Aviation Myths, Part 3

Is this dangerous?  Depends on the altitude, dude.

[For the rest of the series, see Part 1 or Part 2]

Myth #11: Aerobatics are dangerous.

Aerobatic flight has played a prominent part in many fatal accident reports. Sadly, that has given acro a bad name. A more thoughtful analysis, however, clearly shows that many — perhaps most — of those crashes are due to intentional low-altitude maneuvering. When aerobatic flying is pursued in a prudent, intelligent manner with sufficient altitude, the risks are far outweighed by the benefits.

Many fatalities come from the world of air shows. Air show flying can be extraordinarily dangerous because there’s virtually no structure or limit on what a pilot is permitted to do. As long as pilots don’t direct the energy of the aircraft toward spectators, a person holding a zero-altitude waiver can perform multiple outside snap rolls starting 1′ off the deck if they so choose. The flying is certainly dramatic, fun to watch, and a demonstration of complex skill. But pilots are free to fly without much, if any, altitude buffer. And many of them do.

Competitive aerobatics, on the other hand, is highly structured, limited, and categorized to the specific skill level of individual pilots. The altitude cushion is far higher and the safety record is much, much better. I’ve been involved in competitive aerobatics for eight years and know of only one accident during a competition.

The other category of accidents is people with inadequate training, experience, and/or equipment performing low-level aerobatics and buzzing terrain just to try and impress spectators or passengers. I’ve written extensively about why that’s a bad idea.

Speaking of buzzing, here’s a YouTube gem of a Bonanza and L-39 flying into IMC while in formation at low altitude. You’ll see the terrain flash by before the Beech loses part of the right wingtip in a tree.

Are you starting to see a pattern here? Low-altitude = high-risk. When you take out the low level stuff, aerobatics becomes a much different thing. There’s room the screw up a maneuver, laugh about it, fix it, and still be far above the ground. That’s safe. That’s sane.

I’m a big proponent of aerobatics because in my experience, nothing does more to build up a pilot’s stick-and-rudder skills and confidence than the precision, proficiency, and control demanded by quality aerobatic flight. An inadvertent spin, wake turbulence encounter, or other upset is far more likely to be handled properly by a pilot with aerobatic training. Aerobats are comfortable with full control deflections, odd sight pictures, high pitch/bank/yaw rates, accelerations, and sounds which can cause the straight-and-level crowd to freeze up, panic, or even worse, aggravate the situation with improper control inputs.

Myth #12: “Aerobatics” means exceeding 60 degrees of bank and/or 30 degrees of pitch.

Well 'chute!

This misconception is rampant among pilots. I’d say 85% of my primary acro students give me that definition when I ask about it early on in training. The FAA defines aerobatics in 14 CFR 91.303 as “an intentional maneuver involving an abrupt change in an aircraft’s attitude, an abnormal attitude, or abnormal acceleration, not necessary for normal flight.”

Notice how there are no specific bank or pitch angles attached to the definition? That’s why a 45 degree pitch angle after takeoff in a Cub would be considered aerobatic (it’s not necessary for normal flight), whereas flying solo in the Pitts S-2B, that same pitch angle would be just about right for holding a normal Vx climbout and therefore, NOT aerobatic in nature. The FAA’s definition is simple and elegant, yet also allows for the differing performance characteristics of each aircraft type.

The 60/30 degree thing comes from 14 CFR 91.307(c) and concerns parachutes, not aerobatics:

(c) Unless each occupant of the aircraft is wearing an approved parachute, no pilot of a civil aircraft carrying any person (other than a crewmember) may execute any intentional maneuver that exceeds—

(1) A bank of 60 degrees relative to the horizon; or

(2) A nose-up or nose-down attitude of 30 degrees relative to the horizon.

Myth #13: A spin in the pattern is unrecoverable.

This myth is demonstrably false. I’ve performed thousands of spins, and every plane I’ve spun eats up about 500′ of altitude from entry to recovery during a full 360 degree spin. Of course, that assumes the guy in the pilot seat can effect recovery properly and do so within 360 degrees of yaw. Might we have yet another argument for spin training? I think so.

