Posts Tagged ‘safety’

Those Lousy Checklists

Friday, May 1st, 2015

Ah, the checklist. If Shakespeare was a pilot, he’d have written an ode to it.

Once confined to the world of aviation, formal checklist discipline is now common in hospitals, assembly lines, product design, maintenance, and just about any other instance where loss of essential time, money, or bodily function can result from improper procedures or forgotten items.

Some pilots can’t imagine flying without one. Like a child wandering the yard without their favorite blanket, they’d quite literally be lost without that laminated piece of paper guiding them through each phase of flight. I’ve seen pilots who seemed to enjoy using the checklist more than the actual flying.

Others have a difficult time understanding why a written list is needed at all, especially in simple or familiar aircraft. “Use a flow or mnemonic and let’s get going!”, they’d say. While I disagree with that attitude, I understand where it comes from: too many badly-designed checklists.

As anyone who’s operated a wide variety of aircraft types (I’ve flown over 60) can tell you, poor checklists are more often the rule than the exception, and the worst of them will leave a long-lasting bad taste in your mouth. They disrupt the flow of a flight much the way an actor with poor timing can disrupt a scene.

One of the great aviation mysteries is why so many lousy checklists continue to exist. They’re not limited to small aircraft, either. The manufacturer-provided checklist for the Gulfstream IV, for example, is comically long. I don’t know who designs these things, but I highly doubt it’s the line pilot who’s going to be using it day in and day out.

The answer to such cosmic riddles is far above my pay grade. What I can say for sure is that it’s vital for aviators to understand both the purpose for a checklist and the proper way to use one.

The purpose should be self-evident: to ensure that nothing important gets missed. Lowering the landing gear, setting the pressurization controller, those sorts of items. The key word is important, and I think that’s where many checklists fall apart because once the document gets too long, human nature dictates that pilots will either skip items inadvertently or leave the entire thing stowed.

Proper checklist usage? Now that’s something a bit more complex. When an aviator is new to an aircraft, the checklist serves as a “do” list. In other words, each item is read and then the action is performed. Even if a cockpit flow exists and is being taught, the list will have to be read and performed one step at a time because the pilot is simply unfamiliar with the location of switches and controls.

As time goes by, the flow and/or checklist is slowly memorized. Eventually the pilot reaches the point where they’re actually faster and more comfortable performing the items from memory. There’s absolutely nothing wrong with that. In fact, it’s a good thing, because it allows the checklist to serve as a CHECK list. Once everything is done, you quickly read through the items on the page to ensure you haven’t forgotten anything.

In my experience, it’s not the neophyte who is at greatest risk for missing something, it’s the grizzled veteran who whips through the flows at lightning speed and then neglects to use the checklist at all. It’s overconfidence. They’re so sure they haven’t forgotten anything of life-altering consequence. And to be honest, they’re usually right — but that’s not the point.

I see this kind of failure quite frequently when flying glass panel aircraft with pilots who are computer-centric Type-A personalities. They’re literally too fast with the flows and need to slow down a bit.

Caution is also warranted when circumstances force a pilot to perform tasks out of their normal order. Often this happens due to interruption from ATC, line personnel, passengers, weather, or even another pilot.

Speaking of weather, here’s a case in point: I was in New Jersey getting a jet ready for departure during a strong rainstorm. We had started up the airplane to taxi to a place on the ramp where it was somewhat protected from the weather so our passengers wouldn’t get quite as soaked when they arrived. That simple action broke up the usual preflight exterior flow and as a result I neglected to remove the three landing gear pins. Thankfully the other pilot caught it during his walk-around, but it shows how easily that sort of thing can happen.

The best checklists, the ones that are truly effective, share some common traits. For one thing, they’re short and sweet. They hit the critical items in a logical order and leave the rest out.

In an aerobatic aircraft, a pre-takeoff check would cover the fuel selector, canopy, fuel mixture, flight controls, etc. In a swept-wing business jet, on the other hand, the critical items are different. Flaps become a vital item, because unlike other aircraft, if those aren’t set right the airplane can use far more runway than you’ve got available. It may not even fly at all.

Checklist design and usage is an under-appreciated skill. As with many things in aviation, when it’s done right it’s a thing of elegance. Art, almost. So next time you’re flying, take a critical look at your checklist and the way you use it. How do you — and it — measure up?

The Weakest Link

Thursday, April 16th, 2015

If one particular component of an aircraft was determined to be the root cause of 90% of all accidents, wouldn’t we have an Airworthiness Directive out on it? Wouldn’t it be replaced completely? Well we do have such a component: the pilot.

We’re at the point where this isn’t just an academic exercise. A pilot-free airliner or business aircraft is well within the realm of today’s technology. NASA has been researching single-pilot airline cockpits; that gets us halfway there. Corporate aircraft ranging from King Airs to Citations have been certified and operated by a single pilot for decades.

On the other hand, after the Germanwings disaster virtually every airline now has a policy ensuring there are never less than two people on the flight deck — the exact opposite. So which way should we be heading?

Your average pilot probably doesn’t think of him or herself as the weakest link. I certainly don’t. But those pesky statistics…

It brings to mind the illusory superiority bias, that statistically improbably belief of being above average. The most famous example concerns drivers:

According to a study published in a Swedish Psychology journal (Acta Psychologica) a whopping 93% of Americans consider themselves above average drivers. The sample consisted of students, and while the study was conducted in multiple countries, it because obvious that Americans saw themselves as even better drivers than their Swedish counterparts. The Swedish came in at a much lower 69%.

In another similar study by McCormick, Walkey and Green (1986) drivers rated them 80% above average.

Despite extensive training on hazardous attitudes and ADM, pilots aren’t immune to this phenomenon. We’re still human. In fact, the successful, driven type of personality our avocation attracts probably make it more common than in the automotive world. If 93% of drivers feel they’re above average, one wonders how high the needle swings on the pilot population. Who among us wants to admit that despite the massive investment of time, effort, and money we are still subpar?

Are we the weakest link?

Are we the weakest link?

That sort of acknowledgement can be pretty hard on a person’s self-image, but aviators should care about this phenomenon because nine out of 10 accidents are attributed to pilot error. In other words, we literally are the weakest link.

I certainly include myself in that statement. If I had a dime for every mistake I’ve made over the years! Sometimes I think I’ve made them all. In fact a friend of mine — a professional pilot who is known as an excellent aviator — once said that in reviewing the NASA-style safety reports made by line pilots at his company, “I find I’ve made every one of those mistakes myself. Every single one.”

To err may be human, but it’s grating to find myself making the same mistake multiple times; doing so runs a little too close to Einstein’s definition of insanity. For example, I’ve flown while suffering from active food poisoning on two occasions. The circumstances were not identical, but you’d think I’d have learned enough from one episode to have avoided the other.

The first case hit me during a picnic at the Santa Ynez Airport. I had two choices: stay in town or fly home. I chose the latter, and while I made it back without incident, it was a lousy decision to takeoff when feeling so bad.

The second incident occurred at an aerobatic contest in Delano, California. These contests take place in areas where it’s hot and windy. Pilots assist with contest operation when they’re not flying, meaning we’re busy and spend most of the day out in the sun. It’s common to end up dehydrated even while drinking plenty of water. I ate something which didn’t agree with me, and by the time I realized how bad the poisoning was, I’d already flown a hard aerobatic sequence.

This is why I’ve come to be a big believer in the IMSAFE checklist. Amy Laboda just wrote about the importance of this checklist a few days ago. If we can ensure the biological component of our flying is in airworthy shape, the odds of a safe flight rise considerably. IMSAFE isn’t even a complete checklist. It doesn’t mention nutrituion, for example — something my wife will tell you I sometimes ignore.

Pilots may be the cause of most accidents, but in my experience they’re also the cause of many “saves”. Quantas 32, Apollo 13, United 232, Air Canada 143, and USAir 1549 are just a few famous examples of human ingenuity keeping what should have been an unrecoverable mechanical failure at bay. I know of several general aviation incidents which turned out well due to the creative efforts of the pilots. These typically don’t make the evening news, and I imagine there are countless more we’ll never hear about, because when a flight lands without incident it doesn’t generate much attention or publicity. Accident statistics do us a disservice in that regard.

This is why I feel removing humans from the cockpit is not the answer. Commercial flying already holds claim as the safest form of transportation. Light general aviation is a different story, but that’s the price we pay for the incredible freedom and diversity offered by Part 91. No, we would be better served by focusing on improved aeronautical decision making, self-assessment, and training. As I’ve found through bitter experience, it’s a constant battle. Just because you’ve made a thousand flights without incident doesn’t mean your next one will be safe. It’s up to each of us to maintain vigilance throughout every single one of our airborne days.

Statistically speaking, we are the weakest link. But we don’t have to be.

