Mike Busch

Quest for a TBO-Free Engine

May 13th, 2014 by Mike Busch

“It just makes no sense,” Jimmy told me, the frustration evident in his voice. “It’s unfair. How can they do this?”

Jimmy Tubbs, ECi’s legendary VP of Engineering

Jimmy Tubbs, ECi’s legendary VP of Engineering

I was on the phone with my friend Jimmy Tubbs, the legendary Vice President of Engineering for Engine Components Inc. (ECi) in San Antonio, Texas. ECi began its life in the 1940s as a cylinder electroplating firm and grew to dominate that business. Starting in the mid-1970s and accelerating in the late 1990s—largely under Jimmy’s technical stewardship—the company transformed itself into one of the two major manufacturers of new FAA/PMA engine parts for Continental, Lycoming and Pratt & Whitney engines (along with its rival Superior Air Parts).

By the mid-2000s, ECi had FAA approval to manufacture thousands of different PMA-approved engine parts, including virtually every component of four-cylinder Lycoming 320- and 360-series engines (other than the Lycoming data plate). So the company decided to take the next logical step: building complete engines. ECi’s engine program began modestly with the company offering engines in kit form for the Experimental/Amateur-Built (E-AB) market. They opened an engine-build facility where homebuilders could assemble their own ECi “Lycoming-style” engines under expert guidance and supervision. Then in 2013, with more than 1,600 kit-built engines flying, ECi began delivering fully-built engines to the E-AB market under the “Titan Engines” brand name.

Catch 22, FAA-style

ECi’s Titan Exp experimental engine

A Titan engine for experimental airplanes.
What will it take to get the FAA to certify it?

Jimmy is now working on taking ECi’s Titan engine program to the next level by seeking FAA approval for these engines to be used in certificated aircraft. In theory, this ought to be relatively easy (as FAA certification efforts go) because the Titan engines are nearly identical in design to Lycoming 320 and 360 engines, and almost all the ECi-built parts are already PMA approved for use in Lycoming engines. In practice, nothing involving the FAA is as easy as it looks.

“They told me the FAA couldn’t approve an initial TBO for these engines longer than 1,000 hours,” Jimmy said to me with a sigh. He had just returned from a meeting with representatives from the FAA Aircraft Certification Office and the Engine & Propeller Directorate. “I explained that our engines are virtually identical in all critical design respects to Lycoming engines that have a 2,000-hour TBO, and that every critical part in our engines is PMA approved for use in those 2,000-hour engines.”

“But they said they could only approve a 1,000-hour TBO to begin with,” Jimmy continued, “and would consider incrementally increasing the TBO after the engines had proven themselves in the field. Problem is that nobody is going to buy one of our certified engines if it has only a 1,000-hour TBO, so the engines will never get to prove themselves. It makes no sense, Mike. It’s not reasonable. Not logical. Doesn’t seem fair.”

I certainly understood where Jimmy was coming from. But I also understood where the FAA was coming from.

A brief history of TBO

To quote a 1999 memorandum from the FAA Engine & Propeller Directorate:

The initial models of today’s horizontally opposed piston engines were certified in the late 1940s and 1950s. These engines initially entered service with recommended TBOs of 500 to 750 hours. Over the next 50 years, the designs of these engines have remained largely unchanged but the manufacturers have gradually increased their recommended TBOs for existing engine designs to intervals as long as 2,000 hours. FAA acceptance of these TBO increases was based on successful service, engineering design, and test experience. New engine designs, however, are still introduced with relatively short TBOs, in the range of 600 hours to 1,000 hours.

From the FAA’s perspective, ECi’s Titan engines are new engines, despite the fact that they are virtually clones of engines that have been flying for six decades, have a Lycoming-recommended TBO of 2,000 hours, and routinely make it to 4,000 or 5,000 hours between overhauls.

Is it any wonder we’re still flying behind engine technology designed in the ‘40s and ‘50s? If the FAA won’t grant a competitive TBO to a Lycoming clone, imagine the difficulties that would be faced by a company endeavoring to certify a new-technology engine. Catch 22.

Preparing for an engine test cell endurance run.

Incidentally, there’s a common misconception that engine TBOs are based on the results of endurance testing by the manufacturer. They aren’t. The regulations that govern certification of engines (FAR Part 33) require only that a new engine design be endurance tested for 150 hours in order to earn certification. Granted, the 150-hour endurance test is fairly brutal: About two-thirds of the 150 hours involves operating the engine at full takeoff power with CHT and oil temperature at red-line. (See FAR 33.49 for the gory details.) But once the engine survives its 150-hour endurance test, the FAA considers it good to go.

In essence, the only endurance testing for engine TBO occurs in the field. Whether we realize it or not, those of us who fly behind piston aircraft engines have been pressed into service as involuntary beta testers.

What about a TBO-free engine?

“Jimmy, this might be a bit radical” I said, “but where exactly in FAR Part 33 does it state that a certificated engine has to have a recommended TBO?” (I didn’t know the answer, but I was sure Jimmy had Part 33 committed to memory.)

“Actually, it doesn’t,” Jimmy answered. “The only place TBO is addressed at all is in FAR 33.19, where it says that ‘engine design and construction must minimize the development of an unsafe condition of the engine between overhaul periods.’ But nowhere in Part 33 does it say that any specific overhaul interval must be prescribed.”

“So you’re saying that engine TBO is a matter of tradition rather than a requirement of regulation?”

“I suppose so,” Jimmy admitted.

“Well then how about trying to certify your Titan engines without any TBO?” I suggested. “If you could pull that off, you’d change our world, and help drag piston aircraft engine maintenance kicking and screaming into the 21st century.”

An FAA-inspired roadmap

I pointed out to Jimmy that there was already a precedent for this in FAR Part 23, the portion of the FARs that governs the certification of normal, utility, aerobatic and commuter category airplanes. In essence, Part 23 is to non-transport airplanes what Part 33 is to engines. On the subject of airframe longevity, Part 23 prescribes an approach that struck me as being also appropriate for dealing with engine longevity.

Since 1993, Part 23 has required that an applicant for an airplane Type Certificate must provide the FAA with a longevity evaluation of metallic  wing, empennage and pressurized cabin structures. The applicant has the choice of three alternative methods for performing this evaluation. It’s up to the applicant to choose which of these methods to use:

  • “Safe-Life” —The applicant must define a “safe-life” (usually measured in either hours or cycles) after which the structure must be taken out of service. The safe-life is normally established by torture-testing the structure until it starts to fail, then dividing the time-to-failure by a safety factor (“scatter factor”) that is typically in the range of 3 to 5 to calculate the approved safe-life of the structure. For example, the Beech Baron 58TC wing structure has a life limit (safe-life) of 10,000 hours, after which the aircraft is grounded. This means that Beech probably had to torture-test the wing spar for at least 30,000 hours and demonstrate that it didn’t develop cracks.
  • “Fail-Safe” —The applicant must demonstrate that the structure has sufficient redundancy that it can still meet its ultimate strength requirements even after the complete failure of any one principal structural element. For example, a three-spar wing that can meet all certification requirements with any one of the three spars hacksawed in half would be considered fail-safe and would require no life limitation.
  • “Damage Tolerance” —The applicant must define a repetitive inspection program that can be shown with very high confidence to detect structural damage before catastrophic failure can occur. This inspection program must be incorporated into the Airworthiness Limitations section of the airplane’s Maintenance Manual or Instructions for Continued Airworthiness, and thereby becomes part of the aircraft’s certification basis.

