The A&P Exam

Although I’ve been an aircraft owner since the late 1960s and heavily involved in GA maintenance since the late 1980s, I didn’t actually become an official card-carrying A&P mechanic until 2001. By the time I decided to go for my A&P ticket, I was already a pretty seasoned aircraft mechanic with a reputation for encyclopedic knowledge of aircraft systems and an aptitude for being able to troubleshoot thorny maintenance issues that had other mechanics stumped. I figured that passing the A&P exam would be a piece of cake.

I figured wrong.

An applicant for an A&P certificate must take and pass three multiple-choice 100-question knowledge tests.

An applicant for an A&P certificate must take and pass three multiple-choice 100-question knowledge tests.

By way of background, an applicant for an A&P certificate must surmount three sequential FAA-imposed hurdles. First, the applicant must prove to his FSDO that he has the minimum required experience performing maintenance on civil aircraft: 30 months on a full-time basis, or 4,800 hours on a part-time basis. Second, the applicant must take and pass three multiple-choice 100-question knowledge tests—mechanic general, mechanic airframe, and mechanic powerplant—and score at least 70% on each one. Third, the applicant must submit to an exhaustive (not to mention exhausting) oral and practical test with a Designated Mechanic Examiner—the mechanic’s equivalent to a checkride—which is normally at least a full-day affair.

When I started studying for the three A&P knowledge tests, my first surprise was the study syllabus, which struck me as being firmly anchored in the 1940s. For example, in preparing for the powerplant test, I reviewed more than 1,000 multiple-choice questions from the FAA’s “question bank” and found that the overwhelming emphasis was on radial engines, pressure carburetors, Hamilton Standard hydramatic propellers, and similar subjects of unquestionable interest to warbird buffs but of absolutely no relevance to contemporary GA aircraft of the sort that interested me. There were only a handful of questions about horizontally-opposed engines, perhaps two or three about fuel injection, only one about modern Hartzell compact hub propellers, and nothing at all about McCauleys.

The question bank for the powerplant test contained not a syllable about any technology that was less than 30 years old. Nothing about engine monitor data analysis, borescope inspections, spectrographic oil analysis, or scanning electron microscopy of oil filter contents. Nothing about compression ignition (Diesel) engines or electronic ignition systems or FADECs or lean-of-peak operation. Similarly, the airframe test was devoid of questions about composite construction (unless you count wood and fabric, which I suppose is the original composite).

To be fair to the FAA, there were actually lots of questions about “modern” 1960-vintage technologies, but they were all related to turbine and transport aircraft. To score a decent grade on the tests, it was obvious that I would need to master lots of material about turboprop and turbojet engines, air cycle machines, Roots blowers, and other esoterica that I knew I’d never remember or have any use for once the test was done.

Mastering the wrong answers

I took my three A&P knowledge tests at a local computerized testing center.

I took my three A&P knowledge tests at a local computerized testing center.

This was frustrating enough, but what really bugged me was that the “official FAA answer” to many of these multiple-choice questions was often the wrong answer. It became obvious that if I wanted to get a good score on the mechanic knowledge tests, I’d have to commit these “FAA answers” to memory even though I knew that they were the wrong answers.

Would you like to see some examples? Here are some actual questions from the 2001 FAA mechanic exam question bank, with the “official FAA answer” that would be used by the FAA to grade the exam:

#8072. Which fuel/air mixture will result in the highest engine temperature (all other factors remaining constant)?

A—A mixture leaner than a rich best-power mixture of .085.

B—A mixture richer than a full-rich mixture of .087.

C—A mixture leaner than a manual lean mixture of .060.

FAA-approved answer: C.

Discussion: Stoichiometric mixture (peak EGT) is around 15:1 or .067, so the FAA-approved answer C (“leaner than .060” or about 17:1) would be very lean-of-peak, far leaner than most engines can run without unacceptable roughness (unless they are fuel-injected and have tuned fuel nozzles). This is definitely a mixture at which the engine would run cool, not hot. Of the three choices given, the “most correct answer” is A. The FAA-approved answer (C) is just plain wrong, and perpetuates the Old Wives’ Tale that rich mixtures are cool and lean mixtures are hot. With training like this, is it any wonder so many A&Ps blame almost every cylinder malady to LOP operation?

#8678. Why must a float-type carburetor supply a rich mixture during idle?

A—Engine operation at idle results in higher than normal volumetric efficiency.

B—Because at idling speeds the engine may not have enough airflow around the cylinder to provide proper cooling.

C—Because of reduced mechanical efficiency during idle.