I’m not suggesting you try a spin from a typical 1,000′ AGL pattern altitude. That would fall into the “low altitude follies” category of myth #11. But to say that a spin in the pattern is unrecoverable is just false. With even a little practice, it’s not hard to recover from an inadvertent spin in less than a quarter of a turn. That would eat up but a couple hundred feet of altitude and be more of a wing-drop than anything else.

I’d even go so far as to say that if you doubt your ability to stop a stall-spin entry from 1000′ AGL and recover to level flight before hitting the ground, you need to get some instruction before proceeding further. With sufficient training, the recovery technique will become virtually automatic. Idle power, full opposite rudder, lower the angle-of-attack.

Myth #14: Exceeding 30 degrees of bank in the pattern can lead to a stall/spin.

I was at an uncontrolled airport one day watching pilots do their thing, when a student pilot entered the pattern and announced her intention to land on runway 25. On her first attempt her Cherokee blew through the final approach course and she wisely went around. The next time she did the same thing. The third attempt was a larger pattern with an earlier turn to final which resulted in an undershoot. Trying to fix that, she allowed her glidepath to get too high. Another go-around.


By this point the student was pretty rattled and, I’m sure, more that a little embarrassed by her inability to land. You could hear it in her voice as she made various radio calls. After four or five attempts someone had to talk her down via the radio.

What the heck had happened, I wondered? Was there an abnormally high wind aloft just pushing her through the final? Was she turned loose by her instructor with insufficient training? Perhaps there was a mechanical problem with the airplane. Was the traffic on the CTAF too distracting? Maybe she was from a quiet country airport (as if we have any of those in Southern California…).

Further investigation revealed that her CFI had taught her not to exceed some arbitrary bank angle in the pattern. I don’t remember if it was 20 degrees or 30. Maybe it was 15. The exact figure is not important. This poor lady’s instructor had told her that the way to avoid an inadvertent spin in the pattern was to limit her bank angle.

For a long time I thought her CFI’s instruction was terrible, but thankfully not common. Unfortunately that’s starting to change. I even see this kind of advice provided by AOPA in their publications now! A quick Google search turned up an AOPA Safety Publication where the author suggests limiting base-to-final turns to as little as 15 degrees.

I am in agreement with teaching 30-degree banked turns in the pattern, for all the reasons mentioned. But I make an exception for the turn from base to final. The pilot flying this traffic pattern has begun his turn early, using a much shallower bank–perhaps 15 to 20 degrees. The result is a somewhat sloppier-looking, but safer, pattern. It gives the pilot more time to assess the effect of any crosswind and adjust his turn to smoothly intercept the final approach course. Because he starts the turn to final with a shallow bank angle, he can safely increase his bank (within limits) to counter an overshoot. Likewise, there should be little reason to tempt the pilot to skid. Even if he does, at the shallower bank this is much less likely to result in disaster. Check out the stall speed versus bank chart in your aircraft’s flight manual. Although a pilot who increases his bank from 30 degrees to 45 degrees and one who increases it from 15 to 30 are both increasing by the same number of degrees; the effect on stall speed is much more dramatic in the first case.

The stall speed only changes if one is maintaining level altitude flight during the turn. Who makes a base-to-final turn like that? The bottom line on this issue is that it’s wrong to attach a specific bank angle to safe flying or spin avoidance, regardless of whether it’s in the pattern or elsewhere. Maintain the same load factor on the airplane during the turn and the stall speed doesn’t change whatsoever!

You can spin a plane from wings-level flight. That how most intentional spins are performed, actually. Likewise, you can continuously bank a plane a full 360 degrees, turning in the opposite direction while you do so, and neither spin or stall. It’s called a rolling turn — a competitive aerobatic maneuver.