When to get some Dual on the couch: mental and emotional health needs of pilots

Monday, April 6th, 2015
Take a breath, take an honest look

Take a breath, take an honest look

Recently I suffered three unexpected losses. I use the word suffered on purpose here. In December I needed to get a flight review. I had scheduled this with three instructors, but due to the holidays, I was unable to get it done. In early January I contacted a local CFI that I know only socially. He knew about the losses in my life. After talking with me a few moments, he gently suggested that I was not well enough emotionally to fly that day. Of course, I burst into tears because he was number four on my list of instructors.

After I got done crying about it, I got to thinking about how, as a professional psychotherapist, I was seemingly unable to see the state of my own mental health. Below is an excerpt of an article I wrote for AOPA Pilot as well as a link for online screening tools for depression, anxiety, bi-polar and PTSD.

Here are some simple ways to put you and your emotional health on the pre-flight checklist as well as some ideas on when to get support if needed.

Mood: Think back over the past week. Rate your mood on a 1 to 5 scale with 1 being the lowest, and 5 being a happy mood. What is your average? Has anyone told you that you look tired, depressed, or nervous? Sometimes our spouse or families are the greatest mirrors for us. We might not see our mood, but to them it is written all over our faces.

Sleep: Have you been sleeping well? The average person in a lab setting will sleep a 6-7 hour stretch and take a 1-2 hour nap in the afternoon. Think back and check whether you have had any difficulties falling or staying asleep. Our deep restorative delta sleep typically happens well into an uninterrupted sleep cycle. Think about performing a go-round on every approach, with sleep we simply cannot get down to delta if the cycle is continually disrupted.

Energy: Has your get up and go, got up and went? Do you find yourself drinking coffee or energy drinks just to get through the day? Some pilots find they have too much energy and are unable to relax into a healthy focus. Between the tortoise and the hare, somewhere in the middle of the two is the most efficient.

Anxiety and Worry: Someone once told me that worry is interest on a debt we don’t yet owe. An interesting study on worry shows that it can be healthy in small doses. Worry is a high brain function, one that can help us sort through possibilities and strategies. Too much worry shuts down the function and we can find ourselves in a lower brain: fight, flight, or freeze. 30 minutes of worry once per week is effective. How many minutes this week have you racked up?

Concentration/Focus: Particularly important in being pilot-in command [PIC] is the ability to concentrate and stay focused. If you are noticing that your mind is wandering or you are distracted by worry, it might be best to keep yourself and the aircraft on the ground.

Sex Drive: This might seem a strange item to have on your personal checklist, but the fact is a person’s sex drive can be indicative of emotional health. A lack of desire can be suggestive of a mood problem.

Appetite: Does your favorite food taste good to you? Are you eating for comfort or to excess? Healthy food is fuel for the brain and the body. Make sure that you do not fly without fuel on board.

Bumper Sticker: Ask yourself this question and pay attention to the answer: If you had to summarize your attitude about life to fit on a bumper sticker, what would yours say? Is your bumper sticker upbeat and optimistic, or doubtful and negative?

Below is a link for the Mental Health America online screening tools. These screening tools are for use with adults only. If your screening indicates a problem, it is best to contact a licensed mental health counselor in your community for follow-up.

http://www.mentalhealthamerica.net/mental-health-screen/patient-health

A few days after my crying spell, I completed my flight review and had a great time doing it. My instructor had not flown in a Mooney for some time, and after the necessary maneuvers, I was able to show him a lot about my airplane.

Me and Dad, Christmas Eve

James and Jolie Lucas

One of my losses was the death of my father who was a primary flight instructor in the Army Air Corp and a Mooney pilot for 30 plus years. The day I was to leave for his memorial I was checking and double-checking the weather. I thought to myself, “I wonder if I am okay to fly?” That was the only question I needed to ask. If you wonder if you are okay, you are not okay. I packed up the car and made the five-hour drive with my son. While an hour and a half in the air is quicker, for me, that day, the drive was safer.

Our mental health is equally important as our physical health. We are all subject to the same rules of stress and loss. I am happy that CFI #3 told me he didn’t think I should be flying. His insight could have saved us from a bad outcome. I believe we all do need to have eyes and ears on our fellow pilots. We are a small community and we all get to do something that we love to do. Let’s all make sure we are up to the task emotionally too. Thanks for listening.

 

Flying Backward

Wednesday, February 11th, 2015

“Aviation in itself is not inherently dangerous. But to an even greater degree than the sea, it is terribly unforgiving of any carelessness, incapacity or neglect.”

Aviation insurance pioneer A. G. Lamplugh uttered that oft-quoted phrase more than eighty years ago, and it’s as valid today as it was back then. Like Newton’s Laws of Physics, it’s one of the basic, unchanging truths about flying: certain things simply must be done properly if we’re to avoid disaster in the air. One of the best examples would be dealing with a low-altitude engine failure.

Last week’s TransAsia ATR-72 accident is a potent reminder of this aphorism. While we don’t know the cause yet and probably won’t know the whole story for a year or more, it got me thinking about how oddly things are done in aviation sometimes. For example, airline pilots move “up” the food chain from turboprops to jets. If safety is the paramount concern, that’s backwards. Shouldn’t the most experienced pilots should be exercising their skills on the most challenging aircraft rather than the least?

While jets certainly have their pitfalls and perils, a low-altitude engine failure is generally more challenging in a turboprop. The dead engine’s propeller creates tremendous drag until it’s properly secured. Many multi-engine turboprops are equipped with mechanisms to automatically feather the offending prop, but if that system doesn’t function properly, has been deferred, or simply doesn’t exist, the pilot is faced with six levers in close proximity, only one of which will do the trick. It’s easy to pull the wrong one.

Worse yet, if the craft has an autofeather system, the pilot would logically expect it to function as advertised. He or she would have to first detect the lack of feathering, then run the identify-verify-feather drill. Unlike training scenarios, there’s a major surprise factor at play as well. In a simulator, is anyone really surprised when the engine quits? Of course not. In the real world, pilots make thousands of flights where a powerplant doesn’t fail. As much as you tell yourself with each takeoff that “this could be the one”, empirical evidence in the form of a pilot’s own experience suggests against it. That makes preparation for a low-altitude emergency a constant battle with oneself. Are we always honest about how we’re doing in that fight? Probably not.

When I flew ex-military U-21A turboprops for a government contractor, we did all our training in the actual aircraft. I’ll never forget how marginal the aircraft’s performance was, even when engine failures were handled properly and expediently. We would fly a single-engine approach into Catalina Airport, where the missed approach procedure takes you toward the center of the island and some fairly high terrain. On one training flight the autofeather system initially worked as advertised, but then started to slowly unfeather.

Turboprop flying also comes with increased risk exposure due to the flight profile. A jet pilot might fly one or two legs a day versus five, six, or seven flown by the guy in the turboprop. With more legs comes an increased statistical opportunity for that engine to quit on takeoff. Turboprops also fly at lower altitudes where they tend to be in weather rather than above it.

The reciprocating twin pilot has it even worse when it comes to performance. Most of them have no guarantee of any climb performance at all on one engine, especially with the gear down, and few are equipped with automatic feathering systems. Yet that’s where we all start out.

Contrast this with engine failure in the modern jet, where the pilot need do nothing but raise the landing gear and keep the nose straight. In my aircraft, at least, we don’t even add power on the remaining engine. Unless the plane is literally on fire, we just climb straight out for a minute or two, gaining altitude and doing… nothing. No checklist to run, and only two levers in the throttle quadrant rather than six.

John Deakin described the contrast between prop and jet quite colorfully when he transitioned into the G-IV:

“If you hear a Gulfstream pilot whine about poor performance when high, hot, and heavy, please understand, he’s whining about less than 1,000 feet per minute on one engine. I sometimes feel like slapping a chokehold on, and dragging one of these guys out to the old C-46, loaded, on a hot day, and make him do an engine failure on takeoff, where he’d be lucky to get 50 feet per minute.”

There are other places where you can see this same phenomenon at work in aviation. Consider the world of flight instruction. The least experienced CFIs typically start off by teaching primary students. Again, that’s backwards. It would seem more logical to start instructors off with checkouts and endorsements for experienced pilots or commercial certificate training. Putting the best, most experienced CFIs with the neophytes might help accelerate their progress and alleviate the high student pilot drop-out rate.

The Law of Primacy — something every CFI candidate learns about — tells us that “the state of being first, often creates a strong, almost unshakable, impression. Things learned first create a strong impression in the mind that is difficult to erase. For the instructor, this means that what is taught must be right the first time.” Primary flight training literally sets the foundation of an aviator’s flying life, to say nothing of the fact that teaching primary students is one of the most difficult jobs a CFI can undertake. So why is this critical task mainly entrusted to the newest, least experienced instructors?