If we were to translate these Part 23 (airplane) concepts to the universe of FAR Part 33 (engines):

  • Safe-life would be the direct analog of TBO; i.e., prescribing a fixed interval between overhauls.
  • Fail-safe would probably be impractical, because an engine that included enough redundancy to meet all certification requirements despite the failure of any principal structural element (e.g., a crankcase half, cylinder head or piston) would almost surely be too heavy.
  • Damage tolerance would be the direct analog of overhauling the engine strictly on-condition (based on a prescribed inspection program) with no fixed life limit. (This is precisely what I have been practicing and preaching for decades.)

How would it work?

SavvyAnalysis chart

Engine monitor data would be uploaded regularly to a central repository for analysis.

Jimmy and I have had several follow-on conversations about this, and he’s starting to draft a detailed proposal for an inspection protocol that we hope might be acceptable to the FAA as a basis of certifying the Titan engines on the basis of damage tolerance and eliminate the need for any recommended TBO. This is still very much a work-in-progress, but here are some of the thoughts we have so far:

  • The engine installation would be required to include a digital engine monitor that records EGTs and CHTs for each cylinder plus various other critical engine parameters (e.g., oil pressure and temperature, fuel flow, RPM). The engine monitor data memory would be required to be dumped on a regular basis and uploaded via the Internet to a central repository prescribed by ECi for analysis. The uploaded data would be scanned automatically by software for evidence of abnormalities like high CHTs, low fuel flow, failing exhaust valves, non-firing spark plugs, improper ignition timing, clogged fuel nozzles, detonation and pre-ignition. The data would also be available online for analysis by mechanics and ECi technical specialists.
  • At each oil-change interval, the following would be required: (1) An oil sample would be taken for spectrographic analysis (SOAP) by a designated laboratory, and a copy of the SOAP reports would be transmitted electronically to ECi; and (2) The oil filter would be cut open for inspection, digital photos of the filter media would be taken, when appropriate the filter media would be sent for scanning electron microscope (SEM) evaluation by a designated laboratory, and the media photos and SEM reports would be transmitted electronically to ECi.
  • At each annual or 100-hour inspection, the following would be required: (1) Each cylinder would undergo a borescope inspection of the valves, cylinder bores and piston crowns using a borescope capable of capturing digital images, and the borescope images would be transmitted electronically to ECi; (2) Each cylinder rocker cover would be removed and digital photographs of the visible valve train components would be transmitted electronically to ECi; (3) The spark plugs would be removed for cleaning/gapping/rotation, and digital photographs of the electrode ends of the spark plugs would be taken and transmitted electronically to ECi; and (4) Each cylinder would undergo a hot compression test and the test results be transmitted electronically to ECi.

The details still need to be ironed out, but you get the drift. If such a protocol were implemented for these engines (and blessed by the FAA), ECi would have the ability to keep very close tabs on the mechanical condition and operating parameters of each its engines—something that no piston aircraft engine manufacturer has ever been able to do before—and provide advice to each individual Titan engine owner about when each individual engine is in need of an overhaul, teardown inspection, cylinder replacement, etc.

Jimmy even thinks that if such a protocol could be implemented and approved, ECi might even be in a position to offer a warranty for these engines far beyond what engine manufacturers and overhaul shops have been able to offer in the past. That would be frosting on the cake.

I’ve got my fingers, toes and eyes crossed that the FAA will go along with this idea of an engine certified on the basis of damage tolerance rather than safe-life. It would be a total game-changer, a long overdue nail in the coffin of the whole misguided notion that fixed-interval TBOs for aircraft engines make sense. And if ECi succeeds in getting its Titan engine certified on the basis of condition monitoring rather than fixed TBO, maybe Continental and Lycoming might jump on the overhaul-on-condition bandwagon. Wouldn’t that be something?

Max Trescott

When to switch to VLOC on an ILS or VOR approach?

May 5th, 2014 by Max Trescott

VLOC SAC ILS VORHard to believe, but the ubiquitous workhorse IFR GPS receiver, the Garmin 430, was introduced 17 years ago in 1997. With more than 100,000 Garmin 430s and 530s shipped, it still has the largest installed base of any IFR-capable GPS. Yet despite its longevity, pilots are still asking basic questions about it, such as “When should I Load versus Activate?” or “When do I switch to VLOC on an ILS or VOR approach?”

Lest you think any of these questions are trivial, the former question became a full page in my Max Trescott’s GPS and WAAS Instrument Flying Handbook. As for the latter question, there’s finally an official FAA answer and surprisingly, it’s different depending upon whether you’re flying an ILS or a VOR approach.

For a lot of people flying mostly ILSs into the same few airports, the answer may seem simple. They might respond “Well the CDI just switches automatically to VLOC as I’m about to intercept the final approach course.” That is true some of the time, though only for ILS approaches and only if you’ve turned on the ILS CDI Autocapture in the Garmin 430 or 530’s AUX group.

But the automatic switching on an ILS only occurs if you intercept the final approach course between 2 to 15 miles outside the Final Approach Fix (FAF). That’s not a problem for most ILSs, but for a really long one with a large descent of perhaps 5,000 feet or more (e.g. the ILS 31 at Salinas, Calif. or the ILS 32R at Moffett Field, Calif.) the CDI won’t switch automatically as you join the final approach course. In these cases, you’ll need to manually switch it. Of course, you’ll always need to manually switch it for any non-ILS approach that uses a Nav radio, such as Localizer, VOR, VOR/DME, LDA, SDF, and Localizer back course approaches.

How Late Can You Switch?
But when are you required to switch to the Nav radio for primary guidance? Imagine you’re on a checkride and you forget to switch the CDI from GPS to the Nav radio. How far can you proceed along the approach before you fail the checkride because you didn’t switch the CDI to the Nav radio?

The story I heard years ago—but never confirmed so I don’t know if it’s true—was that Garmin and Cessna gave differing guidance on this point, because they were located in different FSDOs and got different guidance from their local FAA regional offices. One said you had to switch the CDI or HSI to the NAV radio as soon as you turned onto the final approach course. The other said that you didn’t have to make the switch until you reached the FAF. Which is correct? Like most things in life, it depends!

The FAA reference for this is AC 90-108, dated March 3, 2011. For an ILS, localizer, LDA, or localizer back course, Section 8. c. says that an RNAV System (e.g. a GPS) cannot be used for “Lateral navigation on LOC-based courses (including LOC Back-course guidance) without reference to raw LOC data.” This means that as soon as you turn onto a localizer or ILS, you need to display course guidance from the Nav radio. On the Garmin 430/530, that means as soon as you turn onto the localizer, you must push the CDI button so VLOC is displayed.

