An individual human body tests are not 10 ^-9. Not even the old astronaut tests.

But the odds of both pilots failing on the same flight must be better than that. And just because a test failed, doesn't mean there was actually a grounding condition that got missed. Even if you have a grounding condition, and it got missed, doesn't mean you'll stroke out in flight. If you do, the other guy will just land asap. Layered defense.

I can only think of two instances in modern 121 where both pilots were incap. One involved loss of pressurization (not in the US), the other involved guys wearing turbans. Neither were caused by pilot medical issues.

10^-9 is the safety factor for the entire enterprise combined... hardware, software, pilots, ATC, external nav systems, etc.

IIRC that's the allowable threshold for fatal accidents in 121. The UAM folks wanted to use a threshold that was a couple orders of magnitude less.

It would seem that there are some who, lacking any qualification beyond a keyboard at their fingertips, would like to dictate to the FAA and to the aviation medical profession how to do their jobs. A doctor who provides a Class 1 medical is performing a rip-off because it wasn't strenuous enough, wasn't exhaustive enough, wasn't (fill in your favorite bull **** adjective) enough, when those keyboard commandos have neither the authority, nor the training, nor the understanding, nor the liability, nor the legal duty (okay, "liability" is a buzzword for legal duty, but it's more of a mouthful if they're split in two), to sign off a medical certificate. These geniuii (multiple genius's) want do do the AME's job for them, and then the FAAs after that.

The physician, who is acting as an authorized agent of the Administrator in making the medical evaluation of one's fitness, is charged with making the determination. Not joe blow, not al, the wonder-pilot, but Mr. AME. Let them do their job. If the AME feels that the pilot is fit and falls within the guidelines, so be it. The AME isn't certifying one to climb Mt. Everest, or to run a four-minute mile, or even medically qualifying him or her to be the world tostada-eating champion four years in a row. Just to sit in a seat and push or pull a few buttons and survive. That's about it. Can the person do their job as a pilot and be expected to do it within the scope of what's encountered, or anticipated to be encountered, during the course of the job during the course of the medical certificate. Can the AME put his name, and practice and authority on the line by signing that pilot off, and fulfill the scope of his duties representing the FAA Administrator? Then be blessed young jedi, and go forth and jerk the gear and swing the prop or fan. You are authorized. That's it.

Don't make it more-harder than it's gotta be. When we preflight an airplane, we're looking for a reason that it can't go. If we don't find one, then we wave our paws in the sign of the holy fuel truck and the airplane has our blessing. When we inspect an airplane as mechanics, we look for things that ground the airplane, things that are not airworthy, and we make note of them and fix them before the airplane maybe pronounced free of evil and rats, and send it on its merry way. The AME does the same when looking us over, and in absence of one's head sewn to one's kneecap or a heart beat that sounds like a drunken drum solo, or an infected molar leaking out our rectum, then we're released to soar with the eagles and hopefully return to fork over another two hundred bucks to the waiting AME. This doesn't mean the inspection isn't thorough, or adequate, but it's left to the judgement of the guy who went to medical school to make that call, not Pilot Chuck Yeagerite. By convention and by law, that's the way it is, and it doesn't represent corruption, nor a wild-assed guess about the majority of pilots falsifying their data, nor even folks trying or managing to "get away with it." It's a doctor doing his job, a simple exam to determine that the applicant meets the medical standards set forth by the Administrator. That's it.

Don't try to make it more than it is.

If you read carefully I'm not dictating anything, just discussing some additional measures they *could* hypothetically take, and the costs and ramifications of doing that.

People advocating tougher medicals probably don't realize that's most likely going to start with an annual cardio stress test, which is somewhere on the uncomfortable to painful spectrum (if you're not a competitive endurance athlete), and will cost several hundred dollars. Fringe benefit: If you're going to have a cardio event, good chance it will happen on the stress test, so the AME can apply CPR and AED while the ambulance is on the way... as opposed to 2.5 hours out from Midway Island.