The answer to these questions usually comes down to money. The almighty dollar frequently plays a powerful role in explaining the unexplainable in aviation. While it would be unrealistic to deny the importance of financial concerns in defying gravity, whole sections of the aviation ecosystem run backwards and one can’t help but wonder if perhaps safety suffers because of it.

Who’s the Best Pilot?

Monday, December 22nd, 2014

One of the many iconic scenes (so much so that it recurs several times in the film) from The Right Stuff has astronaut Gordon Cooper asking his wife, “Who’s the best pilot you ever saw?” before answering his own question: “You’re lookin’ at him!” Gordo was telling a joke, of course, but it got me thinking about what constitutes a great pilot in the real world.

Accident statistics show that when light GA pilots try to operate on a firmly fixed schedule — for example, around the holidays — the risk level increases. AOPA recently published an Air Safety Alert to that effect, noting “a cluster of GA accidents occurring in close succession.”

Some of this probably has to do with the fact that the holiday season occurs in the winter for those of us living in the northern hemisphere. While the hot months have their own set of challenges, they tend to consist of things which present equal hazard to all aircraft: thunderstorms, high density altitude, etc. But whereas large multi-engine turbojets are well-equipped for cold weather flying, single-engine recips typically operate with minimal anti- and de-icing equipment, if any.

Anyway, it occurs to me that this kind of flying is exactly what we do in the Part 135 world. We operate on someone else’s timetable, and rarely is that schedule created with weather, circadian rhythm, airport staffing hours, or other such operational concerns in mind. As you might expect, the 135 safety record — while far better than Part 91 — does not reach the rarefied heights of the scheduled airlines. Some people feel it should. There are plenty of folks who feel Part 91 should reach that strata as well.

I tend to disagree.

Part 135 has the flexibility to operate at random times and into a far wider variety of places than scheduled airlines. While we do everything possible to make the flights as safe as humanly possible, flexibility cannot help but exact a price. Flying worldwide charter, I don’t know if my next trip will take me to Liberia or Las Vegas. I have to be prepared to go anywhere.

If that sounds incredible, then light general aviation flying should really blow your mind! The non-commercial Part 91 aviating so many of us do for personal reasons takes that freedom and ramps it up a hundred fold. Not only can you go anywhere you want at any time it suits you, you can do it at night, in IMC, in formation, and fly some aerobatics or sight-see along the way. You can fly a weird experimental airplane that you built in your garage. You can tow banners. Drop things from your airplane, then cut them up as they fall to earth? Yes, that’s fine. Fly high… or low. You can change your destination in mid-flight without asking anyone’s permission.

Heck, you can even take off with no destination whatsoever; those are some of my most cherished flights. When I call the VFR clearance delivery frequency at John Wayne Airport and they ask where I’m headed, nothing says freedom quite like using William Shatner’s response from the first Star Trek film: “Out there. That-a-way!”

Wrapping your mind around having the liberty to do those things while not being able to install a radio in your panel without approval from a certification office somewhere in Oklahoma City could cause a migraine… but let’s leave that for another day.

The point is, with added freedom comes added risk. And responsibility. It’s ironic that we think of airline pilots as having the greatest weight on their shoulders when rules, procedures, and operational specifications dictate almost everything they do. I’m not saying their job is easy. It ain’t. But if you’re not in awe of the authority and self-determination placed on your own shoulders every time you launch, think about this: we could have the safety record of the major airlines. All we’d need are the same rules and requirements for flight that they use. Seems to me that would be an awful lot like asking Santa for a big, dirty lump of coal in your stocking.

If there’s a way to have the freedom to land on five hundred foot long strips on the side of a mountain, tackle water runways, engage in flight training, and — most of all — fly to that family Christmas in an airplane with just one reciprocating engine without significantly higher risk than you’ll find on a typical airliner, I’d be quite surprised. But one thing every pilot has in common is that risk management is a major part of the job.

So as you contemplate that cross-country flight to celebrate the holidays with your loved ones, remember that the best pilot isn’t the one who finds the cheapest fuel, stuffs the most presents into the baggage compartment, or makes the softest landing. It’s the one who best manages the risk inherent in that flight.

Right, Gordo?

Upset Recovery Training vs. Aerobatics

Tuesday, October 28th, 2014

Upset recovery training has been all the rage over the past couple of years. A Google search of that exact phrase returns more than 24,000 results. There’s a professional association dedicated to such training. ICAO even declared aircraft upsets to be the cause of “more fatalities in scheduled commercial operations than any other category of accidents over the last ten years.”

Nevertheless, I get the impression that some folks wonder if it isn’t more of a safety fad than an intrinsic imperative. It’s hard to blame them. You can hardly open a magazine or aviation newsletter these days without seeing slick advertisements for this stuff. When I was at recurrent training a couple of months ago, CAE was offering upset recovery training to corporate jet pilots there in Dallas. “If I wanted to fly aerobatics, I’d fly aerobatics!” one aviator groused.

He didn’t ask my opinion, but if he had, I’d remind him that 99% of pilots spend 99% of their time in straight and level flight — especially when the aircraft in question is a business jet. I’m not exaggerating much when I say that even your typical Skyhawk pilot is a virtual aerobat compared to the kind of flying we do on charter and corporate trips. For one thing, passengers pay the bills and they want the smoothest, most uneventful flight possible.

In addition, these jets fly at very high altitudes – typically in the mid-40s and even as high as 51,000 feet. Bank and pitch attitudes tend to stay within a narrow band. Yaw? There shouldn’t be any. The ball stays centered, period. We aim for a level of smoothness that exceeds even that of the airlines. Passengers and catering may move about the cabin frequently during a flight, but it shouldn’t be because of anything we’re doing up front.

Fly like that for a decade or two, logging thousands and thousands of uneventful, straight-and-level hours and the thought of all-attitude flying can become – to put it mildly – uncomfortable. I’ve even seen former fighter pilots become squeamish at the thought of high bank or pitch angles after twenty years of bizjet flying.

Unfortunately, there are a wide variety of things that can land a pilot in a thoroughly dangerous attitude: wind shear, wake turbulence, autopilot failure, mechanical malfunction (hydraulic hard-overs, asymmetric spoiler or flap deployment, etc.), inattention, and last but not least, plain old pilot error. Look at recent high-profile accidents and you’ll see some surprisingly basic flying blunders from the crew. Air France 447, Colgan 3407, and Asiana 214 are just three such examples. It may not happen often, but when it does it can bite hard.

So yes, I think there is a strong need for more manual flying exposure in general, and upset recovery training in particular. This isn’t specific to jet aircraft, because some light aircraft have surpassed their turbine-powered cousins in the avionics department. I only wish the 1980’s era FMS computer in my Gulfstream was as speedy as a modern G1000 installation.

Defining the Problem

To the best of my knowledge, neither the NTSB or FAA provide a standard definition for “upset”, but much like Supreme Court Justice Potter Stewart, we pretty much know it when we see it. The term has generally come to be defined as a flight path or aircraft attitude deviating significantly from that which was intended by the pilot. Upsets have led to loss of control, aircraft damage or destruction, and more than a few fatalities.

As automation proliferates, pilots receive less hands-on experience and a gradual but significant reduction in stick-and-rudder skill begins to occur. The change is a subtle one, and that’s part of what makes it so hazardous. A recent report by the FAA PARC rulemaking workgroup cites poor stick and rudder skills as the number two risk factor facing pilots today. The simple fact is that windshear, wake turbulence, and automation failures happen.

The purpose of upset recovery training is to give pilots the tools and experience necessary to recognize and prevent impending loss of control situations. As the saying goes, an ounce of prevention is worth a pound of cure, and that’s why teaching recovery strategies from the most common upset scenarios is actually a secondary (though important) goal.

What about simulators? They’ve proven to be an excellent tool in pilot training, but even the most high fidelity Level D sims fall short when it comes to deep stalls and loss of control scenarios. For one thing, stall recovery is typically initiated at the first indication of stall, so the techniques taught in the simulator may not apply to a full aerodynamic stall. Due to the incredibly complex and unpredictable nature of post-stall aerodynamics, simulators aren’t usually programmed to accurately emulate an aircraft in a deeply stalled condition. Thus the need for in-aircraft experience to supplement simulator training.

Upset Recovery vs. Aerobatics

It’s important to note that upset recovery training may involve aerobatic maneuvering, but it does not exist to teach aerobatics. Periodically over the years, discussions on the merits of this training will cause a co-worker to broach the subject of flying an aerobatic maneuver in an airplane which is not designed and built for that purpose. This happened just the other day. Typically they’ll ask me if, as an aerobatic pilot, I would ever consider performing a barrel or aileron roll in the aircraft.