But oddly for a VOR approach, the answer is different. Section 8. b. says that an RNAV System (e.g. a GPS) cannot be used as a “Substitution for the NAVAID (for example, a VOR or NDB) providing lateral guidance for the final approach segment.” The final approach segment always starts at the FAF, which is marked with a Maltese cross. So on a VOR approach, you can fly all the way to the FAF before you need to switch the CDI or HSI to the Nav radio. Fly past the FAF using just the GPS (as I saw a client do a few days ago) and you’ve busted your checkride, and the regulations if you were to do it for real on an IFR flight plan.

How Early Should You Switch?
Waiting until the last possible time to switch the CDI or HSI to the Nav radio rarely makes sense. My guidance to clients is when the controller first begins issuing vectors—meaning you’re no longer using the GPS for primary guidance—switch the CDI or HSI to the Nav radio (unless of course you’re flying a GPS approach). That gives you time to verify that the course is set correctly before you join the approach course.

I saw a great example of why that’s important while teaching last weekend at a Cirrus Pilot Proficiency Program (CPPP) in Concord, Calif. One of the attendees I flew with didn’t switch the HSI to the Nav radio until the moment he turned onto the final approach course for the LDA RWY 19R at KCCR. At that time, I noticed that the HSI’s course pointer was incorrectly set for 191 degrees rather than the 181 degrees required for the approach, but didn’t say anything because I wanted to see if and when he’d catch the error. Had he made the switch earlier, he would have had more time to review his setup and possibly catch this error.

The needle remained centered, though it was pointed 10 degrees away from our heading. As we crossed the FAF, he asked “Now do I turn ten degrees to follow the pink line to the airport?” I was stunned that he came up with that as a possibility, since localizer signals are always beamed out in a straight line with no turns. Clearly he knew there was a problem in the conflicting information he was seeing, but he never considered the possibility that the course was set incorrectly.

The mantra I teach clients is to review “MORSE, Source, Course” as part of their setup for an instrument approach. There’s no need to check the MORSE code ID or to set the CDI Course when flying a GPS approach, but they’re absolutely essential to check and set anytime you’re using the Nav radio.

Why Does the FAA Allow the Switch to Occur Later for a VOR
So why must you switch to the Nav radio as soon as you turn onto an ILS or localizer, but can wait until the FAF to make the switch when flying a VOR approach? Consider an instrument approach with a VOR at the FAF. You might guess that when on the approach outside the VOR, a GPS signal keeps you closer to the centerline than a VOR signal, but that’s only true when you’re more than 6 NM from the VOR. At that point, the GPS is in Terminal mode and full scale CDI deflection is ±1 NM, which matches the ±10° full-scale deflection for a VOR signal at that distance.

Six miles is probably close to the average length of an intermediate segment, so while I have trouble saying these words [choke], the VOR would actually be more precise for navigating the last six miles to the FAF. Yes, a VOR signal scallops around a lot, but usually not much when you’re that close to a VOR.

The real benefit of GPS accuracy when flying a VOR approach occurs when you’re flying the initial segment, almost all of which would be more than 6 NM from a VOR at the FAF. Not only would GPS keep you closer to the centerline, but more scalloping occurs on a VOR signal at that distance.

It’s a little tougher to do the same analysis on an ILS or localizer approach, since the beamwidth of the localizer varies between about 3 to 6°, depending upon the particular installation. Suffice it to say that any approach with a localizer will have a narrower beamwidth, keeping you closer to the centerline, than a VOR approach when at the same distance from the antenna site. Just remember that localizers are more precise, so the FAA wants you to start using the Nav radio as soon as you turn onto one. But VORs are less precise, so you don’t have to switch to the Nav radio until you reach the FAF.

Postscript
After reading this post, a friend emailed suggesting I’d misinterpreted AC 90-108 and came to the wrong conclusion about needing to switch to localizer data as soon as you turn onto the final approach course. I sought clarification from AFS-470 at FAA HQ and they quickly responded confirming that pilots MUST use raw localizer data for primary guidance along the entire localizer. They raised an additional point that a reader also mentioned  in the Comments section. Both pointed out that a pilot can always monitor RNAV (GPS) data as they fly along a localizer. However they cannot use it for primary navigation. The pilot must have raw LOC data displayed on their primary instrumentation and  must use that LOC/VOR data for primary navigation. My thanks to everyone who contributed to this discussion!

Jolie Lucas

From Cheetos® to Gyros: one man’s attempt to engage high school students in aviation business

May 2nd, 2014 by Jolie Lucas
Bob Velker is the Business Liaison & Community Outreach Manager at Chino Airport, CA [KCNO].  As such is he is really an ambassador for the airport and the business park within its boundaries.  He has developed a program for high school students to spend a day learning about industry and career opportunities at the airport.  During my recent tour, he kept repeating that Chino Airport was really a light industrial park, with runways. After my visit, I could see why.

The local high schools receive the benefit of a full-day program for their upper division students including lunch at famous Flo’s Restaurant. The kids get the day away from campus, education about the career vocations offered by an airport, plus a super cool two-week internship possibility.

The syllabus for the day at the airport lists a sampling of the career vocations offered at Chino Airport [as well as many mid-to large airports around the country]

Crew
    • Commercial pilot/co-pilot
    • Operations
    • Instructions
Where opportunity takes flight

Chino Airport…where opportunity takes flight

Maintenance

  • Airframe
  • Engines
  • Detailer
  • Director of Maintenance
  • Logistics

Refurbishment

  • Exterior Paint and Body work
  • Interior Design, Fabric, woodworking, metal working, installation

Air Traffic Control

Computer & Information Technology

Police and Fire Fighting

Ground [Field] Operations

  • Fuel
  • Taxi
  • Support Vehicles
  • Field Markings
  • Taxi/Runway
  • Baggage Handling
  • Food Service
  • Management

Administration

  • Marketing
  • Business
  • Management
  • Finance
  • Customer Service
  • Dispatch

Non-Profits

  • Museums
  • Restoration
  • Historians

During the morning session the students spend time with AeroTrader which has 50 employees in aircraft restoration, repairs, engine re-building, fabrication and machine shop.  They also tour Threshold an FBO that has 60 employees working in charter operations, aircraft maintenance and aircraft management.  Both of these businesses need a mix of vocational and skilled employees.

After lunch at Flo’s the groups go to SCE, a public utilities company with 40 employees. Then on to Mach One Air Charters [8 employees] , DuBois Aviation [20 employees] and ending with the Planes of Fame Air Museum, a non-profit with 35 employees.  Along the way the kids see the tower and ATC system, learn about Young Eagles, and other businesses on field including avionics repair.

At the end of the day, if a student identifies a strong interest in working for one of the employers highlighted in a session they are given the opportunity to participate in a two-week internship.  All of the businesses at Chino, or any airport for that matter, need workers trained through vocational programs or skilled technical programs. Most high schools now offer various tracks to their students to meet those needs.

