Real stats on engine failures?

(Rich Stowell) wrote
And I do think it is fair in the case of the stall/spin, for example,
to say that the last maneuver performed by nearly one out of four
pilots who's aviation career has ended in death and who also ended up
in the NTSB database was a stall/spin. This does provide some context
about the stall/spin risk, especially in the accident process leading
to generation of an NTSB report.

Yes, this provides some context. Where I disagree is that it provides
any information as to the relative occurrences of stall/spins vs.
engine failures.

But what about in between the recurrent training cycle? Do you make
any recommendations to your students at all in this regard?

Yes - but they are specific to the individual. It can't be otherwise.
I've done recurrent training for a variety of people ranging from low
time private pilots on end of the scale to an airline captain with 5
digit time on the other.

What to
work on, how to work on it, what frequency to practice? And in terms
of "smoothly with the successful outcome never seriously in doubt" --
do you apply Practical Test Standards to the tasks -- which are
minimum acceptable standards, i.e.: training to the lowest common
denominator -- or do you challenge your students to be better than the
average, the minimum standard?

I apply the minimum standard to decide if the person gets a signature
in his logbook certifying that he has completed a BFR/ICC. Beyond
that, I tailor the training to the individual. The guy with less than
10 hours IMC time is challenged when I give him the hardest task of
the flight - I fail his vacuum gyros and autopilot and he has to hand
fly the GPS approach. The airline captain gets to do a single engine
hand flown ILS to CAT II minima as a warmup. The idea that one size
fits all is ridiculous.

Specific numbers are very much a function of the airplane and pilot
proficiency, and one size does not fit all.

For the majority of GA pilots flying GA airplanes, I have not found
that to be the case at all. The problems I deal with with my students
all fall within a pretty well-defined envelope across the board,
across light, single-engine, GA airplanes. In fact, I would say I've
found it much more difficult for higher time pilots to break their bad
habits simply because the habits have been ingrained for far too long.
The typical profile of the pilot I fly with is a pilot who is active
in general aviation, active in the ratings process, active in the
pursuit of knowledge, experience, safety, and who has 100 to 600 hours
total time.

In other words, you're mostly flying with low time pilots. I suppose
the lower the experience level, the more consistent the performance.
After all, at zero hours most people perform about the same

Seriously, because of the kind of instruction you do, your clientele
is self-selected. I think that tends to homogenize the sample.

In that sense, the pilots I deal with are likely above the average in
terms of their approach to flying and flight safety -- that's why they
are training with me.

One could just as easily say that they lack confidence and feel the
need for additional training in emergency procedures, and maybe the
lack of confidence is justified.

I don't believe a stall-spin involves a typical pilot at all.

The numbers and the anecdotal experience of professional
spin/aerobatic flight instructors are totally at odds with your
belief.

So how many inadvertent stall-spins do they get to see under normal
conditions?

I'm not sure I understand the question...

When doing aerobatic (or emergency maneuvering) training, the
probability of inadvertent stall is high. In fact, I have
inadvertently stalled several times, and once almost spun, but every
one of those instances was while learning or practicing aerobatic
maneuvers. These are not normal conditions, and in any case the risk
is low because everything is done at relatively high altitude, in an
appropriate airplane, with proper training, etc.

I've also seen one inadvertent stall-spin from the back seat of a
glider. The student was a very low time power pilot on his first
glider flight, and he was practicing thermaling flight. That's what I
mean by normal conditions - when a student is doing routine things and
botches them badly enough to stall and spin.

Not true -- I routinely demonstrate one variant of the classic skidded
turn base-to-final

I think skidding the base to final turn AND being slow is pretty
serious mishandling of the airplane. In a glider instructional
situation, it's certain to cause noise from the back seat. Of course
the profile of the average glider instructor is a lot different from
the average power instructor.

And pilots with fewer than either 500 hours total time, or 100
hours in type, are more likely to encounter an inadvertent stall/spin
than to have a genuine engine failure.

Why do you keep going back to the patently unprovable? All we know is
that they are more likely to have an accident caused by stall-spin
rather than engine failure. This tells us nothing about the
likelihood of encountering either hazard.

Thos enumbers are from an NTSB study. I'm notmaking them up. Perhaps
you'd be happier if I prefaced with "Pilots who make it into the NTSB
database share these characteristics..."

No, the proper preface is "Accidents that make it into the NTSB
database share these characteristics." You have absolutely no idea
what sort of hazard encounters these pilots had that did not end in an
accident. The concept I'm going for here is "The rate of accidents is
not an indicator of the rate of hazard encounters."

Now let's consider something else. A pilot who flies 200 hours a year
is 10 times more likely to have an engine failure than one who flies
20 hours a year, since engine failure is not under his control. Are
you seriously suggesting that a pilot who flies 200 hours a year is 10
times more likely to inadvertently spin than one who flies 20 hours a
year? I would argue that he is LESS likely to inadvertently spin,
since the higher level of proficiency that is a nearly inevitable
result of flying a lot and often will make him less likely to miss the
rather obvious clues.

You admitted yourself, all flight time is not equal.

Absolutely. It's simply the only reliable measure we have.

In that regard, I
would say the pilot who flies 200 hours a year of white-knuckled
X-country, averaging one power-on landing every 2 hours, who is
deathly afraid of stalls to begin with and has never spun, and flies
by the adage "maintain lots of extra flying speed just in case" is far
more likely to encounter an inadvertent stall/spin in a stall/spin
critical situation than a pilot who flies 20 hours a year in his
Pitts, 30 minutes at a shot, performing advanced aerobatic maneuvers
and averaging 4 gliding landings per hour (my former Pitts partner did
just this last year). I'd bet on the survival of this Pitts pilot over
the other one in a similar stall/spin critical scenario.

No argument at all. And unfortunately I've met the 200 hours of white
knuckled XC guy. He absolutely refured to turn off the autopilot in
IMC; I could tell he was extremely nervous when I hand flew his plane
for a few minutes. His landings are all power-on. If he encounters a
spin, I doubt he will survive it. But he's not the norm, either.
Typically when a pilot flies 200 hours a year, he's proficient.

Perhaps a better gage of a pilot's ability to deal with stall/spin
critical operations is not flight time, but rather the number of
landings per hour.

I would say landings per year, and rate power-on and power-off
differently. For that matter, different aircraft rate differently.
In a glider, you're never far from a stall. In fact, I have to wonder
if my experience with students is skewed because so many of them are
glider pilots as well... In a Cherokee, you have to work hard to
stall.

After all, one trip around the pattern exercises
many, many critical piloting skills. It would be interesting perhaps
to do a study with this as the hypothesis -- would this interest
you???

Sure. Where would you get the data?

Michael