I used to just give them the short answer: “no”. But over time I’ve started explaining why I think it’s such a bad idea, even for those of us who are trained to fly such maneuvers. I won’t touch on the regulations, because I think we are all familiar with those. I’m just talking about practical considerations.

Normal planes tend to have non-symmetrical airfoils which were not designed to fly aerobatics. They feature slower roll rates, lower structural integrity under high G loads, and considerably less control authority. You might have noticed that the control surfaces on aerobatic airplanes are pretty large — they are designed that way because they’re needed to get safely into and out of aerobatic maneuvers.

That’s not to say an airplane with small control surfaces like a business jet or light GA single cannot perform aerobatics without disaster striking. Clay Lacy flies an airshow sequence in his Learjet. Duane Cole flew a Bonanza. Bob Hoover used a Shrike Commander. Sean Tucker flew an acro sequence in a Columbia (now known as the Cessna TTx). However, the margins are lower, the aerobatics are far more difficult, and pilots not experienced and prepared enough for those things are much more likely to end up hurt or dead.

Sean Tucker will tell you that the Columbia may not recover from spins of more than one or two turns. Duane Cole said the Bonanza (in which he did inverted ribbon cuts) had barely enough elevator authority for the maneuver, and it required incredible strength to hold the nose up far enough for inverted level flight. Bob Hoover tailored his performance to maneuvers the Shrike could do — he’ll tell you he avoided some aerobatic maneuvers because of the airplane’s limitations.

Knowing those limitations and how to deal with them — that’s where being an experienced professional aerobatic pilot makes the difference. And I’m sure none of those guys took flying those GA airplanes upside down lightly. A lot of planning, consideration, training and practice went into their performances.

Now, consider the aircraft condition. Any negative Gs and stuff will be flying around the cabin. Dirt from the carpet. Manuals. Items from the cargo area. Floor mats. Passengers. EFBs. Drinks. Anything in the armrest or sidewall pockets. That could be a little distracting. Items could get lodged behind the rudder pedals, hit you in the head, or worse.

If the belts aren’t tight enough, your posterior will quickly separate from the seat it’s normally attached to. And I assure you, your belts are not tight enough. Getting them that way involves cinching the lap belt down until it literally hurts. How many people fly a standard or transport category aircraft that way?

Now consider that the engine is not set up for fuel and oil flow under negative Gs. Even in airplanes specifically designed for acro, the G loads move the entire engine on the engine mount. In the Decathlon you can always see the spinner move up an inch or two when pushing a few negative Gs. Who knows what that would do with the tighter clearances between the fan and engine cowl on an airplane like the Gulfstream?

Next, let’s consider trim. The jet flies around with an electric trim system which doesn’t move all that quickly. The aircraft are typically trimmed for upright flight. That trim setting works heavily against you when inverted, and might easily reach the point where even full control deflection wouldn’t be sufficient.

I could go on, but suffice it to say that the more I learn about aerobatics, the less I would want to do them in a non-aerobatic aircraft – and certainly not a swept wing jet! Sure, if performed perfectly, you might be just fine. But any unusual attitude is going to be far more difficult — if not outright impossible — to recover from.

Dang it, Tex!

Every time someone references Tex Johnson’s famous barrel roll in the Boeing 707 prototype, I can’t help but wish he hadn’t done that. Yes, it helped sell an airplane the company had staked it’s entire future on, but aerobatic instructors have been paying the price ever since.

Aerobatic and upset recovery training: good. Experimenting with normal category airplanes: bad. Very bad.

Carbon Monoxide, Silent Killer

Monday, October 20th, 2014

Danger, Carbon Monoxide
On January 17, 1997, a Piper Dakota departed Farmingdale, New York, on a planned two-hour VFR flight to Saranac Lake, New York. The pilot was experienced and instrument-rated; his 71-year-old mother, a low-time private pilot, occupied the right seat. Just over a half-hour into the flight, Boston Center got an emergency radio call from the mother, saying that the pilot (her son) had passed out.

The controller attempted a flight assist, and an Air National Guard helicopter joined up with the aircraft and participated in the talk-down attempt. Ultimately, however, the pilot’s mother also passed out.

The aircraft climbed into the clouds, apparently on autopilot, and continued to be tracked by ATC. About two hours into the flight, the airplane descended rapidly out of the clouds and crashed into the woods near Lake Winnipesaukee, New Hampshire. Both occupants died.

Toxicological tests revealed that the pilot’s blood had a CO saturation of 43% — sufficient to produce convulsions and coma—and his mother’s was 69%.

On December 6 that same year, a physician was piloting his Piper Comanche 400 from his hometown of Hoisington, Kansas, to Topeka when he fell asleep at the controls. The airplane continued on course under autopilot control for 250 miles until it ran a tank dry and (still on autopilot) glided miraculously to a soft wings-level crash-landingin a hay field near Cairo, Missouri.

The pilot was only slightly injured, and walked to a nearby farmhouse for help. Toxicology tests on a blood sample taken from the lucky doc hours later revealed CO saturation of 27%. It was almost certainly higher at the time of the crash.

Just a few days later, a new 1997 Cessna 182S was being ferried from the Cessna factory in Independence, Kansas, to a buyer in Germany when the ferry pilot felt ill and suspected carbon monoxide poisoning. She landed successfully and examination of the muffler revealed that it had been manufactured with defective welds. Subsequent pressure tests by Cessna of new Cessna 172 and 182 mufflers in inventory revealed that 20% of them had leaky welds. The FAA issued an emergency Airworthiness Directive (AD 98-02-05) requiring muffler replacement on some 300 new Cessna 172s and182s.

About 18 months later, the FAA issued AD 99-11-07 against brand new air-conditioned Mooney M20R Ovations when dangerous levels of CO were found in their cabins.

Sidebar: CO Primer

Click on image above for high-resolution printable version.

Not just in winter

A search of the NTSB accident database suggests that CO-related accidents and incidents occur far more frequently than most pilots believe. Counterintuitively, these aren’t confined to winter-time flying with the cabin heat on. Look at the months during which the following accidents and incidents occurred during the 15-year period from 1983 to 1997:

March 1983. The Piper PA-22-150 N1841P departed Tucumcari, N.M. After leveling at 9,600, the right front seat passenger became nauseous, vomited, and fell asleep. The pilot began feeling sleepy and passed out. A 15-year-old passenger in the back seat took control of the aircraft by reaching between the seats, but the aircraft hit a fence during the emergency landing. None of the four occupants were injured. Multiple exhaust cracks and leaks were found in the muffler. The NTSB determined the probable cause of the accident to be incapacitation of the PIC from carbon monoxide poisoning. [FTW83LA156]

February 1984. The pilot of Beech Musketeer N6141N with four aboard reported that he was unsure of his position. ATC identified the aircraft and issued radar vectors toward Ocean Isle, N.C. Subsequently, a female passenger radioed that the pilot was unconscious. The aircraft crashed in a steep nose-down attitude, killing all occupants. Toxicological tests of the four victims revealed caboxyhemoglobin levels of 24%, 22%, 35% and 44%. [ATL84FA090]

November 1988. The Cessna 185 N20752 bounced several times while landing at Deadhorse, Alaska. The pilot collapsed shortly after getting out of the airplane. Blood samples taken from the pilot three hours after landing contained 22.1% carboxyhemoglobin. The left engine muffler overboard tube was broken loose from the muffler where the two are welded. The NTSB determined probable cause to be physical impairment of the pilot-in-command due to carbon monoxide poisoning. [ANC89IA019]

July 1990. While on a local flight, the homebuilt Olsen Pursuit N23GG crashed about three-tenths of a mile short of Runway 4 at Fowler, Colo. No one witnessed the crash, but post-crash investigation indicated that there was no apparent forward movement of the aircraft after its initial impact. The aircraft burned, and both occupants died. Toxicology tests of the pilot and passenger were positive for carboxyhemoglobin. [DEN90DTE04]

August 1990. About fifteen minutes into the local night flight in Cessna 150 N741MF, the aircraft crashed into Lake Michigan about one mile from the shoreline near Holland, Mich. Autopsies were negative for drowning, but toxicological tests were positive for carboxyhemoglobin, with the pilot’s blood testing at 21%. [CHI90DEM08]

July 1991. The student pilot and a passenger (!) were on a pleasure flight in Champion 7AC N3006E owned by the pilot. The aircraft was seen to turn into a valley in an area of mountainous terrain, where it subsequently collided with the ground near Burns, Ore., killing both occupants. A toxicology exam of the pilot’s blood showed a saturation of 20% carboxyhemoglobin, sufficient to cause headache, confusion, dizziness and visual disturbance. [SEA91FA156]