I think that Bob Velker has struck gold with this idea.  Not only does it get people to the airport other than pilots, it helps to highlight that our airports offer tremendous economic value and are an economic engine for our communities.  The students might be able to “see” themselves in an aviation career other than that of a pilot. Opportunities like this day-long event open young minds to the career possibilities in aviation. As a parent of a teenager myself, I welcome an opportunity for a child to be able to get their head out of the phone, video game, or chip bag, and into the possibilities of a career in aviation.

Jack Olcott

Imagine Mega Mobility

May 1st, 2014 by Jack Olcott

Imagine the advantages of combining an automobile’s ease of operation with an aircraft’s performance.   The resulting mega expansion in mobility would generate huge business opportunities and improve quality of life.

 History shows that transportation improvements expand economic and social benefits.  As stated by James Rood Doolittle in his 1916 tome, The Romance of the Automobile Industry, “Transportation has been the ladder upon which humanity has climbed, rung by rung, from a condition of primitive savagery to the complex degree of civilization enjoyed by man in the twentieth century.”  A vehicle that combined the user friendliness of the car with the speed and range of a typical GA aircraft would bring a new dimension of travel to the twenty-first century.

Today’s automobiles are so easy to operate that obtaining a driver’s license is more commonplace than graduating from high school.  The public feels sufficiently comfortable with their driving abilities that they are willing to rent a car they have never driven previously and venture into a dark and stormy night, even when they are unfamiliar with the surrounding area.   Technology has created very reliable vehicles, in-car navigation systems that assure even remote locations can be found, and highways that are sound.   The resulting mobility supports commerce and unites people wherever roads exist across our nation.

Imagine an aircraft that owners find as easy to operate as an automobile but can travel twice or three as fast and is not constrained to a system of roads.  Users of such a vehicle would have access to vastly more locations than can be reached with the family car. 

Pipe Dream? Absolutely not!  Just as technology enabled the car’s advance, so will technology enable the “aerial automobile” to be a reality.  The first cars, developed in the early 1800s and powered by steam engines, were so heavy that they were legislated against because they destroyed the existing roads.  Gasoline engines and new tires developed before the end of the nineteenth century overcame that obstacle.

Today, new propulsion systems ranging from electric motors driving ducted fans to fuel-efficient diesels are emerging, as are structural designs employing lightweight composites.  Concepts of vertical take-off and landing are within reach. Most exciting, in my opinion, are the advanced avionics systems that would enable the aircraft to operate easily in its own bubble of airspace specified by a 4D (latitude, longitude, height and time) ATC system. Infrastructure development such as an advanced ATC system will follow just as the automobile of 110 years ago stimulated the construction of hard surface roads.  (When the Wrights first flew, there were about 200 miles of paved roads in the USA.)   Applications of today’s automation systems, such as employed in advanced autopilots and drones, will result in handing qualities and operational ease that would require less skill that driving a car.  Operating such an advance personal transport would be comfortable and very safe.

Cost?  In 1903, the George N. Pierce Company introduced its Arrow line of automobiles.  The 1904 Great Arrow sold for $4,000, which was about four times the average person’s annual wage at the time and reflected the limited number of cars sold (between 1901 and 1903, Pierce sold about 170 units.)   Adjusted for inflation, the Great Arrow’s price tag would exceed $102,000 today.

Due in large part to volume production, today’s technologically sophisticated and highly useful automobiles are priced within the reach of the average US worker.  Consider what cars would cost if they were produced at the rate of Bonanza production—about 35 a year.

I contend that an advanced personal transport would be sufficiently beneficial to attract large numbers of buyers and thus be offered at price close to that of a high-end car.  With the application of existing technology and with enlightened infrastructure development, price would not be a show-stopper.

Imaging what benefits such mobility would provide.

John Petersen

The end of ice?

May 1st, 2014 by John Petersen

I don’t know about you, but for me, the rapid buildup of ice on an airplane in flight (next to an engine failure, I suppose), is one of the most attention-getting events in aviation. Like the upcoming ground seen from behind a very slowly turning (and silent) prop blade, the more the ice builds up, the more the mind congers up an invisible brick wall, rapidly getting closer and closer.

A lot of effort over the years has gone into trying to get rid of ice sticking on airplane parts. Early approaches were mechanical, with pneumatically activated leading edge boots, then came weeping wings, heated surfaces and electrostatic systems—all designed to break the bond between the ice and the structural material.

One of the things I mention in the talks that I give around the country about the future of aviation is the extraordinary science and technology breakthroughs that are piling on top of each other to produce the accelerating, exponential change that will reconfigure all aspects of our lives. Out of the innumerable examples of gobsmacking (as the Brits put it) inventions that contribute to this unprecedented shift are a couple new products that point to the possible elimination of the issue of ice in aviation.

LiquiGlideThe first is LiquiGlide, designed by a MIT PhD candidate (he quit school to run the company), which makes surfaces so slick that liquids don’t stick to them. Check out the video on the right. The company suggests that ice on aircraft wings behave the same way as liquid water and therefore will not stick. The presumption is, as I understand it, that the rain is liquid until it hits the surface and then freezes. LiquiGlide advertises aviation anti-icing as one of their industrial applications so it’s likely that commercial applications will be out in the not too distant future.

You can’t get samples of LiquiGlide to try on your airplane, but there’s NeverWet, another hydrophobic coating that advertises anti-icing characteristics that you can try. The video on the left shows a test of coated and uncoated electrical insulators in a freezing rain situation. NeverWet has teamed up with Rust-Oleum to produce a two-part spray product that can be bought at major home improvement stores.

I mention this because AOPA Pilot’s Dave Hirschman told me back in January that he had sprayed this stuff on one wing of his airplane, drove it into an icing environment and watched with pleasure when the uncoated wing acquired ice and the coated one didn’t. Not a scientific study, but it showed that the basic claims appear to be true. Both companies say that their coatings are very durable and only if it is scratched is the underlying surface vulnerable to ice. Interesting stuff.

If you happen to be in the Phoenix area and would like to hear a very wide-ranging review of new things that will revolutionize flying, I’m giving a keynote presentation in the near future in Phoenix opening the Aviation Insurance Association annual meeting on May 5. If you’re there, come by and say hi.

Amy Laboda

Lindbergh and Embry-Riddle Team up on Electric Flight

April 28th, 2014 by Amy Laboda

That is, Lindbergh and Embry-Riddle Aeronautical University (ERAU) are teaming up to research and develop electric light aircraft if the FAA will come around on its recent proposal to practically exclude electric powered aircraft completely from the general aviation experience (see report from AOPA by clicking here) in the U.S. It’s an odd restriction, given the push for more sustainable and affordable propulsion technologies going on in general aviation around the world.

Need proof? Take a look at the excellent reporting on the recent Aero Friedrichshafen air show, held annually in Friedrichshafen, Germany. If you want to see aircraft teetering on the bleeding edge of alternative energy propulsion, that is the place to go.

