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AoA Indicator

Posted: Thu Jun 28, 2018 3:03 pm
by Colonel
I tell people, that the stick/column is a pretty good proxy
for an AOA indicator.  If it's all the way back, you're probably
at a pretty high AOA, regardless of your airspeed.

The pilots of Colgan 3407 and AF 447 were unaware of this
little tidbit of information.  They hauled all the way back and
to their great surprise, they were at a very high AOA, so they
kept it there.  For 3.5 minutes, for AF447.  I can't hold my
breath that long.

Bonus points for the snap rolls for the four bar of Colgan 3407.

Here's a fun trick:  set the pitch trim neutral in straight and
level flight.  Now, try to stall the aircraft without touching the
stick/column.  It's not easy. 

To do so, you will have to haul it all the way back. 

There's your AOA indicator.

Let go of the stick, dummy.  The aircraft will fly much better
without you screwing it up.  This is in fact the essence of spin
training and recovery.

I only instructed continuously for 22% of the history of powered 
human flight on anything with wings, so I probably don't know
shit, though.  [b]BAD PERSON[/b].

Re: AoA Indicator

Posted: Thu Jun 28, 2018 3:12 pm
by mcrit
[quote author=Colonel Sanders link=topic=8651.msg23762#msg23762 date=1530198231]

Here's a fun trick:  set the pitch trim neutral in straight and
level flight.  Now, try to stall the aircraft without touching the
stick/column.  It's not easy. 

[/quote]

By 'not easy' do you mean 'not possible' ? :)

Re: AoA Indicator

Posted: Thu Jun 28, 2018 8:12 pm
by cgzro
That's covered very nicely in Stick and Rudder. Everybody should read it once every few years.

Re: AoA Indicator

Posted: Fri Jun 29, 2018 4:09 am
by Colonel
Keeping in mind that revisionism can be nauseating ...

Langewiesche did a marvellous job in 1944, but IIRC
he had some pretty strange stuff in there, too.  A real
mixture there of diamonds and carbon, and perhaps a
buckyball or two.

Re: AoA Indicator

Posted: Sat Jun 30, 2018 11:55 am
by Fendermandan
Attitude + power and develop the feel for the plane and it will be all good.
I never flew something big like 777 but people that do, say that this method works on them too.

Re: AoA Indicator

Posted: Sun Jul 01, 2018 3:52 am
by Colonel
[quote]Attitude + power[/quote]

Exactly.  It's a very 20th century concept, but works well
regardless.

Two exercises I used to like to do with students:


1) In the 172 (steam gauges) bring a couple of 8.5x11 blank
pieces of paper, and use them to cover up the entire panel on
the left (student's) side, pushing holes through the knobs to
hold the paper in place.

Then, have the student start, taxi, take off, climb and navigate
to the practice area, do some slow flight, head back to the airport,
join the downwind and land ....

With no gauges whatsoever.  Ok, maybe oil pressure and a tach
but that's all.  No flight instruments.

Students were really nervous at first, but without exception it was
exhilarating for each and every student I did this with, when they
realized that all that shit in the dash was optional.

Look outside.  Use the Real Horizon.  Attitude + power = performance.


2) In aircraft with glass panels, pull breakers.  I was checking out a
new co-owner of a homebuilt with no steam gauges, just a couple of
displays with black trim.  New co-owner told me he thought he was
dead if they failed.  I laughed, and before start, popped the breaker
so he had no flight instruments.  Blank display.  Amazingly the aircraft
flew perfectly.  He couldn't believe it was possible to fly (and land) an
aircraft without flight instruments.


This shit makes me cry.  Doesn't matter I guess, I quit instructing in
2015.  No place for 20th century pilots in the 21st century, where
everyone flies plastic airplanes with nosewheels and yards of colored
glass in the panel and no one looks outside and everyone is shocked
when they have a mid-air.

[img width=500 height=375]https://cdn.dribbble.com/users/110294/s ... im_gif.gif[/img]

Re: AoA Indicator

Posted: Sun Jul 01, 2018 10:03 am
by Eric Janson
[quote author=Fendermandan link=topic=8651.msg23778#msg23778 date=1530359740]
Attitude + power and develop the feel for the plane and it will be all good.
I never flew something big like 777 but people that do, say that this method works on them too.
[/quote]
The basics of flight remain the same no matter how big or complex the aircraft is.
Have a look at a PFD (Primary Flight Display) - it mirrors the 'Basic T' instrument layout.
As part of  Line Training I cover the Pitch/Power combination to maintain level flight in cruise. For the A340 this is 2.5 degrees of pitch and 88% N1. If you set this it will keep the aircraft flying safely while you figure out what is going on.

Good practice to know these settings for whatever you're flying.

Re: AoA Indicator

Posted: Sun Jul 01, 2018 2:26 pm
by Colonel
[quote]in cruise[/quote]

The idea of someone losing airspeed control in coffin corner is a frightening one:

[img width=500 height=427]http://www.boldmethod.com/images/learn- ... corner.jpg[/img]

Mind you, Boeing does build a good airplane:

[url=https://en.wikipedia.org/wiki/China_Airlines_Flight_006]https://en.wikipedia.org/wiki/China_Airlines_Flight_006[/url]

[quote]Without any visual references (due to the clouds) and having rejected the information from the ADIs, the captain and first officer became spatially disoriented.

Only after breaking through the bottom of the clouds at 11,000 feet was the captain able to orient himself and bring the plane under control.

They had descended 30,000 ft in under two and a half minutes while all onboard experienced g-forces, as high as [size=18pt][b]5[/b][/size]g.

