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75 degree nose-up pitch attitude

Posted: Tue May 22, 2018 7:09 am
by Colonel
Here's one for you, which sounds pretty simple:

Recovery from an unplanned nose-up attitude.  Say 70-80
degrees pitch attitude.

99% of pilots would shove the stick or column forward and
put negative alpha on the wing.  Fluids would float up and
unport, systems would fail, and crud would float up and
jam stuff.  You know, critical flight control hardware.

That's not the correct answer, in case you were wondering.

The correct recovery is a 1/2 roll to inverted, with a gentle
positive alpha to nose below the horizon, then a nice spiralled
co-ordinated 1/2 roll upright, ball in the center.  Positive G
the entire time.

See, the airplane has no eyeballs and does not get scared.
It only cares about the net G acting on it, which I strongly
recommend be gentle and positive, regardless of the pitch
attitude.

Many corner cases in aviation are counter-intuitive.  This is
a meta-lesson which is worthwhile learning, in and of itself.

Re: 75 degree nose-up pitch attitude

Posted: Tue May 22, 2018 9:21 am
by Slick Goodlin
Do you even need to do the full half-roll?  By the time you get a slug like the 172 rolled to 80-90 degrees the nose should be well on its way down.

Re: 75 degree nose-up pitch attitude

Posted: Tue May 22, 2018 4:34 pm
by Chris
I feel like a 172 with that sort of pitch attitude would be more or less ballistic no matter what you wanted to do, unless you intentionally entered with as much speed as the thing would give you.

Re: 75 degree nose-up pitch attitude

Posted: Wed May 23, 2018 11:56 am
by Eric Janson
Unusual attitude recovery in large jets tries to avoid aerobatics - most of us have zero aerobatic experience.

In the case above with no elevator effectiveness the procedure is to roll 90 degrees of bank and let the nose fall below the horizon to get the aircraft accelerating before rolling wings level. Works really well in the Simulator.

Re: 75 degree nose-up pitch attitude

Posted: Wed May 23, 2018 1:54 pm
by Colonel
[quote]roll 90 degrees of bank[/quote]

I guess that's better than putting on the negative alpha.


[quote]most of us have zero aerobatic experience[/quote]

Makes me sad.  There is nothing inherently evil about exceeding
60 degrees of bank or 30 degrees of pitch.  All military pilots
will experience this during their pilot training, and I do not think
that it does them permanent harm.

The airplane has no eyeballs.  The wing and the structure do
not recognize so-called "unusual attitudes".  I might humbly
suggest that the G be kept light and positive.

I find it odd that people who think that they should spend a
lifetime earning $300k/yr tax free, should not have to spend
a day or two learning their craft.  I know, I am an antique
20th century pilot.  I will find a convenient cloud to shout at.

I can teach a nine year old to fly a positive G aileron roll.  Odd
that professional pilots can't step up to that level.

Re: 75 degree nose-up pitch attitude

Posted: Wed May 23, 2018 4:11 pm
by Eric Janson
The aircraft I fly has pitch limits of +30/-10 degrees and roll limits of 67 degrees.

Under normal conditions it is impossible to exceed these values- the aircraft will not let you.

I've never come remotely close to these limits in normal line operations. That would require some major screw ups.

I agree that some aerobatics training would be useful to help in upset recovery.

A number of years ago airbus didn't have stall recovery techniques in the books - their attitude was that you couldn't stall the aircraft. At least 2 crashes have proved them wrong so now the techniques do exist.

The problem is also that the Simulators do not accurately model aircraft behaviour at high altitudes - so a stall in cruise can't be trained. The newest Simulators do have this programmed in but the aircraft I fly are using older Simulators that do not get upgraded.
I certainly wish I earned $300k tax free - I don't know anyone making that kind of money.