Lindbergh flies the E-Spyder

Erik Lindbergh, grandson of Charles and Ann Morrow Lindbergh, tapped into that energy years ago because it dovetailed nicely with the green emphasis of his family’s foundation, the Lindbergh Foundation. Yet, his Powering Imagination initiative takes a new step.

“It is critical to create a sustainable future for aviation,” he said, announcing the new program. “Emissions and noise are issues that are causing increasing restrictions on aviation around the world. Solving these challenges will ensure that future generations can share our dreams of flight.”

ERAU’s Professor Pat Anderson, Director of the Eagle Flight Research Center at Embry-Riddle and his students have been working on green flight for years in their Green Flight Program, so the new alliance is a natural for them. They’ve had experience with both a Swiftfuel powered Piper and an electric and solar powered Stemme.

The students and faculty at the ERAU Daytona Beach, Florida campus plan to swap the piston-engine in a Diamond HK36 motorglider to electric power and test it in noise-sensitive areas to demonstrate the potential benefits of electric or hybrid-electric propulsion for significantly reducing noise. The aircraft, which they expect will fly in mid-2015, will also be used for testing new components of electric engines under real-world flight conditions. This airborne test lab will enable more efficient R&D on electric power systems.

In 2016 Lindbergh plans to follow in the footsteps of his grandparents, Charles and Anne Morrow Lindbergh, by retracing their 1931 adventure across the United States, Canada, Siberia, Japan, and China, covering 8,000 nautical miles in a modern floatplane powered by alternative fuels.

It’s a wonderful plan, but first we need to make sure that electric powered and hybrid powered aircraft can do more than just be flying testbeds in the U.S.!

Jamie Beckett

Coming soon to a television near you…

April 22nd, 2014 by Jamie Beckett

In a land that counts television as the great communicator, is there room for a network devoted to aviation? Maybe, maybe not. The answer is probably largely up to you, the viewer. Or more accurately the combined viewership of that magical box that continues to grow wider, larger, thinner, and higher-resolution, even as the available programming becomes increasingly niche oriented.

Today we have a channel for everything, it seems. We’ve got channels about food. There are channels devoted to travel. We’ve got science fiction channels, game show channels, military channels, cartoon channels, and news channels to beat the band. Oh yes, we’ve got music channels, too. Kids channels, movie channels, religious channels, shopping channels, gay channels, independent programming channels, even C-SPAN, perhaps the most important and most snore inducing channel to ever come down the pike. But you know what we don’t have? We don’t have a dedicated aviation channel.

I’m not talking about the occasional aeronautically themed programming, like what we might catch on Speed, or the History Channel, or the Blowing Stuff Up During WWII channel. I mean a channel that’s all about aviation and aerospace. Can you imagine the potential? Can you imagine the challenges?

Whew, what a workload.

Television may look easy, but it’s not. Putting a program on the air is a Herculean task. Building an entire network designed to host programming that fits a specific niche in the market is even harder. There are people working on just those challenges, though. Good people. Smart, dedicated, highly-experienced people who have big dreams, mind-bogglingly extensive spreadsheets, and sizzle reels that make you scratch your head and say out loud, “Why isn’t this on my cable line-up right now?”

Allow me to introduce you to two very ambitious projects. One is an aviation themed television program in the development stage. The other is a fledgling aerospace network that’s looking for a home.

AirFare America came across my plate last year at SUN ‘n FUN. An enthusiastic woman who is the embodiment of effervescence took the time to settle down long enough to show me a clip, walk me through the concept, and thoroughly whet my appetite for a program about the edible delights we find at airports from one corner of the continent to the next. Better than the food are the people they discover. Andrea Vernot’s vision caught my eye, my imagination, and my heart. Who doesn’t love a $100 hamburger now and then? Especially if it comes with a great story on the side. Andrea and her partner got that same idea, built on it, shot some stellar video, and are now in the process of making things happen.

Check out a sample of what they’re trying to bring to your living room screen at: http://www.airfareamerica.net/

As if bringing a new program to the tube isn’t hard enough, Phillip Hurst, late of the Golf Channel, has banded together with a stellar group of aviation brainiacs, astronauts, aerobatic wizards, and filmmakers to launch a concept called Air & Space Television. Focusing on sport, adventure, and lifestyle, the men and women behind Air & Space Television hope to forge a new connection with the broader population. They’re not looking to simply entice pilots and hard-core enthusiasts to watch television on the drab days when the ceilings are too low to launch off on a fun flight. They’re working on a plan that will reach out and grab the casual observer, the daydreaming teenager, the bored housewife (or househusband), the adventure junkie looking for a new outlet, and the family that wants to experience something new and exciting vicariously through the lens of a photographer and crew who get up-close and personal with scenes that would scare the bejeezus out of a rational ground-pounder.

Catch up with the Air & Space Television plan at: http://www.airandspace.tv/

The challenges are many, as you can imagine. But it’s a good sign that they’re out there, Andrea and Phillip and their peers. As long as visionaries with imaginations and a talent from telling a story are among us, there is an excellent chance that aviation will thrive for another century, and then another after that. This activity of flight used to be introduced to little boys who lay in the grass watching clouds drift by. It’s expanded its reach now, accepted an ever more diversified body of participants, and still calls out for new converts – albeit in new and exciting ways that can reach each of us right there in our homes. If only all the pieces would fall together.

It gives me hope to know they’re out there, working toward the day when their dream comes to fruition. To a day when anyone in American can snap on their television and surf right up to a channel that will show everything from a Mercury capsule launching into space, an episode of Black Sheep Squadron, the latest happenings on the International Space Station, or maybe even a piece on how the restaurant at your favorite airport restaurant prepares their signature dish.

This could be a great way to spend a rainy, cold weekend in the future. If only…if only…I wish them all the success in the world.

Martin Rottler

Equipping the Next Generation of Aviation Professionals: GA’s Role

April 17th, 2014 by Martin Rottler

This future pilot’s start will occur not with the airlines but in General Aviation. Are we preparing them?Source

This past week, my department was honored to play host to a member of the United Airlines’ Pilot Development office who spoke at our annual year-end student celebration. He provided an enlightening and interesting perspective to students, faculty and industry members alike on the continuing need for highly trained industry professionals across all segments of civil aviation. This includes pilots (well documented by all and backed up by numerous airlines both regional and major), mechanics, operations professionals (airline and airport) and engineers (aircraft and component).

In addition to hearing from United, I recently attended the National Training Aircraft Symposium at Embry Riddle Aeronautical University with numerous airline representatives and university educators. The discussion surrounding the very real pilot shortage and issues with training was frank and pertinent to today’s flight training environment. The insights gained from the various airline hiring managers and recruiters were very useful to the universities that were present. The discussion did not touch on a key area that I feel should be addressed in the industry moving forward: the very real role the so-called “mom and pop” flight schools around the country play in the professional pilot pipeline.