FAA-approved answer: B

Discussion: None of the given answers is correct, but the FAA-approved one is the probably the worst possible choice, because it suggests that pilots should keep the mixture full-rich during idle and taxi in order to obtain proper cooling. Do you suppose that OWT explains why so many pilots taxi around at full-rich and foul the crap out of their spark plugs? Are they learning this from their A&Ps? Here’s the correct answer: “Because a very rich mixture is required for cold-starting, and aircraft carburetors don’t have a choke to provide such a rich mixture (the way automotive carbs do), so the idle mixture has to be set extremely rich … which is why as soon as the engine starts to warm up, you need to come back on the mixture control.” Of course, that answer isn’t one of the choices offered.

#8773. Carburetor icing is most severe at…

A—air temperatures between 30 and 40 degrees F.

B—high altitudes.

C—low engine temperatures.

FAA-approved answer: A

Discussion: Are you kidding me? The AOPA Air Safety Foundation briefing on carb ice states, “Icing is most likely to occur—and to be severe—when temperatures fall roughly between 50°F and 70°F and the relative humidity is greater than 60%.” It shows a gory photo of the fatal crash of a Cessna 182 caused by carb ice that formed at OAT 80°F and dewpoint 45°F. If the FAA genius who wrote this question was a pilot, it’s a sure bet that most of his experience is flying Gulfstreams, not Skylanes. (Keep in mind that to get a decent grade on the A&P knowledge test, you have to memorize these FAA-approved wrong answers, or risk failing!)

#8829. Which of the following defects would likely cause a hot spot on a reciprocating engine cylinder?

A—Too much cooling fin area broken off.

B—A cracked cylinder baffle.

C—Cowling air seal leakage.

FAA-approved answer: A

Discussion: Once again, the FAA offers three possible answers and then claims that the “wrongest” one is the one they consider correct. Every IA I’ve asked agrees with me that by far the most likely cause is a bad baffle (answer B), and none has ever seen a case where a cooling fin was broken off badly enough to create an issue.

#8982. If a flanged propeller shaft has dowel pins…

A—install the propeller so that the blades are positioned for hand propping.

B—the propeller can be installed in only one position.

C—check carefully for front cone bottoming against the pins.

FAA-approved answer: B

Discussion: Well that’s interesting. The Continental TSIO-520-BB engines on my 1979 Cessna T310R have flanged propeller shafts. Each flange has a pair of identical dowel pins spaced 180° apart. This permits my three-bladed McCauley C87 props to be installed in two possible orientations, one that results in the vertical blade pointing down when the engine stops, and the other that results in the vertical blade pointing up. According to the Cessna service manual, only one of these orientations is the correct one, so you need to be careful when installing the prop. The FAA-approved answer (B) is just plain wrong. So are the other two answers.

I could go on, but you get the idea.



Here’s irrefutable proof that I was able to remember all those FAA-approved wrong answers long enough to score 96, 99 and 99 on my three mechanic knowledge tests.

Well, it took me many hours of study, practice and drill to memorize all of the FAA-approved wrong answers to the thousands of multiple-choice questions in the question bank. As you can imagine, going through this mind numbing exercise was a character-building experience that greatly expanded my vocabulary (of expletives) and bolstered my respect for the cutting-edge mindset of our favorite friendly federal agency.

I guess I must’ve done a workmanlike job of studying and memorizing, because when I finally took the three FAA knowledge tests at my “Don’t try this at home, kids” LaserGrade computerized testing center, I scored 96% on the general and 99% on both the airframe and powerplant. (See Figure 1.) I don’t want to brag, but it’s a rare skill to master so many wrong answers so consistently in such a short period of time, if I do say so myself.

Once the exams were done and my scores were in the bag, I celebrated with the obligatory overnight soak of my brain’s medial temporal lobe (seat of long-term memory) in a 50-50 mixture of cheap champagne and methyl ethyl ketone, just to make absolutely sure all those FAA-approved wrong answers and Old Wives’ Tales were permanently purged from my gray matter. After all, it would certainly be embarrassing to inadvertently pass any of them on to the next generation of A&P mechanics, wouldn’t it?

