replace spark plugs yourself. You are also allowed to make repairs and patches to fairings, cowlings, fabric (on fabric-covered aircraft), upholstery and interior furnishings. You can replace side windows, seat belts, hoses, fuel lines, landing and position lamps, filters, seats, safety wire, cotter pins, and more. You can even remove and install tray-mounted avionics from your panel.

Now, you might well prefer to hire an A&P to do some of these things rather than do them yourself, especially when on the road, far from your hangar and toolbox. I know I certainly would, and I’m an A&P myself. But Damian’s contention that you are compelled by the FARs to place your aircraft in the hands of an A&P any time any sort of discrepancy arises is simply not supported by the regulations.

Contrary to what Damian and many of his A&P colleagues may believe, the FAR’s place the responsibility for determining the airworthiness of the aircraft squarely on the PIC, except for once a year when an IA is required to make an airworthiness determination after performing an annual inspection

My colleague Mac McClellan pointed out to me that this closely resembles how the FAA determines whether a pilot is “airworthy.” One day every year or two or five, we pilots are required by regulation to go get an examination from an Aviation Medical Examiner who pronounces us medically fit to fly, or not. The remaining 364 or 729 or 1,824 days in between, the FAA expects us to self-certify that we’re medically fit. “Can you imagine,” Mac asked me rhetorically, “if we had to go to see an AME every time we got a sore throat or runny nose?”

Mike Busch is arguably the best-known A&P/IA in general aviation, honored by the FAA in 2008 as National Aviation Maintenance Technician of the Year. Mike is a 8,000-hour pilot and CFI, an aircraft owner for 50 years, a prolific aviation author, co-founder of AVweb, and presently heads a team of world-class GA maintenance experts at Savvy Aviation. Mike writes a monthly Savvy Maintenance column in AOPA PILOT magazine, and his book Manifesto: A Revolutionary Approach to General Aviation Maintenance is available from in paperback and Kindle versions (112 pages). His second book titled Mike Busch on Engines was released on May 15, 2018, and is available from in paperback and Kindle versions. (508 pages).

Owners, pilots, and owner pilots

I’ve been thinking a lot lately about the goal differences between helicopter owners and pilots. This could be because of my annual involvement in cherry drying work which is one of the few kinds of work that probably appeal more to owners than pilots.

What Owners Want

I think I can safely say that all owners–whether they own and fly for pleasure or own primarily as part of their business–want to keep owning the helicopter. That means keeping costs low and revenue–if any–as high as possible without jacking up costs so they can continue to meet the financial obligations of ownership: insurance, debt service, storage, required maintenance, registration, taxes, etc.

Of course, if a helicopter is owned as part of a business, the owner’s main goal is probably to build that bottom line. That means maximizing revenue while minimizing expenses. While every helicopter has some fixed costs that come into play whether it flies or not–insurance, hangaring, annual maintenance–an owner can minimize costs by focusing on work that pays even if the helicopter doesn’t fly. That’s why you can lease a helicopter with a monthly lease fee that’s independent of hours flown and why certain types of agricultural work–cherry drying and frost control come to mind–pay a standby fee that guarantees revenue even if the helicopter is idle.

As an owner, I can assure you that there’s nothing sweeter than having your helicopter bring in hundreds or even thousands of dollars a day while it’s safely parked at a secure airport or, better yet, in a hangar.

If the helicopter does have to fly, the owner wants the highest rate he can get for every flight hour and the lowest operating cost. How he achieves those goals depends on his business model, the equipment he has, the services he offers, and the pilots who do the flying.

What Pilots Want

What pilots want varies depending on where they are in their career.

  • Student pilots want to learn. Their goal is to learn what they need to and practice it enough so they can take and pass checkrides. Because they’re paying full price for every hour they fly, they’re not necessarily interested in flying unless it enables them to practice the maneuvers they need to get right on a check ride.
  • New pilots want to fly. Period. Their primary interest is building the time they need to get their first “real” flying job: normally 1,000 to 1,500 hours PIC. They’ll do any flying that’s available. And even though commercial pilots and CFI may be able to get paid to fly, some will fly for free or even pay to fly if the price is right. Indeed, I’ve had more than a few pilots offer to fly for me for free, which makes me sad.
  • Semi-experienced pilots want to build skills. Pilots who have had a job or two and have built 2,000 hours or more of flight time are (or should be) interested in doing the kind of flying that will build new skills or get practice in the skills they want to focus on for their careers. So although they still want to fly, they’re more picky about the flying they do. They’ll choose a job with a tour company that also does utility work over a job with a tour company that doesn’t, for example, if they’re interested in learning long-line skills.
  • Experienced pilots want flying jobs doing the kind of work they like to do and/or paying the money they want to receive for their services. Pilots with a good amount of experience and specialized sills are often a lot pickier about the jobs they take. For some of these pilots, flying isn’t nearly as important as pay and lifestyle. A utility pilot friend of mine routinely turned down jobs if he didn’t like the schedule, just because he didn’t like being away from home more than 10 days at a time. But dangle a signing bonus in front of him and there was a good chance he’d take it.

Of course, there are exceptions to all of these generalizations. Few people fall neatly into any one category.

But what you may notice is that most of them need to fly to achieve their goals, whether it’s passing check rides, building time, learning skills, or bringing home a good paycheck.

And that’s how they differ from owners.

Owner Pilots

I’m fortunate–or unfortunate, if you look at my helicopter-related bills–to be both an owner and a pilot.  I’ve owned a helicopter nearly as long as I’ve been flying: 15 years.

The owner side of me is all about the revenue. I love agricultural contracts that let me park the helicopter on standby and collect a daily fee for leaving it idle. Every hour it doesn’t fly is another flight hour I can keep it before I have to pay that big overhaul bill. (I own a Robinson R44 Raven II, which requires an overhaul at 12 years or 2200 hours of flight time, whichever comes first.) It’s also an hour I don’t have to worry about a mishap doing the somewhat dangerous agricultural flying work I do.

The pilot side of me wants to fly. I love to fly. I bought a helicopter because I felt addicted to flying and needed to be able to get a fix any time. (The business came later, when it had to.)

Owning a helicopter means having a safe place to keep it when it's not flying.

Owning a helicopter means having a safe place to keep it when it’s not flying.

And because I’m an owner, with ultimate say over how the helicopter is used, and a pilot, with a real desire to fly, I can pretty much fly where and when I want to. But when the fun is over I’m the one who has to pay the bill.

Being an owner pilot gives me a unique perspective, an insight into how owners and pilots think and what drives them.

Working Together to Achieve Goals

In a perfect world, owners would think more about pilots and work with them to help them achieve their goals. That means helping them learn, offering them variety in their flying work, and paying them properly for their experience and skill levels.

At the same time in that perfect world, pilots would think more about owners and work with them to help them achieve their goals. That means flying safely and professionally, following FAA (or other governing body) regulations, pleasing clients, taking good care of the aircraft to avoid unscheduled maintenance and repair issues, and helping to keep costs down.

What do you think? Are you an owner or pilot or both? How do you see yourself working with others? Got any stories to share? Use the comments here to get a discussion going.

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