Let’s go over it one more time: spins are only possible if the airplane is allowed to exceed the critical angle-of-attack while in an uncoordinated state. It has absolutely nothing to do with airspeed, bank angle, altitude, or proximity to the traffic pattern or runway. If the poor girl flying that Cherokee had been properly taught, she would have avoided tremendous stress, embarrassment, and risk.

Myth #15: Flying is difficult.

This last one is for the non-pilots. I wish I could tell you that it takes super-human effort to fly, that only a steely-eyed genius with hand/eye coordination even the best video game gurus could never hope to possess can operate an aircraft. That’s what many passengers seem to think.

Alas, the truth is that physically flying most airplanes is not hard. Landing can be a bit of a challenge, especially if your standards are high and you want to nail it every time. But the taxi, takeoff, climb, cruise, and descent are pretty easy. I’ve had total neophytes do all the flying on many occasions. I’d only take over for the last few seconds before landing. It’s just not that hard.

Now, learning the regulations, aerodynamics, aircraft systems, meteorology, navigation, emergency procedures, signage, ATC communication, aeromedical factors, decision making, performance calculations, and the dozen other areas one must master in order to fly in today’s world? That’s a bit tougher. But the physical act of flying an airplane is not as hard as aviators would like to make you think.

Aviation Myths, Part 2

Obtaining a pilot certificate in only 40 hours is virtually impossible in today's complex aircraft.

[For the first five myths, see Part 1]

Myth #6: Only an FAA-certificated mechanic can perform maintenance on an airplane.

This myth can cost you — big time. A typical GA maintenance facility can charge $100 per hour, and aircraft spend far more time in the shop than even the most maintenance-prone automobiles. Do the math and you’ll see that, especially if you don’t fly your airplane at least a couple hundred hours per year, maintenance can easily top all other ownership costs combined. Why pay that much when you can do much of the work yourself?

Experts agree: Aircraft owners who studiously and routinely do some basic maintenance themselves, rather than waiting for the 100-hour or annual inspection, not only might save money in the long run by averting major repairs, but also reduce the aircraft’s down time, fly more safely, and learn valuable information about their airplane, which makes them better able to detect and troubleshoot problems that arise during the preflight.

Appendix A in Part 43 of the Federal Aviation Regulations includes a long list of major alterations and repairs reserved for certified mechanics. Also listed there are 32 preventive-maintenance chores that certified pilots can tackle themselves as long as they own the airplane, it isn’t flown commercially, and the maintenance doesn’t involve “complex assembly.”

These chores range from changing tires, servicing shock struts, and simple lubrication, to repairing broken landing-light wiring circuits, cleaning and replacing spark plugs, servicing and replacing batteries, and making simple repairs to cowlings and farings. If you do perform any such tasks, you must have the appropriate maintenance and service information at your fingertips.

Just do it.

The 32 preventative maintenance tasks cover the vast majority of everyday jobs you’d be paying a mechanic $100/hour to do. The full list includes some surprisingly critical items: fabric skin repair, replacing windows, changing out fuel lines, hoses, and filters, servicing wheel bearings, and painting the airframe. Better yet, if you can find a certified Airframe & Powerplant mechanic who is willing to supervise your work, there’s virtually no task you cannot legally perform.

I used to participate in the annual inspection of my aircraft, and it not only saved me money, but the “hands on” aspect of swinging wrenches on the plane taught me more than any book or class ever could about what goes on under the cowling.

Myth #7: Shock-cooling an air-cooled piston powerplant causes premature wear, engine damage, IRS audits, and the defeat of your favorite sports team.

When I was working on my commercial pilot certificate, I was taught that power reductions of more than 2″ MP per minute were verboten due to shock cooking, the concept that if the engine cooled too quickly, the hottest part of the top end could warp or crack. Myth or reality?

The bottom line on shock cooling is that yes, it does exist. It’s scientifically provable. If you heat a thin slice of metal to several thousand degrees and then plunge it into a tub of sub-zero water, it will warp if not crack. But aircraft engines do not operate at such temperature extremes and generally cannot be cooled quickly enough to cause damage of that severity.

Shock cooling: myth or reality?