October 1992. The pilot of Cessna 150 N6402S was in radio contact with the control tower at Mt. Gilead, Ohio, and in a descent from 5,000 feet to 2,000 feet in preparation for landing. Radar contact was lost, and the aircraft crashed into a wooded area, seriously injuring the pilot. Toxicological tests on the pilot’s blood were positive for carbon monoxide. Examination of the left muffler revealed three cracks and progressive deterioration. The NTSB found probable cause of the accident to be pilot incapacitation due to carbon monoxide poisoning. [NYC93LA031]

April 1994. Fifteen minutes after takeoff from Long Beach, Calif., the Cessna 182 N9124G began deviating from headings, altitudes and ATC instructions. The aircraft did several 360- and 180-degree turns. The pilot reported blurred vision, headaches, nausea, labored breathing, and difficulty staying awake. The aircraft ultimately crashed in a vineyard near Kerman, Calif., and the owner/pilot was seriously injured. Post-crash inspection revealed numerous small leaks in the exhaust system. The pilot tested positive for carbon monoxide even after 11 hours of oxygen therapy. [LAX94LA184]

October 1994. A student pilot returned to Chesterfield, Mo., from a solo cross-country flight in Cessna 150 N7XC, complaining of headache, nausea, and difficulty walking. The pilot was hospitalized, and medical tests revealed elevated CO which required five and a half hours breathing 100% oxygen to reduce to normal levels. Post-flight inspection revealed a crack in an improperly repaired muffler that had been installed 18 hours earlier. [CHI95IA030]

March 1996. The pilot of Piper Cherokee 140 N95394 stated that she and her passenger became incapacitated after takeoff from Pittsburg, Kan. The airplane impacted the terrain, but the occupants were uninjured. Both were hospitalized, and toxicological tests for carbon monoxide were positive. A subsequent examination found holes in the muffler. [CHI96LA101]

August 1996. A Mankovich Revenge racer N7037J was #2 in a four-airplane ferry formation of Formula V Class racing airplanes. The #3 pilot said that the #2 pilot’s flying was erratic during the flight. The airplane crashed near Jeffersonville, Ind., killing the pilot. The results of FAA toxicology tests of the pilot’s blood revealed a 41% saturation of carboxyhemoglobin; loss of consciousness is attained at approximately 30%. Examination of the wreckage revealed that the adhesive resin that bound the rubber stripping forming the firewall lower seal was missing. The NTSB determined probable cause of the accident to be pilot incapacitation due to carbon monoxide poisoning. [CHI96FA322]

January 1997. The fatal crash of Piper Dakota N8263Y near Lake Winnipesaukee, N.H. (described previously). [IAD97FA043]

December 1997. Non-fatal crash of Piper Comanche 400 N8452P flying from Hoisington to Topeka, Kansas (described previously). [CHI98LA055]

December 1997. A new Cessna 182S was being ferried from the factory in Independence, Kan., to a buyer in Germany when the ferry pilot felt ill and suspected carbon monoxide poisoning (described previously). [Priority Letter AD 98-02-05]

Overall, deaths from unintentional carbon monoxide poisoning have dropped sharply since the mid-1970s thanks mainly to lower CO emissions from automobiles with catalytic converters (most CO deaths are motor vehicle-related) and safer heating and cooking appliances. But CO-related airplane accidents and incidents haven’t followed this trend. The ADs issued against Independence-built Cessna 172s and 182s and Mooney Ovations demonstrates that even brand new airplanes aren’t immune.

CO Checklist

Click on image above for high-resolution printable version.

Close calls

In addition to these events in the NTSB accident database where CO poisoning was clearly implicated, there were almost certainly scores of accidents, incidents, and close calls where CO was probably a factor.

In January 1999, for example, a Cessna 206 operated by the U.S. Customs Service was on a night training mission when it inexplicably crashed into Biscayne Bay a few miles off the south Florida coast. The experienced pilot survived the crash, but had no recollection of what happened. The NTSB called it simple pilot error and never mentioned CO as a possible contributing factor. However, enough carboxyhemoglobin was found in the pilot’s blood that the Customs Service suspected that CO poisoning might have been involved.

The agency purchased sensitive industrial electronic CO detectors for every single-engine Cessna in its fleet, and discovered that many of the planes had CO-in-the-cockpit problems. On-board CO detectors and CO checks during maintenance inspections have been standard operating procedure for the Customs Service ever since.

How much CO is too much?

It depends on whom you ask.

EPA calls for a health hazard alert when the outdoor concentration of CO rises above 9 parts per million (ppm) for eight hours, or above 35ppm for one hour. OSHA originally established a maximum safe limit for exposure to CO in the workplace of 35 ppm, but later raised it to 50 ppm under pressure from industry.

The FAA requires that CO in the cabin not exceed 50 ppm during certification testing of new GA airplanes certified under FAR Part 23 (e.g. Cessna Corvallis, Cirrus SR22, Diamond DA-40). Legacy aircraft certified under older CAR 3 regs required no CO testing at all during certification.

Once certified, FAA requires no CO testing of individual aircraft by the factory, and no follow-up retesting during annual inspections. A March 2010 FAA SAIB (CE-10-19 R1) recommends checking CO levels with a hand-held electronic CO detector during ground runups at each annual and 100-hour inspection, but in my experience very few shops and mechanics do this.

UL-approved residential CO detectors are not permitted to alarm until the concentration rises to 70 ppm and stays there for four hours. (This was demanded by firefighters and utility companies to reduce the incidence of nuisance calls from homeowners.) Yet most fire departments require that firefighters put on their oxygen masks immediately when CO levels reach 25 ppm or higher.

It’s important to understand that low concentrations of CO are far more hazardous to pilots than to non-pilots. That’s because the effects of altitude hypoxia and CO poisoning are cumulative. For example, a COHb saturation of 10% (which is about what you’d get from chain-smoking cigarettes) would probably not be noticeable to someone on the ground. But at 10,000 feet, it could seriously degrade your night vision, judgment, and possibly cause a splitting headache.

After studying this hazard for many years and consulting with world-class aeromedical experts, I have come to the following conclusions:

  1. Every single-engine piston aircraft should carry a sensitive electronic CO detector.
  2. Any in-flight CO concentration above 10 ppm should be brought to the attention of an A&P for troubleshooting and resolution.
  3. Any in-flight CO concentration above 35 ppm should be grounds for going on supplemental oxygen (if available) and making a precautionary landing as soon as practicable.

Smokers are far more vulnerable to both altitude hypoxia and CO poisoning, since they’re already in a partially poisoned state when they first get into the aircraft. Because of COHb’s long half-life, you’d do well to abstain from smoking for 8 to 12 hours prior to flight.

Choosing a CO detector

Five CO detectors

Five CO detectors (left to right): chemical spot, UL-compliant residential (Kidde), non-UL-compliant (CO Experts 2015), industrial (BW Honeywell), TSO’d panel-mounted (CO Guardian 551).

Chemical spot detectors:Stay away from those ubiquitous el-cheapo adhesive-backed cardboard chemical spot detectors that are commonly sold by pilot shops and mail-order outfits for under trade names like “Dead Stop,” “Heads Up” and “Quantum Eye.” They have a very short useful life (about 30 days), and are extremely vulnerable to contamination from aromatic cleaners, solvents and other chemicals routinely used in aircraft maintenance.

These things often remain stuck on the instrument panel for years, providing a dangerous false sense of security. What’s worse, there’s no warning that the detector is outdated or has been contaminated—in some ways, that’s worse than not having a detector at all.

Even when fresh, chemical spot detectors are incapable of detecting low levels of CO. They’ll start turning color at 100ppm, but so slowly and subtly that you’ll never notice it. For all practical purposes, you’ll get no warning until concentrations rise to the 200 to 400 ppm range, by which time you’re likely to be too impaired to notice the color change.

Residential electronic detectors:Although battery-powered residential electronic detectors are vastly superior to those worthless chemical spots, most are designed to be compliant with Underwriter’s Laboratory specification UL-2034 (revised 1998). This spec requires that

(1)   The digital readout must not display any CO concentration less than 30 ppm.

(2)   The alarm will not sound until CO reaches 70 ppm and remains at or above that level for four hours.

(3)   Even at a concentration of 400 ppm, it may take as much as 15 minutes before the alarm sounds.

For aircraft use, you really want something much more sensitive and fast-acting. I like the non-UL-compliant CO Experts Model 2015 ($199 from www.aeromedix.com). It displays CO concentrations as low as 7 ppm and provides a loud audible alarm at concentrations above 25 ppm. It updates its display every 10 seconds (compared to once a minute for most residential detectors), which makes it quite useful as a “sniffer” for trying to figure out exactly where CO is entering the cabin.

Industrial electronic detectors:Industrial CO detectors cost between $400 and $1,000. A good choice for in-cockpit use is the BW Honeywell GasAlert Extreme CO  ($410 from www.gassniffer.com). This unit displays CO concentrations from 0 to 1,000 ppm on its digital display, has a very loud audible alarm with dual trigger levels (35 and 200 ppm).

