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A Syllogism

The Piper Warrior with a taper wing has had no (few) fatal accidents due to stall/spin, despite stall/spin accidents being a major source of fatalities in GA. (around 25-30%?)

There has been few (no?) VMC to IMC fatality by pilots with an IMC rating, despite VMC to IMC being a major source of fatalities in GA (30%?).

Therefore if we only flew Warriors and held IMC/IR(R) ratings the GA accident rate might be reduced by more than 50%.

Enstone (EGTN), Oxford (EGTK)

Yes, nice try to Bayes stats ;)

You need to know more to infer anything,
X = Proportion of Warrior pilots in those who hold IMC (probably higher than % of Warrior pilots in large population)
Y = Proportion of Stall/Spin accidents in VFR/IMC accidents (I guess zero as investigator partition the two sets?)

Let’s assume Y is zero, if X is zero then you will not reduce anything, if X = 100% then you get 20% reduction in accident rates

EGSX, United Kingdom

I would also suggest that an estimated 75.8% of the PA28-140 fleet flies between Blackbushe and Sandown, on Sundays, with the free landings tokens from some magazine, with cloudbases above 3000ft and visibility above 10km, winds below 5kt, and on that sort of mission profile the principal hazard will be in-flight cardiac-related pilot incapacitation resulting from this eaten at Sandown

Shoreham EGKA, United Kingdom

Peter wrote:

on that sort of mission profile the principal hazard will be in-flight cardiac-related pilot incapacitation resulting from this eaten at Sandown

That is what I meant by X = 0%,
If having IMC & flying an Warrior are independent then you can get 6% accident rate reduction from the intersection (30%*20%)

On food habits, you can get spin/stall from WnB but they will typically be in the take-off/landing cases rather than vfr/imc (unless you had an afternoon nap after that lunch while TS build up )

EGSX, United Kingdom

I’ve never spun the Warrior (=not allowed) but no amount of stall practice has ever suggested any kind of wing drop.

IMC is another matter since the proportion of IMC’s even in Warriors is so small and smaller still would be the proportion of IMC pilots with current instrument practice, which I would suggest is somewhere between vanishing and infinitesimal.

Maybe a bigger contributor to the no spins in Warriors (if this is indeed true) could be the fact that the Warrior pilot limits rudder use to steering on the ground…

EGBW / KPRC, United Kingdom

The NTSB have a lot of fatals in IMC with IR pilots. Usually a few every month.
I prefer the Pa28 to the C172 but cannot think of any reason one would have more accidents than the other.

EGPE, United Kingdom

Maoraigh wrote:

lot of fatals in IMC with IR pilots

Those don’t mix that well neither, the real question is the proportion of IMC hours vs IFR hours for a typical IR pilot?
My guess is that for CAT IR rated pilots that would be 5% of IFR time in IMC? not sure about GA IR rated pilots but that could probably be higher somewhere around 10%?

Also, it will be also interesting partition is how much of that was in solid IMC vs marginal VMC? A large number of IR pilots got killed by attempting to fly bellow a low ceiling in low visibility rather than “staying safe” in solid IMC (you can call this “IMC into VMC”)

Here is a nice paradox: in low visibility one will find the runway much easier with 200ft minima/ceiling than 1000ft minima/ceiling, you have more chances of getting killed in the latter if you don’t let it go, in/out of cloud is a binary choice while forward visibility is a highly relative concept

Last Edited by Ibra at 11 Feb 20:47
EGSX, United Kingdom

The IMC claim is local to the UK, and was used to defend the IMC rating.

Statistically the Warrior/172/DA40 have enjoyed a safety record around 2x better than private GA, not sure what this does for a Bayesian analysis – although accidents tend to be poissonic, with a thicker tail than the normal Gaussian curve.

Enstone (EGTN), Oxford (EGTK)

It is an excellent UK rating and give the same utility as full IR for IMC flying (both subject to currency, I know some who probably never flew GA in cloud, do get hurt by this statement) but does not allow full IFR capability (this brings some dangers !), my guess the reason of its sucess is probably the perfect match with UK GA fleet (pipers, cessnas, dimonds) and aerodromes capabilities?

Personally, the way I view IMC rating (or even full IR) for GA use: they give you say 30min in IMC before you crash or you find a safe way out, some will call that “out of jail” or “get in jail”, but in any case 30min it is far better than 180 seconds and more than enough for a pilot who did a good planning but still getting some unexpected glitches

Higher than 30min in weather and one needs to start investing heavily in his training, aircraft, systems and even hire pilots…

Why 30min? One has to set some random limit and live with it, mine is probably less than that

This has been debated to death in FAA world, especially that reduction of 200h to get an IR !

Last Edited by Ibra at 11 Feb 22:24
EGSX, United Kingdom

“Personally, the way I view IMC rating (or even full IR) for GA use: they give you say 30min in IMC before you crash or you find a safe way out, "
I did get an IMC rating, but let it lapse. I was not going to stay current. Also the aircraft I’d bought a share in had poor gyro instruments.
But I question the 180 seconds. I was revalidating my IMC with instructors who stressed the likelihood of losing control if I flew in cloud, when I stopped.
The ex-WW2 reconnaissance Spitfire pilot who taught me when I regained my licence failed to teach me this in the few hours under the hood, and I did get into cloud several times in my first year renting his C152. Each time I did a 180, and came out, in control, at least once well after the three minutes were up.

EGPE, United Kingdom
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