Frank van der Hulst wrote:

On Tue, 16 Feb 1999, Paul wrote:

If you fly a V-tail Bonanza 15 degrees nose-down for 26 seconds, how much
height do you lose?

About 2600 feet. Not all aircraft have been lost on approach.
Some have broken up in the cruise mode. Some have flown into the ground.

15 degrees seems a lot of pitch to not notice whilst looking at maps or
approach plates.

It's not a lot on the attitude indicator.

100fps = 6000fpm -- that's a lot on the VSI.

IMC so you won't see anything if you look out. Most of these accidents
happen at night as well.

Or look at the altimeter in IMC... Keerist, my instructor expected me to
keep within 100ft of my desired altitude flying VFR. I'm sure that ATC
would take an *extremely* dim view of someone departing their assigned
altitude by over 2000ft.

I'd suggest that to be unknowingly 2,600ft below your desired altitude
(whether in IMC or not) and/or 200kts overspeed *is* pilot error.

IIRC, you're supposed to scan the instruments every 5 seconds or so? I'm
not intrument-rated, but did 5 hours under the hood a couple of years ago.

Frank.

130 kts overspeed not 200 Kts. Cruise speed is stated at 160 Kts.

One thing I forgot to mention Frank is the peak overspeed results
in flutter. No gust is necessary. The airplane breaks up.
In 26 seconds you are dead.

It sometimes takes 20 seconds or so and I am guessing here 
for the radar beam to come around and recieve the altitude 
encoding transponders signal. In that length of time the airplane 
can disappear from the radar screen. According to Dr. Roberts 
the typical accident happens in 10 to 20 seconds. 

There are many things that can distract you 
while flying IFR. Just digging through your flight bag looking
for your approach plates or flashlight. A minor or major problem with
the engine gauges, passenger problems.etc., etc., etc..

Dr. Roberts did not mention this but a constant speed prop will
keep the engine RPM constant by increasing the pitch on the blades
as the aircraft decends. No clue there.

Yes the pilot error perception problem is a big issue. 

I think what Dr. Roberts is saying; with minor structural changes 
the high performance  airplane can be more forgiving. He states a 
that a ten percent increase in stiffness produces a 50% decrease 
in airframe failure.

He has a little chart of Probability of Failure.
GA....................... .041
Transport................ .0046
10% increase in strength  .034
10% increase in stiffness .021

As it is now GA airplanes are designed to strength criteria.

Again I suggest you get the paper. I may have some facts wrong
as it was a heavy duty presentation rather poorly done.
It needs the help of a good technical writer working with
Dr. Roberts. Like many brilliant men he assumes the audience
is smarter or more educated than they are. 

PL

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