Purpose-built aviation electronic detectors:Tucson-based CO Guardian LLC makes a family of TSO’d panel-mount electronic CO detectors specifically designed for cockpit use. These detectors detect and alarm at 50 ppm (after 10 minutes), or 70 ppm (after 5 minutes), and will alarm instantly if concentrations rise to 400 ppm. The digital display models ($599 and up) will show concentrations as low as 10 ppm. Available from www.coguardian.com. Obviously, panel-mount detectors cannot be used as a sniffer to locate the source of a CO leak.

For more information…

There is an outstanding October 2009 research paper titled “Detection and Prevention of Carbon Monoxide Exposure in General Aviation Aircraft” authored by Wichita State University under sponsorship of the FAA Office of Research and Technology Development. The paper is 111 pages long, and discusses (among other things):

  • Characteristics of CO-related GA accidents
  • Evaluation of CO detectors, including specific makes and models
  • Placement of CO detectors in the cabin
  • Exhaust system maintenance and inspection

This research paper is available online at:

http://www.tc.faa.gov/its/worldpac/techrpt/ar0949.pdf

Judgment, and the Day

Monday, August 18th, 2014

It was windy yesterday—blowing hard out of the south and gusting to near 40 knots, according to the anemometer mounted on the top of the FBO building that sits midfield at our little airport tucked into the Mad River Valley, near Warren, Vermont. Weather was inbound. But for the day conditions were still high overcast, with just a few scattered, scraggly cumulous. Nothing towering. Maybe some wave action from the wind flowing over the undulating Green Mountains and White Mountains to the south and east.

Sometimes it is better to be on the ground than in the air.

Sometimes it is better to be on the ground than in the air.

Definitely some turbulence.

All that, and I wanted to fly. No, seriously, I was aching to fly. Just two days before I’d had the opportunity to get back into a Schleicher ASK-21 two-place fiberglass sailplane. A sexy ship if there ever was one, with an excellent 40:1 glide ratio and plenty of capability (even for aerobatics, if you are skilled in that realm).

Sunday’s flight with Rick Hanson (who has been with Sugarbush Soaring so long no one I know can remember the place without him and his wife, Ginny) was all about re-familiarization. I’d flown a ship just like her the year before, in Minden, Nevada. Vermont’s conditions, on that Sunday, at least, were tame compared to the way I’d gotten my butt kicked by rising thermals and developing dust devils in the high Nevada desert. This year staying behind the tow plane, even boxing its wake was just an exercise, not a wrestling match.

Thermaling came back to me pretty quickly, too. Last year the thermals were leaning towers, tilting with the afternoon valley winds. This year, though they moved with the prevailing flow, they seemed a little wider. Finding that ball of rising air in the middle seemed easier, more intuitive. Maybe it is just that I’ve only let a year go by. Before Minden I’d had a two year hiatus from soaring. It could be that two years is just too long, leaving me just too rusty and out of practice.

In any case, by Monday’s flight I was feeling competent. My instructors that day were John and Jen, and they were a dream to fly with (as they all have been, really). It was an excellent day for soaring, with light winds and towering cumulous streets of clouds that did not over develop. One expert soaring pilot riding a capable steed made his way to Stowe, Vermont, and back. And yes, someone else called (actually he had his wife call for him, hmmm…) to ask for an aero-retrieve from 40 miles east. The good news was that he’d landed at an airport.

Landing out. That’s soaring-speak for not making it back to your point of origin. An aero-retrieve means you pay the tow plane to fly to you, and then give you a tow home. Some pilots combat this problem by flying a motor glider, firing up the engine when they get to the point where they are too low to return to their home base, perhaps because they misjudged the lift conditions, or how long the lift would hold out at the end of the day. Other pilots use better judgment to make sure they get back to home base every time.

My instructors on Monday spent plenty of time helping me “see” all of the possible acceptable off-airport landing sites in the valley, and just beyond. We were high enough to see the Adirondacks looming over Lake Champlain, and hear the Québécois’ French chatter in Canada, which I could see clearly to the north with every circle as I climbed to cloud base, rolled out, pushed over for speed, and commenced to glide to the next decent thermal.

We crossed the valley practicing wing-overs, crazy-eights, stalls and steep turns, until they felt I knew all the possible quirks of the fine machine I’d chosen to master. Landings required another skill—understanding that I was much closer to the ground at flare than in my usual ride, the RV-10. That took a bit of coaching, too, but ultimately I got the visual picture and our touchdowns were smooth and on the mark. The thing about sailplanes: though you can control your trajectory to landing nicely with dive brakes, you don’t get to go around if you come up short or long. Making it back to home base from altitude is all about calculating your inertia, choosing your descent speed, setting your trajectory with your dive brakes, and making your initial pattern entry point, downwind, base, final and landing spots on speed and on altitude. Add airport traffic into the mix and you’ve got a great scenario for teaching any pilot great judgment skills.

By day’s end on Monday I’d thermaled, reviewed primary skills, proven my pattern, landing, and even emergency landing prowess, and received my sign-off for solo in the ASK-21. Tuesday’s conditions, however, were nowhere near what I’d proved myself in, and I knew it. The sailplane sat ready for me at the end of the runway, and the tow plane pilot, Steve, eyed me, waiting to know what I wanted to do. The wind was whistling through the gaps in the window frame of the not-ready-for-winter FBO. Sure, I’d flown in some gnarly winds in Minden. But not solo. In fact the last time I’d soloed a glider was in benign conditions over flat land.

“Um…no. I’m not going up today,” I said definitively.

Steve smiled. Good call.

That afternoon I hiked up a cliffside to sit on a sheltered hunk of granite that provided me a view of  half the Champlain Valley. It wasn’t quite as splendid as my perch in the sailplane, but it did sooth. The clouds streamed by, harbingers of the rain that would follow. I was happy to be on terra firma, and ready to fly another day.

What Makes an Engine Airworthy?

Wednesday, July 2nd, 2014

If we’re going to disregard manufacturer’s TBO (as I have advocated in earlier blog posts), how do we assess whether a piston aircraft engine continues to be airworthy and when it’s time to do an on-condition top or major overhaul? Compression tests and oil consumption are part of the story, but a much smaller part than most owners and mechanics think.

Bob Moseley

James Robert “Bob” Moseley (1948-2011)

My late friend Bob Moseley was far too humble to call himself a guru, but he knew as much about piston aircraft engines as anyone I’ve ever met. That’s not surprising because he overhauled Continental and Lycoming engines for four decades; there’s not much about these engines that he hadn’t seen, done, and learned.

From 1993 and 1998, “Mose” (as his friends called him) worked for Continental Motors as a field technical representative. He was an airframe and powerplant mechanic (A&P) with inspection authorization (IA) and a FAA-designated airworthiness representative (DAR). He was generous to a fault when it came to sharing his expertise. In that vein, he was a frequent presenter at annual IA renewal seminars.

Which Engine Is Airworthy?

During these seminars, Mose would often challenge a roomful of hundreds of A&P/IA mechanics with a hypothetical scenario that went something like this:

Four good-looking fellows, coincidentally all named Bob, are hanging out at the local Starbucks near the airport one morning, enjoying their usual cappuccinos and biscotti. Remarkably enough, all four Bobs own identical Bonanzas, all with Continental IO-550 engines. Even more remarkable, all four engines have identical calendar times and operating hours.

While sipping their overpriced coffees, the four Bobs start comparing notes. Bob One brags that his engine only uses one quart of oil between 50-hour oil changes, and his compressions are all 75/80 or better. Bob Two says his engine uses a quart every 18 hours, and his compressions are in the low 60s. Bob Three says his engine uses a quart every 8 hours and his compressions are in the high 50s. Bob Four says his compressions are in the low 50s and he adds a quart every 4 hours.

Who has the most airworthy engine? And why?

Compression/Oil Level

Don’t place too much emphasis on compression test readings as a measure of engine airworthiness. An engine can have low compression readings while continuing to run smoothly and reliably and make full power to TBO and beyond. Oil consumption is an even less important factor. As long as you don’t run out of oil before you run out of fuel, you’re fine.

This invariably provoked a vigorous discussion among the IAs. One faction typically thought that Bob One’s engine was best. Another usually opined that Bobs Two and Three had the best engines, and that the ultra-low oil consumption of Bob One’s engine was indicative of insufficient upper cylinder lubrication and a likely precursor to premature cylinder wear. All the IAs agreed Bob Four’s was worst.

Mose took the position that with nothing more than the given information about compression readings and oil consumption, he considered all four engines equally airworthy. While many people think that ultra-low oil consumption may correlate with accelerated cylinder wear, Continental’s research doesn’t bear this out, and Mose knew of some engines that went to TBO with very low oil consumption all the way to the end.