Like many of my students at Ohio State and former classmates at the University of North Dakota, I arrived at college with a Private Pilot license earned from a flying club in high school and flight experience. There are some very good benefits to doing this. Depending on the student and the university they choose to attend, I often encourage prospective aviators to do the same thing as it saves time (and money!). The experience I attained flying out of two different “mom-and-pop” flying clubs at Centennial Airport in Denver was invaluable. That said, the transition to the “professional pilot” training and mindset required some significant changes to my study skills and habits. These skills and insights (spurned from airline pilot training) don’t often make it from the airlines to universities and other general aviation flight schools.

Here are a few of those insights for those aspiring professional pilots who are getting their start in the GA world and the flight schools starting them I’ve gleaned in the past several years:

It’s never too early to start networking with industry professionals.

Encourage Private Pilot applicants to reach out to one another and those around them. In an industry built on both what you know and who you know, getting an early start on meeting people will be invaluable to students as they progress in their training. A broad network of pilots and other professionals who can recommend and vouch for students will give them a leg up compared to their peers.

Thoroughly prepare students for practical exams.

Even with a shortage of qualified pilots, regional and major airlines alike are wary of hiring pilots with numerous FAA checkride failures. It might seem hard to fathom, but an aspiring 17 year old professional pilot failing a Private Pilot checkride might have career implications into their 20s and 30s with future checkride failures. Having more than two practical test failures significantly reduces the chances of getting hired by an airline. This includes Private Pilot checkride failures.

Emphasize professional conduct and appearance.

When I completed my Private Pilot checkride, my instructor told me to wear a tie lest I be turned away by the DPE. While the 17 year old me thought it strange, this first exposure to professional appearance in aviation makes sense. Would you fly with a pilot who walked through an airport (GA or airline) today with a disheveled appearance? A student who aspires to be a professional pilot needs to remember the first part of the job: professional. This will include dressing for the part. Professional conduct also includes avoiding issues with drugs, alcohol, and the law. Discussion of the implications of drug or alcohol problems and criminal charges should also be a key part of any student’s primary flight training. A drug charge or having more than one DUI will be red flags for airlines looking to hire pilots.

The ultimate point? The airlines, FAA, universities, local flight schools and other stakeholders need to recognize the important role played by the “mom and pop” flight school in getting tomorrow’s professional pilots adequately prepared for life in the cockpit. These “mom and pop” schools also need to recognize this importance and ensure that they are best preparing and equipping their customers yearning for professional pilot careers. Early intervention and coaching on a primary instructor’s part will help prepare students for the next stages of their flying career.

Ron Rapp

Contracting: A Great Career Option for the Professional Pilot

April 16th, 2014 by Ron Rapp

As much as one may love flying, it can be a tough career choice. Many pilots struggle through the food chain only to end up discouraged, if not downright hating their job. We’re all aware of the reasons: low pay, long days, little respect, too much time away from home, difficult working conditions, commuting, regulatory hassles, bankruptcies, furloughs, and ruinously expensive training.

Quite a list, isn’t it?

Ours is a small community; word gets around, and it begs the question, how many have bypassed a flying career altogether because of it? I once read a survey suggesting that most pilots would not recommend the field to their children. Of course, many vocations are in this rickety boat. Even formerly high-flying professions like physician and attorney have lost their luster. The message: “it ain’t what it used to be”.

On the other hand, life is often what we make of it. From bush flying to firefighting, there are many different gigs out there for those willing to take Frost’s road-less-traveled. For the past three years, for example, I’ve been flying as a “contract pilot” and truly enjoy it.

The Contractor

Ready to Ride

It’s kind of a generic term, since anyone who flies as an independent contractor rather than a traditional, W-2 employee fits the definition, but I’ll focus on Part 91 and 135 corporate/charter flying because that’s what I know best.

Contract pilots function as a kind of overflow labor. Operators might need temporary help in the cockpit for a variety of reasons: a full-timer is sick, on vacation, leaves the company, times out due to regulatory limitations, or is unavailable for some other reason. God forbid, maybe they ran into trouble with a checkride or medical exam. Perhaps a trip requires multiple pilots due to length or logistics.

Some companies find it advantageous to run tight on full-time labor and supplement with contract pilots since there are no annual costs for training or benefits. They only have to pay contractors when they’re actually used, so as the flight schedule ebbs and flows, they can gracefully scale their workforce up or down without the inefficiency of, say, leaving full-time, salaried pilots sitting at home for an extended period.

For the pilot, there are both pros and cons to life as a contractor.

The Pros

  • You’ve got some control over your schedule and can decline trips. I really hate doing that, because a) I don’t want the company to stop calling me, and b) you never know when things will slow down, so it’s smart to sock away some acorns for the winter. But if you’ve got a big vacation planned or your best friend is getting married? You’re ultimately in control.
  • We can work for multiple operators, which can provide a bit of protection if the flying slows down at one company.
  • You aren’t tied to a seniority system. If you’re an experienced captain at company A, you needn’t start over as the lowest-paid right seater at company B.
  • Contractors earn far more per day than full-time employees, and therefore needn’t work as many days to reach a given income level. That means better quality of life, especially if you’re married and/or have kids.
  • Contract pilots are typically paid by the day. I might have a five day trip consisting of a flight to Hawaii followed by three days on the island before flying home. That’s five days “on the clock”. It can be a more lucrative system than one where you are compensated based on flight hours. Operators are essentially purchasing your time.
  • You’ll travel the country, if not the world. Instead of a few major airports, on larger aircraft like the Gulfstream, you’ll see places you’d never dream of. Though I haven’t been there — yet — North Korea and the South Pole have both been on the table. (Random note: Jeppesen does publish charts and procedures for Pyonyang!)
  • I always get an honest sense of gratitude from the operators for whom I fly, because by definition I’m helping them out when they really need a pilot. For example, I recently got a call from a Part 91 Gulfstream operator whose pilot broke his arm in the middle of a trip. I airlined out the same day and flew that evening’s leg to Las Vegas, keeping the aircraft on schedule.

The Cons

You knew there had to be a few, right?

  • Contractors inherit all the hassles of being your own boss. Does anyone work harder? From providing your own benefits (don’t get me started about healthcare) to paying self-employment taxes, it’s not always the carefree work-and-go-home experience of a full-time employee.
  • You pay for your own training. On a jet, the annual recurrent training costs run in the thousands. I currently allot $15,000/year for recurrent training and associated costs (airfare, hotels, food, incidentals) on my airplane. The expenses are deductible, which helps a bit, but I figure my first month’s work each year is spent digging my way back to financial “zero”.
  • You can’t control when the phone rings. That can mean short-notice trips and/or weird hours.
  • It can be hard to plan your life out when you never know what days you’ll be working. I average about 10 days a month away, so my philosophy has been to just plan my social life as usual, and make sure people know I sometimes have to reschedule or cancel.
  • Work can conflict with itself. I’ve had three operators call me for a trip on the same day. I can only be in one place at at time, so I “missed out” on two of them.
  • No guarantee of work. But then, history has shown that there are no guarantees in life or aviation for anyone, are there?
  • It can be tough getting started. As with many careers, the best entrée is knowing someone who can get you in the door. Initial start-up costs of obtaining a type rating can be a major barrier.