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


  1. Hey Mike. Well written. I’ve been teaching A&P and an occasional IA session in my ‘semi retirement’ and after almost 50 years in the flying/mechanicing trades. You hit the nail squarely Sir. Imagine the test prep course I’m going to teach in a couple weeks where I have to explain to a group of folks, paying me real money, that the material I’m fire hosing them with is solely for the benefit of PASSING the FAA written and has little to do with becoming a ‘real’ working mechanic. When I was DOE at a big/old school in New England we had an advisory board made up of reps from industry. They tried to help us shape our students to industry needs. More and more their needs and the exams that had to be passed diverted..badly… We desperately need to get the FAA out of the Bronze age and into SOMETHING more modern than the 727 (Their STANDARD for training),… Of course as an antiquer I feel we do NOT teach enough Dope and fabric or carburetor function… but that’s a whole different subject ripe for a few IA seminars and EAA programs LOL.. Oh well… Render onto Cesar… ooops… that’s 2000 years old too… hmm…

  2. One of the things my instructors told me at Northrup Institute in the late 60’s was to memorize all the material until Friday when the test is given then promptly forget it. The last two weeks of the course was a test every day in each of the various subjects just to refresh our memories so we were ready for the FAA written tests. I can’t say I did as well as Mike but I was right up there. When I took the test there were six sections but you could skip the general section of either the airframe or powerplant tests. The lowest I got was a 79 and the highest was 96. I took the oral and practical at the school from someone I knew so it was fairly easy but still tough enough to test my ability’s at figuring out problems. After a year in GA I went into the navy as an airframe mechanic and in the squadron working on F-8 crusaders they thought I was a god because I knew more about how to fix stuff then anyone else in the squadron.

  3. Even though it is recently overhauled, the Instrument Pilot knowledge test has many of these same problems.

  4. Mike, once again, thank you for an enlightening brief on the subject of governmental bureaucracy I thoroughly enjoyed it.

  5. My son is facing some similar issues at the moment as he works through some advanced ratings. Although it’s a very low probability there is an important risk associated with this problem. Although we all swear up and down that we have purged these wrong answers from our brain the fact that we’ve worked hard to remember them at one time means they are still in there somewhere. Who knows if one day, while distracted or under other pressures, we might accidentally revert to some long buried piece of incorrect information.

  6. I attended the Spartan School of Aeronautic about 1972-74 & 75-76 to return finish up the A&P. I held a Commercial Pilot certificate and also finished up instrument pilot, MEL and all the instructor ratings.
    I had obtained Advanced and Instrument Ground Instructor certificate before I finished my Private Pilot certificate.
    I never used any of the ACME test guides, rather I learned the fundamentals and could answer any question. The FAA began publishing the “official” test guides about 1975-6 as I recall. The FAA did not publish which answer was “correct.” Rather employees of the company, often flight instructors or A&P mechanics took the test and the results averaged to determine which answer was the ACME, Gleim or AOPA answer seemed “most correct.”
    The FAA does change the content of the answers or the order of the ABC .
    The FAA test IS based on WWII-1960 technology because old airplanes still fly.
    Somebody with 20 years as a USAF shop mechanic has zero experience with fabric covered control surfaces and fuselages or wooden propellers and they maybe working for a shop the operates Cubcrafters or Legend aircraft.
    In an ideal world every Sport and Private Pilot would get six months of mechanic classroom and shop experience and every A&P would get a Private pilot certificate. But time and money don’t allow for this.
    AOPA member since 1967

  7. Geez, Mike. After all that, I’d expect you to remove the fact that your were the FAA’s National Aviation Maintenance Technician of the Year from your bio. It’s kind of embarrassing…

  8. Oh, Mike! How well I, too, remember the aggravation of memorizing wrong answers. I went on to teach at several A&P schools where I would teach the material correctly and then teach the FAA answer. Later yet, I was a Designated Mechanics Examiner and had to extract the wrong answer during the Oral part of the exam.

  9. Of all the areas that the FAA is antequated, maintenance training and certification lead the way. I lead Pittsburgh Institute of Aeronautics and we are constantly trying to balance what is required by 40 year old regulations and what has just rolled off the latest assembly line at Gulfstream. Mike, we’d be happy to have you help us and ATEC to pull the FAA into the 21st century with our current lobbying efforts to update requirements. According to employers, PIA always turns out great technicians, in spite of the remedial concepts we are required by regulation to teach.

  10. What a great article. I am 61 and recently retired from a 35 year career in law enforcement and am attending A&P school. I have been at it a year now and am amazed at how many times Ive heard the instructors say “its what the FAA says and we have teach it that way” even though it’s wrong. Amazing to me. When the rookies got out of the police academy their training officer would say ” forget al that crap you learned in the academy,I’ll teach you the real way it is on the streets”I’m not so concerned about guys like me that just want to work on their own airplane and help out fellow pilots. I’m surrounded by old school guys at the airport that can always help me out. I’m concerned about the young people that are trying to make a career and support their families. Would it be best for them to go to work at a shop for three years and take the test after studying ? They would be around real world mechanics and can skip the “theory stuff” in the expensive A&P schools and get down to real world brass tacks. A great article on, in my opinion a very troubling situation the FAA has created. It would be great Mike,if you could write an article advising aspiring mechanics the options for getting their A&P ticket.