Captain had approximately [b]15,500[/b] flight hours.
The First Officer had more than [b]7,700[/b] hours, and
the Flight Engineer had approximately [b]15,500[/b] hours of flight time.
The accident occurred while the main crew was on duty[/quote]

'Way overspeed [i]and[/i] overG - at the same time!  Kudos to
the flight crew with almost [b]40,000 hours[/b] of combined flight time.

[img width=500 height=312][/img]

Re: AoA Indicator

Posted: Sun Jul 01, 2018 8:06 pm
by John Swallow

The FAA and others are big on angle-of-attack indicators and are making it much more simple to get them installed on small GA aircraft. 


I remain skeptical of their benefit for that segment of the flying fraternity.


The stall speed range in my aircraft varies 7 knots from AUG to minimum fuel/one pilot.  If I wished, I could vary my approach speed by that much.  However, the only speed I aim to nail is the "power off/in the flare/across the button" speed.  And,  according to the literature accompanying most AOA gadgets,  by then, I'm not watching the indicator any more.  The take away:  of limited use on approach; little use during the flare.


BUT, THE US NAVY USES IT ALL THE TIME! is the cry.


Yes, they do.  When you're landing on a moving postage stamp, you want to have your approach speed right on the money.  All the way to touch down.  No finesse; no fancy flare. Just a bungee stretching smack down on the deck at around 700 feet per minute.  So, pegging the glide slope and the AOA is important.  But, no flare.


The proponents of the AOA are convinced that it will reduce or eliminate "loss of control" caused by inadvertent stalls during manoeuvring flight in the circuit or during silly ass low level aerobatics and the like.


If the inclusion of an AOA system saves one life, that would be good; however, I'm of the opinion that during these types of manoeuvres, the only thing that will stop a pilot from continuing into the jaws of death at that point is something that will give him/her a sharp boot in the nether regions accompanied by a loud "Arsehole!" in the headphones.  Because by that point, one's attention is not on the indicator sitting high in the yellow band or buried in the red; no, the attention is fixed on his folks farmhouse or his adoring friends in the field below. 


There is one AOA system that does give auditory notice:  it starts off as a slow "beep.........beep.........beep..........beep and increases as the speed reduces and/or AOA goes up:  "Beep......beep....beep...beep..beep.beep.beep.beepbeepbeepbeepbeep. 


It would be annoying as hell on every approach leading one to disregard it. 


I and my confrères flew all sorts of low, medium, and high-performance jets without the benefit of any on-board AOA indicators.  (Save for the pilot, of course)  Very few aircraft were lost to the classic stall/spin scenario.  (We did lose  '104s due to pitch-up: to prevent exceeding the critical angle of attach,  these aircraft were fitted with stick shaker and stick pusher.  However, a determined pilot could easily outwit these two bothersome measures..).


For the majority of light GA aircraft, the ASI is a good an AOA indicator as there is. 


What is NOT needed is more gadgetry.


What IS needed is more flying.  More hours. More practice.


I can get by with flying about 120 hours a year - VFR only plus some aerobatics.  That's because I've got years of experience on which to draw.  We've got people here who only fly about once a week.  Some folks less. 

Their flying skills and radio work reflect their lack of practice. 


AOA indicators are not going to help these people...












Re: AoA Indicator

Posted: Mon Jul 02, 2018 1:48 pm
by Colonel
[quote]What IS needed is more flying.  More hours. More practice[/quote]

Exactly!  I tell ANY pilot with less than 1000TT - try to fly twice a day.


[quote]I can get by with flying about 120 hours a year[/quote]

Heh.  I bet a lot of people [i]wish[/i] they could fly 120 hours/yr.

But it's not just about the hours.  It's about [i]how[/i] you fly the
hours.  That sounds strange, but hang on.

Decades ago, I flew 105 hours in twins in 21 days.  Averaged
5 hours a day in those pigs.  At the end of it, I was very comfortable
in that type.  I am certain that if I spent 105 hours over say FIVE
YEARS doing the same thing, I would not have attained the same
skill level.  But my logbook totals - which is the only metric people
look at - would be the same.

Decades ago, I was fascinated to learn how the Soviets won the
Unlimited Aerobatic WAC yearly contest quite consistently.  Their
pilots - the best in the world, year after year - [b]flew 40 hours a year.[/b]

No typo.  The best pilots in the world flew 40 hours per year.  Because
they flew 120 training flights, 20 minutes each, doing surface acro
right overhead the airport, with a coach watching every move that
was carefully critiqued afterwards.

So many lessons there.  Intensity of training.  Careful observation.
Intense post-flight de-briefing to correct errors.

All terribly important and almost completely absent from civilian
flight training, which is why people will spend 100 or even 200
hours getting a bare PPL these days.

When I instructed, the training was very concentrated and I am
sure of the students felt overwhelmed.  The trick is to figure out
what workload - everyone is different - will result in their brain
running at 100% capacity.  Then, after the flight I ask the student
to write down what we did during the flight.  How to do it, and
what errors they made, and how to avoid them next time.

Then they emailed it to me, I reviewed it, corrected it, and sent
it back to them for further review.

Using this technique, I was able to send a young fellow solo in
his S-1 Pitts in five hours, for example.


[img width=500 height=267][/img]

Civilian flight training is such a train wreck.  Even the tiniest
improvement in instructional technique yields an incredible
improvement, compared to the median.

Disclaimer:  I only instructed continuously for 22% of the
history of powered human flight, so WTF would I know?