The closest thing we’ve got to those extremes might be a skydiving operation where an aircraft departs at heavy weight and climbs to altitude, drops the skydivers, and then makes a long fast descent at idle power. They’ve been doing it for decades and you don’t see any jump planes falling out of the air.

Aerobatic aircraft powerplants are probably the most highly stressed and badly abused engines in the sky. Slamming the throttle from full power to idle, over and over again. Rapid shifts from high power/no airspeed to low power/high airspeed. Heavy G loads, odd stresses on the crankshaft from propeller-induced gyroscopics. In my experience, those engines don’t seem to suffer from shock cooling any more than they do from other forms of hard living.

This one has been thoroughly debunked by people who are far better versed in the care and feeding of reciprocating aircraft engines than myself. I recommend the following reading:

Kas Thomas: Shock Cooling, Myth or Reality?
John Deakin: Pelican’s Perch #36

Myth #8: You can become a pilot with just 40 hours of flight time!

Flight training providers are for-profit companies who rely, in part, on advertising to find their customers. It’s understandable that they want to make flight training as appealing as possible. However, it’s short-sighted to advertise a pilot certificate based on the legal minimum of 40 hours.

Obtaining a pilot certificate in only 40 hours is virtually impossible in today's complex aircraft.

Can it be done? Yes, it’s possible, but only a miniscule percentage of aviators complete their training in that time. The national average is now over 70 hours.

There are several reasons for this. For one thing, the regulatory minimum of 40 hours has been in place for decades. Back then, airspace was simpler, there were fewer regulations, no TFRs, and society in general was less litigious. Today, we have ballistic parachutes, wake turbulence procedures, computerized flight displays, additional training requirements, more complex aircraft, and a far lower tolerance for risk than they did fifty years ago.

The 40 hour minimum remains on the books, but don’t think that you’ll be a properly trained pilot in that time unless you come to the table with a high level of aptitude, plenty of drive, and can train intensively. Oh, and you’ll want to fly a simple airplane (Citabria, anyone?) out of a quiet airport.

Myth #9: Stalls and airspeed are related.

To my mind, this is one of the most dangerous misconceptions in aviation. Airline accidents like Air France 447 and Colgan 3407 can be traced to it, as can hundreds of GA crashes.

I wish this one was relegated to students or flight simmers, but it’s not. Most pilots equate stalls with low airspeed, but in reality the two are unrelated. The pilot most likely to have a proper understanding of the relationship between stalls and airspeed isn’t the professional airline pilot with 20,000 hours in his logbook, it’s the guy who flies competitive aerobatics, because they see the extremes of the envelope again and again.

It's all about angle-of-attack, not airspeed!

An aircraft’s stall speed will vary — sometimes dramatically — with load factor, weight, CG location, and other factors. What does not change is the relationship between stall and angle of attack. Any airfoil will stall at the same angle of attack. When you exceed that AoA, it stalls regardless of your airspeed. Aircraft can be flown at any airspeed without stalling (even 1 knot!). Likewise, any aircraft can be stalled at any airspeed up to and beyond Vne.

Think about that the next time you’re looking at that red radial line on the lower end of your airspeed indicator. We may refer to that as the plane’s “stall speed”, but it’s only valid on a clean, new airframe flying at very specific weight and CG location under a 1g load. Change any of those factors and the airplane will stall at a different airspeed.

Myth #10: Tailwheel airplanes are not worth the difficulty and hassle.

Tailwheels — airplanes with the main landing gear located in front of the center of gravity and a small third wheel under the tail — make great pilots because they have to be better in order to operate them safely. That’s a good thing.

Sure, they have plenty of negatives: they’re highly unstable on the ground, suffer from limited forward visibility (if they have any at all!), typically have weak brakes, and they’re more vulnerable to wind due to the built-in angle of attack when on the ground.

The advantages? There must be some reason they keep building them, after all. How about better prop clearance, shorter takeoff and landing rolls, lighter weight and less drag than a tricycle gear configuration, tighter turning radius, and simpler, less expensive, more durable construction?