Throttles

I like contracting because when a trip is offered I know it’s because the operator wants to use me rather than has to use me. Contracting represents some of the best that flying has to offer: adventure, interesting destinations and passengers, phenomenal aircraft, and decent pay for the work I do.

So why don’t more people jump into contracting? Awareness, for starters. Not everyone knows about this little niche. Also, it can be tough to break in to the business. You don’t have to know someone on the inside, but it certainly helps.

The initial expense is probably the largest impediment. The best compensation is found on the larger aircraft, and that means an expensive type rating funded solely by the contractor. Some pilots speculate on their ability to get work by obtaining the type before they have a job to use it on. Unless you’re well-heeled, that’s a big financial risk, but it works out for some people.

There is a rather circuitous way around the type rating burden: start off as a salaried employee and switch to contracting after a couple of years. That way the operator pays for your training and in exchange you accumulate a significant body of experience on the airplane.

FAA to the Rescue! Not.

I should note that contracting in the Part 135 world is a bit harder than it used to be. In the old days, if you were typed and current on an aircraft, you could fly for any charter company that operated that kind of plane. It wasn’t uncommon for a contract pilot to fly for several operators. A few years ago — for reasons no one has been able to adequately explain — the FAA essentially did away with that capability.

Today, a five-figure recurrent only entitles you to work for the certificate holder under whom you trained. It doesn’t matter if you’re a veteran of ten years and 10,000 hours in a Gulfstream IV; if you went to recurrent on Company A’s OpSpec, as far as the FAA is concerned, when you move to Company B you are completely unqualified to operate a G-IV on any Part 135 flight until you’ve been through another recurrent… at your own expense, of course.

At first, this seemed like a potential deal-breaker for contract pilots, but it can help as much as it hurts. Just as the change make it harder for a contractor to work for multiple operators, it also makes it more challenging for that operator to replace a contract pilot since a successor wouldn’t be legal to fly until they went back for recurrent training.

Walking the Aviation Tightrope

Contracting does have something in common with scheduled airlines: it’s not right for everyone. If you’re the type that wants a fixed schedule or has to know exactly how much your bi-weekly paycheck is going to be, this ain’t the place. In addition to all the attributes of a good corporate or charter pilot, contracting requires the ability to run a business and cope with uneven income. Some months will be fantastic. Others, not so much. Even when business is slow, though, I get something valuable: more time at home with friends and family. Like I said at the top, life is what you make of it.

But the ability to earn a six figure income right off the bat while working a relatively small number of days? For me at least, it’s more than worth it. What I want in my flying carer is sustainability, the capacity to survive on this aviation tightrope, and ironically that’s what contracting provides. I want to fly without hating it, and that means avoiding the soul-crushing schedule and monotony of many professional flying jobs.

Mike Busch

How Do Piston Aircraft Engines Fail?

April 9th, 2014 by Mike Busch

Last month, I tried to make the case that piston aircraft engines should be overhauled strictly on-condition, not at some fixed TBO. If we’re going to do that, we need to understand how these engines fail and how we can protect ourselves against such failures. The RCM way of doing that is called Failure Modes and Effects Analysis (FMEA), and involves examining each critical component of these engines and looking at how they fail, what consequences those failures have, and what practical and cost-efficient maintenance actions we can take to prevent or mitigate those failures. Here’s my quick back-of-the-envelope attempt at doing that…

Crankshaft

CrankshaftsThere’s no more serious failure mode than crankshaft failure. If it fails, the engine quits.

Yet crankshafts are rarely replaced at overhaul. Lycoming did a study that showed their crankshafts often remain in service for more than 14,000 hours (that’s 7+ TBOs) and 50 years. Continental hasn’t published any data on this, but their crankshafts probably have similar longevity.

Crankshafts fail in three ways: (1) infant-mortality failures due to improper materials or manufacture; (2) failures following unreported prop strikes; and (3) failures secondary to oil starvation and/or bearing failure.

Over the past 15 years, we’ve seen a rash of infant-mortality failures of crankshafts. Both Cnntinental and Lycoming have had major recalls of crankshafts that were either forged from bad steel or were damaged during manufacture. These failures invariably occurred within the first 200 hours after the new crankshaft entered service. If the crankshaft survived its first 200 hours, we can be confident that it was manufactured correctly and should perform reliably for numerous TBOs.

Unreported prop strikes seem to be getting rare because owners and mechanics are becoming smarter about the high risk of operating an engine after a prop strike. There’s now an AD mandating a post-prop-strike engine teardown for Lycoming engines, and a strongly worded service bulletin for Continental engines. Insurance will always pay for the teardown and any necessary repairs, so it’s a no-brainer.

That leaves failures due to oil starvation and/or bearing failure. I’ll address that shortly.

Crankcase halvesCrankcase

Crankcases are also rarely replaced at major overhaul. They are typically repaired as necessary, align-bored to restore critical fits and limits, and often provide reliable service for many TBOs. If the case remains in service long enough, it will eventually crack. The good news is that case cracks propagate slowly enough that a detailed visual inspection once a year is sufficient to detect such cracks before they pose a threat to safety. Engine failures caused by case cracks are extremely rare—so rare that I don’t think I ever remember hearing or reading about one.

Lycoming cam and lifterCamshaft and Lifters

The cam/lifter interface endures more pressure and friction than any other moving parts n the engine. The cam lobes and lifter faces must be hard and smooth in order to function and survive. Even tiny corrosion pits (caused by disuse or acid buildup in the oil) can lead to rapid destruction (spalling) of the surfaces and dictate the need for a premature engine teardown. Cam and lifter spalling is the number one reason that engines fail to make TBO, and it’s becoming an epidemic in the owner-flown fleet where aircraft tend to fly irregularly and sit unflown for weeks at a time.

The good news is that cam and lifter problems almost never cause catastrophic engine failures. Even with a badly spalled cam lobe (like the one pictured at right), the engine continues to run and make good power. Typically, a problem like this is discovered at a routine oil change when the oil filter is cut open and found to contain a substantial quantity of ferrous metal, or else a cylinder is removed for some reason and the worn cam lobe can be inspected visually.

If the engine is flown regularly, the cam and lifters can remain in pristine condition for thousands of hours. At overhaul, the cam and lifters are often replaced with new ones, although a reground cam and reground lifters are sometimes used and can be just as reliable.

Gears

The engine has lots of gears: crankshaft and camshaft gears, oil pump gears, accessory drive gears for fuel pump, magnetos, prop governor, and sometimes alternator. These gears are made of case-hardened steel and typically have a very long useful life. They are not usually replaced at overhaul unless obvious damage is found. Engine gears rarely cause catastrophic engine failures.