We don't seem to have a problem with sudden incap, so I don't see a need to change anything. The current issues in the news appear to be experience related, maybe aggravated by chronic fatigue from high ops tempo?

Exactly. Redundancy. Redundant engines, redundant pumps, redundant instruments. 10^ -5 with two gives 10^ -10, as an example. This assumes independent, unrelated failure root causes.

I wasn't referring to you, or to your comments. Otherwise, I'd have quoted you.

Well, yes and no. That safety factor (or as they say, extremely improbable) is used for failures where the result is catastrophic. Pilot incapacity in a two-pilot plane is not a catastrophic event, and thus does not need to be certified to that standard.

Total aside. Human interest.

The Six Sigma Handbook (Quality) was edited by Forest W. Breyfogle III. Why has he been interested in Quality?

https://en.wikipedia.org/wiki/1956_G...-air_collision

The TWA Flight Engineer in the crash was his father, Forest W. Breyfogle Jr.

What started as the tragic death of his father, grew into a passion of preventing airplane accidents, and quality in general.

“Brey”, his father and the entire family, were active members of the church I grew up in.

All redundant systems, taken together, get factored into the total. I imagine that would include pilots, have no idea how they calculate it.

General population health stats?

Stats on inflight pilot incap?

Actually I don't think I've ever heard of a dual pilot medical incap in an airliner, ever. Maybe they just assume that since it's never happened, the odds are low enough to be well below the certification threshold so as to be statistically insignificant. Ignore it in other words.

Although they have to use some kind of math when they make changes to pilot medical certification policy. If nothing else to justify on paper whatever wild idea they pulled out of their butt.

Many years ago - back even before my time - a Wing Commander at an overseas USAF base landed his F-4 and had a heart attack on the roll out. The WSO called a medical emergency when his front seater became unresponsive and got the aircraft taxied to the arm/dearm area where the fire/rescue/medical people extracted the pilot who couldn’t be successfully resuscitated. This occurred only two weeks after the man’s annual flight physical - which HAD included an ECG which - even in retrospect - had been totally normal.

Against the recommendations of some of the medical personnel and all of the statisticians a policy was implemented for all fighter pilots that an Exercise Treadmill Test be included in the annual flight physical for all currently flying fighter pilots and that all personnel showing an “abnormal” exercise treadmill test be referred to the aeromedical consult service, the USAFs central point for difficult problem cases. There those people would be further evaluated.

Those opposing the new policy cited as their reason something called Bayes Theorem or the Law of conditional probability. Not to get too didactic, what this means is that any medical test has a certain percentage of false positives and a certain number of false negatives and there generally isn’t an actual “normal” or “abnormal” except as defined by the desired sensitivity and specificity of the test. Generally speaking if you tweak the sensitivity up you get more false positives while if you tweak the sensitivity down you get fewer false negatives. And with specificity, it’s just the opposite. If you tweak the specificity up you get fewer false positives at the cost of more false negatives. But what really drives the predictive value is the actual frequency of the disease/illness /condition in the population being tested.

If I recall correctly (from a paper I wrote for squadron officer school years ago) the policy lasted about a year and a half and generated just over 200 referrals for further evaluations. All personnel over 35 (a minority in the actively flying fighter pilot community) needed to agree to a cardiac catheterization before they could be returned to flight status.

The program was abandoned after about 18 months and they reverted to the old rules because all but one of the “positive” treadmills in the group turned out to be false positives and that one true positive also had an abnormal resting ECG and would have been picked up under the previous criteria in any event. IIRC, some small number (a half dozen or so) fighter pilots were lost from flying because they refused the cardiac catheterization (which back in that era carried somewhere between a quarter and a half percent MORTALITY). I believe they were all allowed to go to two pilot cockpits though in tankers, transports, and bombers. Whether any ever got back into TACAIR I was never able to discover.

But anyone recommending tightening of medical standards really does need to understand Baye’s Theorem. Doing the “right” thing is not intuitive.

https://youtu.be/HaYbxQC61pw?si=QeQDCZbVeBL6Cz-9