Beautiful, historic, and fun to fly. What's not to like?

However, the big bonus a tailwheel provides is the serious upgrade in good old fashioned stick-and-rudder skill you get from flying one. No more dropping the plane onto the runway with the nose pointed who-knows-where and rolling out more as a passenger than a pilot. With a tailwheel, you learn to keep it straight, stop any drift, pay serious attention to where the wind is coming from, and most of all keep flying the airplane all the way to a full stop.

It’s worth pointing out that you needn’t fly a conventional gear aircraft to become proficient at landing an airplane. Truth be told, the exact same technique is used to land GA aircraft regardless of landing gear type. But the tricycle gear configuration is far more tolerant of sloppy technique, and people tend to use only as much skill as is necessary for the aircraft they’re flying. As an instructor I’ve been guilty of it myself, demanding a higher level of performance from a Pitts student than one flying a DiamondStar. In an ideal world, I’d require the same high quality landings from both candidates.

According to the Air Safety Foundation, takeoff and landing phases of flight are where the vast majority of aircraft accidents occur, and the skill developed by taming a taildragger can be put to use flying any airplane regardless of size. They can be a handful, but I was convinced years ago that these wonderful aircraft can do more than anything else to eliminate takeoff and landing accidents, not cause them.

[… continue reading in Part 3]

Aviation Myths, Part 1


Over the past decade and a half I’ve been keeping a mental list of frequently encountered misconceptions about flying. For some reason, I recently Googled “aviation myths” and found quite a few articles on the topic and it inspired me to finally set my own list to virtual “paper”.

This list is not exhaustive, but it does represent the myths I encounter most frequently. Some of these are misconceptions held by non-pilots, others are more common among student aviators or even experienced professionals. I’ve written about a few of these in the past, but thought it might be worthwhile to throw the whole list out there for others to chew on. I’m planning to make this a three-part series, with five myths per post.

Have you encountered any of these before? Do you disagree with any of them? If so, I’d love to get your feedback. OK, here we go!

Myth #1: Logging “actual IMC” is only allowed when flying in clouds or low visibility.

Some aviation myths and misconceptions are absurd while others are entirely understandable. This one falls into the latter category. Even a non-pilot would find it logical to assume that logging flight time in the “actual IMC” column would require one to actually fly in instrument meteorological conditions (IMC). Thankfully for those of you who are attempting to build instrument time, it ain’t necessarily so.

14 CFR 61.51(g) states that “A person may log instrument time only for that flight time when the person operates the aircraft solely by reference to instruments under actual or simulated instrument flight conditions.” In other words, any time conditions are such that maintaining control of the aircraft by outside visual reference is in serious doubt and the instruments are used in lieu of those references, one may log actual IMC flight time.

The classic example of this situation is flying on a dark, moonless night over unlighted terrain (desert, ocean, mountains, etc). If John F. Kennedy, Jr. had realized this, he might be alive today. He took off from New York and headed toward the island of Martha’s Vineyard on just such a night. The reported and actual visibility was far above VFR minimums. In fact it was a CAVU night. Unfortunately, without any discernible horizon to look at, his situation required flying on the instruments. It’s not something primary or instrument instructors often pass along to their students, but we should.

If my word isn’t sufficient on this issue, here’s an excerpt from an FAA legal opinion issued by the agency’s Assistant Chief Counsel.

As you know, Section 61.51(c)(4) provides rules for the logging of instrument flight time which may be used to meet the requirements of a certificate or rating, or to meet the recent flight experience requirements of Part 61. That section provides in part, that a pilot may log as instrument flight time only that time during which he or she operates the aircraft solely by reference to instruments, under actual (instrument meteorological conditions (imc)) or simulated instrument flight conditions.

“Simulated” instrument conditions occur when the pilot’s vision outside of the aircraft is intentionally restricted, such as by a hood or goggles. “Actual” instrument flight conditions occur when some outside conditions make it necessary for the pilot to use the aircraft instruments in order to maintain adequate control over the aircraft. Typically, these conditions involve adverse weather conditions.