While the low compressions and high oil consumption of Bob Four’s engine might suggest impending cylinder problems, Mose said that in his experience engines that exhibit a drop in compression and increase in oil consumption after several hundred hours may still make TBO without cylinder replacement. “There’s a Twin Bonanza that I take care of, one of whose engines lost compression within the first 300 hours after overhaul,” Mose once told me. “The engine is now at 900 hours and the best cylinder measures around 48/80. But the powerplant is running smooth, making full rated power, no leaks, and showing all indications of being a happy engine. It has never had a cylinder off, and I see no reason it shouldn’t make TBO.”

Lesson of a Lawn Mower

To put these issues of compression and oil consumption in perspective, Mose liked to tell the story of an engine that was not from Continental or Lycoming but from Briggs & Stratton:

Snapper Lawnmower

If this one-cylinder engine can perform well while using a quart of oil an hour, surely an aircraft engine with 50 times the displacement can, too.

Years ago, I had a Snapper lawn mower with an 8 horsepower Briggs on it. I purchased it used, so I don’t know anything about its prior history. But it ran good, and I used and abused it for about four years, mowing three acres of very hilly, rough ground every summer.

The fifth year I owned this mower, the engine started using oil. By the end of the summer, it was using about 1/2 quart in two hours of mowing. If I wasn’t careful, I could run out of oil before I ran out of gas, because the sump only held about a quart when full. The engine still ran great, mowed like new, although it did smoke a little each time I started it.

The sixth year, things got progressively worse, just as you might expect. By the end of the summer, it was obvious that this engine was getting really tired. It still ran okay, would pull the hills, and would mow at the same speed if the grass wasn’t too tall. But it got to the point that it was using a quart of oil every hour, and was becoming quite difficult to start. The compression during start was so low (essentially nil) that sometimes I had to spray ether into the carb to get the engine to start. It also started leaking combustion gases around the head bolts, and would blow bubbles if I sprayed soapy water on the head while it was running. In fact, the mower became somewhat useful as a fogger for controlling mosquitoes. But it still made power and would only foul its spark plug a couple of times during the season when things got really bad.

Now keep in mind that this engine was rated at just 8 horsepower and had just one cylinder with displacement roughly the size of a coffee cup, was using one quart of oil per hour, and had zilch compression. Compare that to an IO-550 with six cylinders, each with a 5.25-inch bore. Do you suppose that oil consumption of one quart per hour or compression of 40/80 would have any measurable effect on an IO-550’s power output or reliability—in other words, its airworthiness? Not likely.

In fact, Continental Motors actually ran a dynamometer test on an IO-550 whose compression ring gaps had been filed oversize to intentionally reduce compression on all cylinders to 40/80, and it made full rated power.

Common Sense 101Let’s Use Common Sense

I really like Mose’s commonsense approach to aircraft engines. Whether we’re owners or mechanics (or both), we would do well to avoid getting preoccupied with arbitrary measurements like compression readings and oil consumption that have relatively little correlation with true airworthiness.

Instead, we should focus on the stuff that’s really important: Is the engine “making metal”? Are there any cracks in the cylinder heads or crankcase? Any exhaust leaks, fuel leaks, or serious oil leaks? Most importantly, does the engine seem to be running rough or falling short of making full rated power?

If the answer to all of those questions is no, then we can be reasonably sure that our engine is airworthy and we can fly behind it with well-deserved confidence.

On-Condition Maintenance

The smart way to deal with engine maintenance—including deciding when to overhaul—is to do it “on-condition” rather than on a fixed timetable. This means that we use all available condition-monitoring tools to monitor the engine’s health, and let the engine itself tell us when maintenance is required. This is how the airlines and military have been doing it for decades.

Digital borescope (Adrian Eichhorn)

Digital borescopes and digital engine monitors have revolutionized piston aircraft engine condition monitoring.

For our piston aircraft engines, we have a marvelous multiplicity of condition-monitoring tools at our disposal. They include:

  • Oil filter visual inspection
  • Oil filter scanning electron microscopy (SEM)
  • Spectrographic oil analysis programs (SOAP)
  • Digital engine monitor data analysis
  • Borescope inspection
  • Differential compression test
  • Visual crankcase inspection
  • Visual cylinder head inspection
  • Oil consumption trend analysis
  • Oil pressure trend analysis

If we use all these tools on an appropriately frequent basis and understand how to interpret the results, we can be confident that we know whether the engine is healthy or not—and if not, what kind of maintenance action is necessary to restore it to health.

The moment you abandon the TBO concept and decide to make your maintenance decisions on-condition, you take on an obligation to use these tools—all of them—and pay close attention to what they’re telling you. Unfortunately, many owners and mechanics don’t understand how to use these tools appropriately or to interpret the results properly.

When Is It Time to Overhaul?

It takes something pretty serious before it’s time to send the engine off to an engine shop for teardown—or to replace it with an exchange engine. Here’s a list of the sort of findings that would prompt me to recommend that “the time has come”:

Lycoming cam and lifter

Badly damaged cam lobe found during cylinder removal. “It’s time!”

  • An unacceptably large quantity of visible metal in the oil filter; unless the quantity is very large, we’ll often wait until we’ve seen metal in the filter for several shortened oil-change intervals.
  • A crankcase crack that exceeds acceptable limits, particularly if it’s leaking oil.
  • A serious oil leak (e.g., at the crankcase parting seam) that cannot be corrected without splitting the case.
  • An obviously unairworthy condition observed via direct visual inspection (e.g., a bad cam lobe observed during cylinder or lifter removal).
  • A prop strike, serious overspeed, or other similar event that clearly requires a teardown inspection in accordance with engine manufacturer’s guidance.

Avoid getting preoccupied with compression readings and oil consumption that have relatively little correlation with true airworthiness. Ignore published TBO (a thoroughly discredited concept), maintain your engine on-condition, make sure you use all the available condition-monitoring tools, make sure you know how to interpret the results (or consult with someone who does), and don’t overreact to a single bad oil report or a little metal in the filter.

Using this reliability-centered approach to engine maintenance, my Savvy team and I have helped hundreds of  aircraft owners obtain the maximum useful life from their engines, saving them a great deal of money, downtime and hassle. And we haven’t had one fall out of the sky yet.

The Dark Side of Maintenance

Tuesday, June 10th, 2014

The Dark SideHave you ever put your airplane in the shop—perhaps for an annual inspection, a squawk, or a routine oil change—only to find when you fly it for the first time after maintenance that something that was working fine no longer does?  Every aircraft owner has had this happen. I sure have.

Maintenance has a dark side that isn’t usually discussed in polite company: It sometimes breaks aircraft instead of fixing them.

When something in an aircraft fails because of something a mechanic did—or failed to do—we refer to it as a “maintenance-induced failure”…or “MIF” for short. Such MIFs occur a lot more often than anyone cares to admit.

Why do high-time engines fail?

I started thinking seriously about MIFs in 2007 while corresponding with Nathan Ulrich Ph.D. about his ground-breaking research into the causes of catastrophic piston aircraft engine failures (based on five years’ worth of NTSB accident data) that I discussed in an earlier post. Dr. Ulrich’s analysis showed conclusively that by far the highest risk of catastrophic engine failure occurs when the engine is young—during the first two years and 200 hours after it is built, rebuilt or overhauled—due to “infant-mortality failures.”

But the NTSB data was of little statistical value in analyzing the failure risk of high-time engines beyond TBO, simply because so few engines are operated past TBO; most are arbitrarily euthanized at TBO. We don’t have good data on how many engines are flying past TBO, but it’s a relatively small number. So it’s s no surprise that the NTSB database contains very few accidents attributed to failures of over-TBO engines. Because there are so few, Ulrich and I decided to study all such NTSB reports for 2001 through 2005 to see if we could detect some pattern of what made these high-time engines fail. Sure enough, we did detect a pattern.

About half the reported failures of past-TBO engines stated that the reason for the engine failure could not be determined by investigators. Of the half where the cause could be determined, we found that about 80% were MIFs. In other words, those engines failed not because they were past TBO, but because mechanics worked on the engines and screwed something up!

Sheared Camshaft Bevel GearCase in point: I received a call from an aircraft owner whose Bonanza was undergoing annual inspection. The shop convinced the owner to have his propeller and prop governor sent out for 6-year overhauls. (Had the owner asked my advice, I’d have urged him not to do this, but that’s another story for another blog post.)

The overhauled prop and governor came back from the prop shop and were reinstalled. The mechanic had trouble getting the prop to cycle properly, and he wound up removing and reinstalling the governor three times. During the third engine runup, the the prop still wouldn’t cycle properly. The mechanic decided to take the airplane up on a test flight anyway (!) which resulted in an engine overspeed. The mechanic then removed the prop governor yet again and discovered that the governor drive wasn’t turning when the crankshaft was rotated.