  11. Mike, Your excellently written article nails my chief complaint when going through A&P school. You missed the many aerodynamics questions that we had to learn the wrong answers to. I spend 20yrs working as an Electrical Engineer and owning/operating an aircraft on the weekends before I decided to go back to school and get my A&P degree. Now that I’m working in the Aviation industry, I find my feelings about the FAA were cemented during A&P school. They are the biggest obstacles to improving safety, modernization and implementing new technology to our industry. When I installed shoulder belts in my aircraft I found 3 approved STC’s, none of which followed the FAA guidelines for safety restraints. Even though I can get some improvement with a shoulder belt STC, I’m still not allowed to install headrests to help prevent neck and should injuries from a rough landing. Don’t even get me started on why practically every RV out there can run fuel injection on a Lycoming, but we can’t modify our certified aircraft. I’ve never heard of a fuel injection failure in an experimental aircraft, but every year we have crashes due to carb-ice!

  12. While I agree that there are FAA questions in the test bank that are sorely in need of improvement I’m not sure I agree with the examples provided in this article.

    On 8072 there is no correct answer because CHT is a function of heat produced over cooling capacity available, which is unique to every engine/airframe/propeller combination. Typically though, the engine will get the hottest somewhere around stochiometric at higher angles of attack.

    On 8678 the discussion is also not based on physics. The cross sectional area of the mixture control valve on a carburetor is several orders of magnitude larger than that of the idle fuel/air port. One could never reliably lean an engine at idle enough to alter this, without it occasionally dying, the controls are not sensitive enough. Closing the valve to the point where it is smaller than the idle port will likely just shut the engine down. When I bring the mixture back in my MA4-5 (3878) on an O-360 the EGTs rise as it leans, just when the mixture is all the way back. I can occasionally keep it running where there is a slight rise in EGTs. Outside of that it is not running leaner because the smallest orifice in a fluid system determines the rate of flow. Basic physics.

    One 8873, A is more correct than B and C, although the question could be improved in many ways.

    On 8829 the issue is a hot spot, not a hot cylinder, and A clearly says “too much fin area” not one fin. An ailing baffle generally causes the whole cylinder to run hot, or the whole engine due to the overall loss of pressure differential. On the other hand, use the wrong tool on a spark plug thereby damaging the inter-plug span fins and it will get very hot in that one area.

    On 8982 according to the discussion the Cessna manual says it may only be installed in one position, which appears to be answer B, how is this wrong? And this is true of most props. The question wasn’t “can you physically mis-install a propeller with dowel pins?” It is about the rule “if it has dowel pins are you allowed to install it in more than one position?” and the answer is generally “no,” the manufacturers intend it to be indexed only one way. And I’ve seen many A&P installed propellers mis-installed because they didn’t read, or know the answer to this question.

    This all said, don’t get me started on bad FAA questions… the one about the proper way to use a volt meter is utterly ridiculous, every stem is correct.

  13. I also taught at an A&P school, wrote the curriculum etc., and was a DME for many years. What needs to be pointed out here is that these questions are gleaned from the textbooks, and the answers are from those textbooks. The problem as I see it are the textbooks, not the FAA. My guess is that the FAA has nothing to do with writing these questions. (The test writers probably pick out factoids from the books to make into questions.) The newest textbooks are full of errors, and I don’t mean typos!
    Also, regarding the mixture LOP question, the textbook only shows the part of the temp/mixture curve before LOP, so the FAA answer is correct using that data.

  14. Mike,

    Did the practical/oral exam reflect more contemporary issues and best practices, or was the examiner driven by the same painfully antiquated set of testing guidelines?

  15. William Blatter

    October 10, 2015 at 1:41 pm

    Mike, this situation is quite obviously completely unacceptable, and long overdue for correction. What has to be to done to remediate? Please advise.

  16. As of October 2015 the oral and practical testing has changed using the new FAA data base downloader system for induvial oral and practical tests. This is a step in the right direction. In addition, the FAA has put out for review the new part 147 rules for AMT schools and what is taught and
    what needs to be changed. The FAA realizes a lot of advances have changed over the years and again with the new rules this will certainly make things better. I would highly recommend everyone to comment on the new proposed part 147 changes if you want to make it better.

  17. I had a similar experience on the Instrument written. Old systems that don’t even exist today. In the case of Fundamentals of Instruction (FOI) they were just wrong. You could even find in the FAA books that they disagreed with the test. Very frustrating.

    Great article Mike.

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