Oil Pump

Failure of the oil pump is rarely responsible for catastrophic engine failures. If oil pressure is lost, the engine will seize quickly. But the oil pump is dead-simple, consisting of two steel gears inside a close-tolerance aluminum housing, and usually operates trouble free. The pump housing can get scored if a chunk of metal passes through the oil pump—although the oil pickup tube has a suction screen to make sure that doesn’t happen—but even if the pump housing is damaged, the pump normally has ample output to maintain adequate oil pressure in flight, and the problem is mainly noticeable during idle and taxi. If the pump output seems deficient at idle, the oil pump housing can be removed and replaced without tearing down the engine.

spun main bearingBearings

Bearing failure is responsible for a significant number of catastrophic engine failures. Under normal circumstances, bearings have a long useful life. They are always replaced at major overhaul, but it’s not unusual for bearings removed at overhaul to be in pristine condition with little detectable wear.

Bearings fail prematurely for three reasons: (1) they become contaminated with metal from some other failure; (2) they become oil-starved when oil pressure is lost; or (3) main bearings become oil-starved because they shift in their crankcase supports to the point where their oil supply holes become misaligned (as with the “spun bearing” pictured at right).

Contamination failures can generally be prevented by using a full-flow oil filter and inspecting the filter for metal at every oil change. So long as the filter is changed before its filtering capacity is exceeded, metal particles will be caught by the filter and won’t get into the engine’s oil galleries and contaminate the bearings. If a significant quantity of metal is found in the filter, the aircraft should be grounded until the source of the metal is found and corrected.

Oil-starvation failures are fairly rare. Pilots tend to be well-trained to respond to decreasing oil pressure by reducing power and landing at the first opportunity. Bearings will continue to function properly at partial power even with fairly low oil pressure.

Spun bearings are usually infant-mortality failures that occur either shortly after an engine is overhauled (due to an assembly error) or shortly after cylinder replacement (due to lack of preload on the through bolts). Failures occasionally occur after a long period of crankcase fretting, but such fretting is usually detectable through oil filter inspection and oil analysis).They can also occur after extreme unpreheated cold starts, but that is quite rare.

Thrown Connecting RodConnecting Rods

Connecting rod failure is responsible for a significant number of catastrophic engine failures. When a rod fails in flight, it often punches a hole in the crankcase (“thrown rod”) and causes loss of engine oil and subsequent oil starvation. Rod failure have also been known to cause camshaft breakage. The result is invariably a rapid and often total loss of engine power.

Connecting rods usually have a long useful life and are not normally replaced at overhaul. (Rod bearings, like all bearings, are always replaced at overhaul.) Many rod failures are infant-mortality failures caused by improper tightening of the rod cap bolts during engine assembly. Rod failures can also be caused by the failure of the rod bearings, often due to oil starvation. Such failures are usually random failures unrelated to time since overhaul.

Pistons and Rings

Piston and ring failures usually cause only partial power loss, but in rare cases can cause complete power loss. Piston and ring failures are of two types: (1) infant-mortality failures due to improper manufacturer or assembly; and (2) heat-distress failures caused by pre-ignition or destructive detonation events. Heat-distress failures can be caused by contaminated fuel (e.g., 100LL laced with Jet A), or by improper engine operation. They are generally unrelated to hours or years since overhaul. A digital engine monitor can alert the pilot to pre-ignition or destructive detonation events in time for the pilot to take corrective action before heat-distress damage is done.

Head SeparationCylinders

Cylinder failures usually cause only partial power loss, but occasionaly can cause complete power loss. A cylinder consists of a forged steel barrel mated to an aluminum alloy head casting. Cylinder barrels typically wear slowly, and excessive wear is detected at annual inspection by means of compression tests and borescope inspections. Cylinder heads can suffer fatigue failures, and occasionally the head can separate from the barrel. As dramatic as it sounds, a head separation causes only a partial loss of power; a six-cylinder engine with a head-to-barrel separation can still make better than 80% power. Cylinder failures can be infant-mortality failures (due to improper manufacture) or age-related failures (especially if the cylinder head remains in service for more than two or three TBOs). Nowadays, most major overhauls include new cylinders, so age-related cylinder failures have become quite rare.

Broken Exhaust ValveValves and Valve Guides

It is quite common for exhaust valves and valve guides to develop problems well short of TBO. Actual valve failures are becoming much less common nowadays because incipient problems can usually be detected by means of borescope inspections and digital engine monitor surveillance. Even if a valve fails completely, the result is usually only partial power loss and an on-airport emergency landing.

Rocker Arms and Pushrods

Rocker arms and pushrods (which operate the valves) typically have a long useful life and are not normally replaced at overhaul. (Rocker bushings, like all bearings, are always replaced at overhaul.) Rocker arm failure is quite rare. Pushrod failures are caused by stuck valves, and can almost always be avoided through regular borescope inspections. Even when they happen, such failures usually result in only partial power loss.

Failed Mag Distributor GearsMagnetos and Other Ignition Components

Magneto failure is uncomfortably commonplace. Mags are full of plastic components that are less than robust; plastic is used because it’s non-conductive. Fortunately, our aircraft engines are equipped with dual magnetos for redundancy, and the probability of both magnetos failing simultaneously is extremely remote. Mag checks during preflight runup can detect gross ignition system failures, but in-flight mag checks are far better at detecting subtle or incipient failures. Digital engine monitors can reliably detect ignition system malfunctions in real time if the pilot is trained to interpret the data. Magnetos should religiously be disassembled, inspected and serviced every 500 hours; doing so drastically reduces the likelihood of an in-flight magneto failure.

The Bottom Line

The bottom-end components of our piston aircraft engines—crankcase, crankshaft, camshaft, bearings, gears, oil pump, etc.—are very robust. They normally exhibit long useful life that are many multiples of published TBOs. Most of these bottom-end components (with the notable exception of bearings) are routinely reused at major overhaul and not replaced on a routine basis. When these items do fail prematurely, the failures are mostly infant-mortality failures that occur shortly after the engine is built, rebuilt or overhauled, or they are random failures unrelated to hours or years in service. The vast majority of random failures can be detected long before they get bad enough to cause an in-flight engine failure simply by means of routine oil-filter inspection and laboratory oil analysis.

The top-end components—pistons, cylinders, valves, etc.—are considerably less robust. It is not at all unusual for top-end components to fail prior to TBO. However, most of these failures can be prevented by regular borescope inspections and by use of modern digital engine monitors. Even whey they happen, top-end failures usually result in only partial power loss and a successful on-airport landing, and they usually can be resolved without having to remove the engine from the aircraft and sending it to an engine shop. Most top-end failures are infant-mortality or random failures that do not correlate with time since overhaul.

The bottom line is that a detailed FMEA of piston aircraft engines strongly suggests that the traditional practice of fixed-interval engine overhaul or replacement is unwarranted and counterproductive. A conscientiously applied program of condition monitoring that includes regular oil filter inspection, oil analysis, borescope inspections and digital engine monitor data analysis can yield improved reliability and much reduced expense and downtime.