I told the owner that I’d seen this before, and the cause was always the same: improper installation of the prop governor. If the splined drive and gears aren’t meshed properly before the governor is torqued, the camshaft gear is damaged, and the only fix is a teardown. (A couple of engine shops and a Continental tech rep all told the owner the same thing.)

This could turn out to be a $20,000 MIF. Ouch!

How often do MIFs happen?

They happen a lot. Hardly a day goes by that I don’t receive an email or a phone call from an exasperated owner complaining about some aircraft problem that is obviously a MIF.

A Cessna 182 owner emailed me that several months earlier, he’d put the plane in the shop for an oil change and installation of an STC’d exhaust fairing. A couple of months later, he decided to have a digital engine monitor installed. The new engine monitor revealed that the right bank of cylinders (#1, #3 and #5) all had very high CHTs well above 400°F. This had not shown up on the factory CHT gauge because its probe was installed on cylinder #2. (Every piston aircraft should have an engine monitor IMHO.) At the next annual inspection at a different shop, the IA discovered found some induction airbox seals missing, apparently left off when the exhaust fairing was installed. The seals were installed and CHTs returned to normal.

Sadly, the problem wasn’t caught early enough to prevent serious heat-related damage to the right-bank cylinders. All three jugs had compressions down in the 30s with leakage past the rings, and visible damage to the cylinder bores was visible under the borescope. The owner was faced with replacing three cylinders, around $6,000.

Sandel SN3308The next day, I heard from the owner of an older Cirrus SR22 complaining about intermittent heading errors on his Sandel SN3308 electronic HSI. These problems started occurring intermittently about three years earlier when the shop pull the instrument for a scheduled 200-hour lamp replacement.

Coincidence?

I’ve seen this in my own Sandel-equipped Cessna 310, and it’s invariably due to inadequate engagement between the connectors on the back of the instrument and the mating connectors in the mounting tray. You must slide the instrument into the tray just as far as possible before tightening the clamp; otherwise, you’ve set the stage for flaky electrical problems. This poor Cirrus owner had been suffering the consequences for three years. It took five minutes to re-rack the instrument and cure the problem.

Pitot-Static PlumbingNot long after that, I got a panicked phone call from one of my managed-maintenance clients who’d departed into actual IMC in his Cessna 340 with his family on board on the first flight after some minor avionics work. (Not smart IMHO.) As he entered the clag and climbed through 3,000 feet, all three of his static instruments—airspeed, altimeter, VSI—quit cold. Switching to alternate static didn’t cure the problem. The pilot kept his cool, confessed his predicament to ATC, successfully shot an ILS back to his home airport, then called me.

The moment I heard the symptoms, I knew exactly what happened because I’d seen it before. “Take the airplane back to the avionics shop,” I told the owner,  “and ask the tech to reconnect the static line that he disconnected.” A disconnected static line in a pressurized aircraft causes the static instruments to be referenced to cabin pressure. The moment the cabin pressurizes, those instruments stop working. MIF!

I know of at least three other similar incidents in pressurized singles and twins, all caused by failure of a mechanic to reconnect a disconnected static line. One resulted in a fatal accident, the others in underwear changes. The FARs require a static system leak test any time the static system is opened up, but clearly some technicians are not taking this seriously.

Causes of Accidents

Why do MIFs happen?

Numerous studies indicate that three-quarters of accidents are the fault of the pilot. The remaining one-quarter are machine-caused, and those are just about evenly divided between ones caused by aircraft design flaws  and ones caused by MIFs. That suggests one-eighth of accidents are maintenance-induced, a significant number.

The lion’s share of MIFs are errors of omission. These include fasteners left uninstalled or untightened, inspection panels left loose, fuel and oil caps left off, things left disconnected (e.g., static lines), and other reassembly tasks left undone.

Distractions play a big part in many of these omissions. A mechanic installs some fasteners finger-tight, then gets a phone call or goes on lunch break and forgets to finish the job by torqueing the fasteners. I have seen some of the best, most experienced mechanics I know fall victim to such seemingly rookie mistakes, and I know of several fatal accidents caused by such omissions.

Maintenance is invasive!

Whenever a mechanic takes something apart and puts it back together, there’s a risk that something won’t go back together quite right. Some procedures are more invasive than others, and invasive maintenance is especially risky.

Invasiveness is something we think about a lot in medicine. The standard treatment for gallstones used to be cholecystectomy (gall bladder removal), major abdominal surgery requiring a 5- to 8-inch incision. Recovery involved a week of hospitalization and several weeks of recovery at home. The risks were significant: My dad very nearly died as the result of complications following this procedure.

Nowadays there’s a far less invasive procedure—laproscopic cholecystectomy—that involves three tiny incisions and performed using a videoscope inserted through one incision and various microsurgery instruments inserted through the others. It is far less invasive than the open procedure. Recovery usually involves only one night in the hospital and a few days at home. The risk of complications is greatly reduced.

Similarly, some aircraft maintenance procedures are far more invasive than others. The more invasive the maintenance, the greater the risk of a MIF. When considering any maintenance task, we should always think carefully about how invasive it is, whether the benefit of performing the procedure is really worth the risk, and whether less invasive alternatives are available.

Ryan Stark of Blackstone LabsFor example, I was contacted by an aircraft owner who said that he’d recently received an oil analysis report showing an alarming increase in iron. The oil filter on his Continental IO-520 showed no visible metal. The lab report suggested flying another 25 hours and then submitting another oil sample for analysis.

The owner showed the oil analysis report to his A&P, who expressed grave concern that the elevated iron might indicate that one or more cam lobes were coming apart. The mechanic suggested pulling one or two cylinders and inspecting the camshaft.

Yikes! What was this mechanic thinking? No airplane has ever fallen out of the sky because of a cam or lifter problem. Many have done so following cylinder removal, the second most invasive thing you can do to an engine. (Only teardown is more invasive.)

The owner wisely decided to seek a second opinion before authorizing this exploratory surgery. I told him the elevated iron was almost certainly NOT due to cam lobe spalling. A disintegrating cam lobe throws off fairly large steel particles or whiskers that are usually visible during oil filter inspection. The fact that the oil filter was clean suggested that the elevated iron was coming from microscopic metal particles less than 25 microns in diameter, too small to be detectable in a filter inspection, but easily detectable via oil analysis. Such tiny particles were probably coming either from light rust on the cylinder walls or from some very slow wear process.

I suggested the owner have a borescope inspection of his cylinders to see whether the bores showed evidence of rust. I also advised that no invasive procedure (like cylinder removal) should ever be undertaken solely on the basis of a single oil analysis report. The oil lab was spot-on in recommending that the aircraft be flown another 25 hours. The A&P wasn’t thinking clearly.

Even if a cam inspection was warranted, there’s a far less invasive method. Instead of a 10-hour cylinder removal, the mechanic could pull the intake and exhaust lifters, and then determine the condition of the cam by inspecting it with a borescope through the lifter boss and, if warranted, probing the cam lobe with a sharp pick. Not only would this procedure require just 15% as much labor, but the risk of a MIF would be nil.

Sometimes, less is more

Many owners believe—and many mechanics preach—that preventive maintenance is inherently a good thing, and the more of it you do the better. I consider this wrongheaded. Mechanics often do far more preventive maintenance than necessary and often do it using unnecessarily invasive procedures, thereby increasing the likelihood that their efforts will actually cause failures rather than preventing them.
Mac Smith RCM Seminar DVDAnother of my earlier posts discussed Reliability-Centered Maintenance (RCM) developed at United Airlines in the late 1960s, and universally adopted by the airlines and the military during the 1970s. One of the major findings of RCM researchers was that preventive maintenance often does more harm than good, and that safety and reliability can often be improved dramatically by reducing the amount of PM and using minimally invasive techniques.

Unfortunately, this thinking doesn’t seem to have trickled down to piston GA, and is considered heresy by many GA mechanics because it contradicts everything they were taught in A&P school. The long-term solution is for GA mechanics to be trained in RCM principles, but that’s not likely to happen any time soon. In the short term, aircraft owners must think carefully before authorizing an A&P to perform invasive maintenance on their aircraft. When in doubt, get a second opinion.

The last line of defense

The most likely time for a mechanical failure to occur is the first flight after maintenance. Since the risk of such MIFs is substantial, it’s imperative that owners conduct a post-maintenance test flight—in VMC , without passengers, preferably close to the airport—before launching into the clag or putting passengers at risk. I think even the most innocuous maintenance task—even a routine oil change—deserves such a post-maintenance test flight. I do this any time I swing a wrench on my airplane.

You should, too.