To answer your first question, actual instrument conditions may occur in the case you described a moonless night over the ocean with no discernible horizon, if use of the instruments is necessary to maintain adequate control over the aircraft. The determination as to whether flight by reference to
instruments is necessary is somewhat subjective and based in part on the sound judgment of the pilot.

Note that, under Section 61.51(b)(3), the pilot must log the conditions of the flight. The log should include the reasons for determining that the flight was under actual instrument conditions in
case the pilot later would be called on to prove that the actual instrument flight time logged was legitimate.

I have logged actual IMC this way. Once you leave the Los Angeles basin, flying over the desert southwest on moonless nights can necessitate being on the gauges every bit as much as flying in a cloud. Even if there is some moonlight or a small town out there, the ambient light put out by today’s glass panels can obliterate the view out the windscreen. In those cases it’s completely legitimate and proper to claim that time in your logbook.

Myth #2: Flying without appropriate charts is illegal.

In my experience, this is one of the most pervasive myths out there. As with logging actual IMC, it makes sense. Why wouldn’t the FAA require pilots to carry current versions of whatever pertinent charts applied to their route of flight?

Answer: 14 CFR 91.103 already requires pilots to becoming familiar with “all available information” concerning a flight. How an aviator obtains that information is up to them. Simply requiring a person to carry a large folded piece of paper isn’t going to necessarily familiarize them with anything. Believe me, as an instructor, I see that truism put to the test every day. I’ve seen pilots with a 14″ color moving map display have absolutely no idea where they were or where they were going.

As far as the charts are concerned, the FAA details their policy on chart carriage on their web site.

The subject of current charts was thoroughly covered in an article in the FAA’s July/August 1997 issue of FAA Aviation News. That article was cleared through the FAA’s Chief Counsel’s office. In that article the FAA stated the following:

“You can carry old charts in your aircraft.” “It is not FAA policy to violate anyone for having outdated charts in the aircraft.”

“Not all pilots are required to carry a chart.” “91.503..requires the pilot in command of large and multiengine airplanes to have charts.” “Other operating sections of the FAR such as Part 121 and Part 135 operations have similar requirements.”

…”since some pilots thought they could be violated for having outdated or no charts on board during a flight, we need to clarify an important issue. As we have said, it is NOT FAA policy to initiate enforcement action against a pilot for having an old chart on board or no chart on board.” That’s because there is no regulation on the issue.

…”the issue of current chart data bases in handheld GPS receivers is a non-issue because the units are neither approved by the FAA or required for flight, nor do panel-mounted VFR-only GPS receivers have to have a current data base because, like handheld GPS receivers, the pilot is responsible for pilotage under VFR.

“If a pilot is involved in an enforcement investigation and there is evidence that the use of an out-of-date chart, no chart, or an out-of-date database contributed to the condition that brought on the enforcement investigation, then that information could be used in any enforcement action that might be taken.”

If you, as an FAA Safety Inspector, Designated Pilot Examiner, Flight Instructor, or other aviation professional are telling pilots something other than the foregoing then you are incorrect.

From a practical standpoint, some airplanes like the Pitts S-1 are so small that there’s no place to carry a chart. Even if you wanted to use one, how would you do so when the airplane is about as stable as an Robinson R-22 in a hover? Can you imagine the pilot of a Cri-Cri or BD-5J trying to use a chart while in flight?

I’m not discouraging chart usage. Quite the contrary, I carry them myself. In fact, there are times when it is legally required. The aforementioned Part 121, 135, and 91 Large Airplane rules call for it when flying under those regulations. Some Class B VFR airspace transitions require a current terminal chart (the LA Special Flight Rules Area comes to mind). But for the most part, they are not legally required for Part 91 operators, even when flying under IFR!

Myth #3: Perfect eyesight is a requirement to be a pilot.

This one is a holdover from the days when most pilots came from the ranks of the military, which did require perfect eyesight. Even today most branches of the military require 20/20 vision (or better) for pilot candidates (helicopter requirements are occasionally a bit less stringent). But even they will allow for corrective lenses in many cases once they’ve invested the seven figure sums that it requires to transform a person into a mission-qualified aviator.

The FAA’s vision requirement for civilians is — and has been for many years — that a pilot’s eyesight be correctable to 20/40 for non-professional aviators. Those requiring a first- or second-class medical certificate must be correctable to 20/20 for distant vision and 20/40 for near vision.

Color blind? No problem. You can still fly with virtually no restrictions. In fact, you can obtain a medical certificate even if you’ve only got one eye. Pilots can get medical clearance after major brain surgery. While on anti-depressants. After heart and other organ transplants. You can even fly if you’re completely deaf! I’m aware of at least one pilot, a woman named Jessica Cox, who has no arms and still flies her aircraft solo. She demonstrated that she could do everything necessary to safely operate the aircraft using only her feet.

These days, you can fly gliders and Light Sport aircraft without any medical certificate at all. Old airport codgers may complain about how things ain’t the way they used to be, but in this case that’s a good thing.

Myth #4: TBO is mandatory.

Time-between-overhaul intervals are not well understood by most aircraft owners. For one thing, while most pilots understand that manufacturers establish a recommended hourly interval between major overhauls, they are often unaware that overhaul is also recommended once it reaches 12 years of age. This is important because most mechanics will tell you that the greatest enemy of piston aircraft engines is lack of use. One of the easiest ways to maximize engine life is to simply fly the plane frequently. This ensures the oil is brought up to operating temperature, any water in the system is boiled off, and the internal parts of the engine are coated in a protective layer of oil.

For non-commerical operators, TBO intervals are simply recommendations. There is no legal requirement to overhaul an engine at any time. Nor does exceeding TBO void insurance or warranty coverage. Plenty of people take published TBO intervals with a grain of salt, preferring instead to allow oil consumption, spectrographic oil analysis, borescope inspections, and other such metrics dictate when the engine is ready for overhaul.

Even commercial operators don’t necessarily have to overhaul at TBO. The FAA often grants extensions to those intervals by as much as 50% or more.

Myth #5: Repairs must always be accomplished using FAA-approved parts.

Let’s say you’re fortunate enough to fly an original 1917 Sopwith F-1 Camel — one of the preeminent fighters of the first World War. Where are you supposed to go for parts? They stopped manufacturing them nearly a century ago.

Okay, that’s an extreme example. But there are plenty of orphaned aircraft types still flying. Even among those that are still supported, parts can be exorbitantly expensive, even to the point of rendering an otherwise fine aircraft economically unfeasible to maintain.

Thankfully, 14 CFR 21.303(b)(2) and 21.9 allow owners of an aircraft — any aircraft, not just a vintage warbird — to manufacture parts for their airplane or pay someone to make them as long as the replacement part is identical to the original. The only caveat is that the owner must participate in the manufacture of the part by providing specifications, design information, quality control, materials, and/or supervising the fabrication of the item.

A personal example: a Pitts S-2B in which I share ownership needed a new seat back for the pilot’s seat. The old one was cracked and slowly failing after years of hard aerobatics. Now this is literally a flat rectangular piece of half-inch plywood with wood blocks attached to the back side to hold it in place. No fancy curves, shapes or fasteners. Just a plain old piece of wood. As I recall, the manufacturer of the Pitts series of biplanes, Aviat, wanted something close to thousand bucks for that part. We were able to manufacture one for a few dollars.

If you’re the kind of person who’s handy and has access to the proper tools, you can manufacture any part for your aircraft. A wing spar, a new crankcase, a propeller, and anything in between. If you’re not so handy? You can still hire a machinist, friend, or virtually anyone else to make the article as long as you materially participate in the process and create a part that is identical to the original in form and function — in other words, “airworthy”.

EAA posted an 85-minute video last August entitled “Owner Produced Parts for Certificated Aircraft” which covers this topic in great detail.

[… continue reading in Part 2]