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-   -   Safety through AOA (https://www.airlinepilotforums.com/safety/76236-safety-through-aoa.html)

USMCFLYR 07-30-2013 04:04 AM

Safety through AOA
 
The forum has had recent discussions on the use of AoA - particularly on the value added to GA. This FAASafety brief came through the email this morning.


FAA Safety Team | Safer Skies Through Education
What’s your angle?
Notice Number: NOTC4886
Want to help reduce GA accidents? Know your angle. Angle of attack, that is…

The majority of GA accidents occur when a pilot loses control of the aircraft. This usually happens in airplanes when a wing stalls and the plane enters a spin. The wing stalls when the critical angle of attack (AOA) is exceeded.

Remember, the wing (and aircraft) can stall at:
· Any airspeed
· Any attitude
· Any power setting
But, the wing always stalls at the same AOA.

The stall speed published in the airplane flight manual is only valid for:
· Unaccelerated flight (1g load factor)
· Coordinated flight (ball centered)
· At (usually) max gross weight
So, a pilot may be surprised to find the wing has stalled above the published stall speed.

AOA can be very useful in enhancing safety. Having an AOA meter is the best way to remain aware of your AOA.



If you don’t have an AOA meter, here’s a quick tip on how to manage your critical AOA:
  • See it – in the pitch attitude and airspeed indication.
  • Hear it - in the existing stall warning systems.
  • Feel it – in the seat of your pants when the wing begins to buffet.
  • Recover it – by reducing the pitch of the aircraft.
Regardless of the aircraft’s attitude, reducing the pitch reduces the angle of attack and recovers from the stall.


Want to learn more?


Timbo 07-30-2013 04:36 AM

If you want to learn more about AOA and spins, in addition to picking up one of those books above, go out and find a good acro instructor and go flying. Books are great but there's no substitute for experience in an airplane, that's where you will develop the 'feel' for what the airplane is telling you.

Start looking for good Acro IP's, and read some good stuff, free right here:

http://eaa.org/intheloop/issues/default.asp

Hey, with enough practice, you could even land upside down, like this:

http://www.youtube.com/watch?v=1ApSDpnA2k0

Bilsch 07-30-2013 01:01 PM

Thanks for the links USMCFLYER. FAASafety Team puts out some good stuff.

galaxy flyer 07-30-2013 01:56 PM

USMCFLYR

It would nice if the FAA Safety guys went down the hall or across the country and met with the Aircraft Certification guys. AoA is not recognized as a legal "tool" for performance. Current Bombardier planes now have AOA indications on the panel and, where installed, in the HUD, but, because it can't be used legally, the AFM contains not data, there are no markings or data for different performance points--like on-speed for Vref, V2, etc. The C-5 manual had specific numbers-7.2 units for approach, 9 units for V2.

GF

USMCFLYR 07-30-2013 02:01 PM


Originally Posted by galaxy flyer (Post 1454333)
USMCFLYR

It would nice if the FAA Safety guys went down the hall or across the country and met with the Aircraft Certification guys. AoA is not recognized as a legal "tool" for performance. Current Bombardier planes now have AOA indications on the panel and, where installed, in the HUD, but, because it can't be used legally, the AFM contains not data, there are no markings or data for different performance points--like on-speed for Vref, V2, etc. The C-5 manual had specific numbers-7.2 units for approach, 9 units for V2.

GF

As I am learning in my job, stovepipe is still a term in use in the FAA :(
Yes - It would be nice to merge the two and actually get something useful (and safe) out to the GA world quickly.
I agree about the military's use of AoA in operations (and I didn't even know that other communities outside of the Strike/Fighter one used AoA as much), but we had AoAs for nearly everything - especially tactically, but including max range, max endurance, and of course LANDING!! :D:eek:

Bilsch 07-30-2013 03:55 PM


Originally Posted by USMCFLYR (Post 1454337)
As I am learning in my job, stovepipe is still a term in use in the FAA :(

It is something that is changing slowly. Old habits (and protective custody of one's territory) die hard. :D

galaxy flyer 07-30-2013 04:49 PM

USMCFLYR

The numbers were published for the C-5, but it wasn't trained firmly. I learned to use it as an IP from old IPs who were saved by watching it. Especially good on 3-engine missed approaches, if the student got overly aggressive and as a clue on configuring.

There are absolutely no numbers published for Bombardier planes, we were told to get back to the engineers with our observations on the AOA presentation. OTOH, the Citations, from Day One, had the standard military chevron and donut display in the glare shield.

GF

cardiomd 07-30-2013 04:54 PM


Originally Posted by USMCFLYR (Post 1454337)
As I am learning in my job, stovepipe is still a term in use in the FAA :(
Yes - It would be nice to merge the two and actually get something useful (and safe) out to the GA world quickly.
I agree about the military's use of AoA in operations (and I didn't even know that other communities outside of the Strike/Fighter one used AoA as much), but we had AoAs for nearly everything - especially tactically, but including max range, max endurance, and of course LANDING!! :D:eek:

In military though accelerated stalls are much more common, so AOA would be critical, while even utility category craft do not as often pull G's / bank so the airspeed is a much more useful surrogate of stall... I remember in training a demonstration of "accelerated stall" in a 172 and it was very underwhelming. At high G capable aircraft I'm guessing it is very impressive...

USMCFLYR 07-30-2013 05:05 PM


Originally Posted by galaxy flyer (Post 1454457)
USMCFLYR

The numbers were published for the C-5, but it wasn't trained firmly. I learned to use it as an IP from old IPs who were saved by watching it. Especially good on 3-engine missed approaches, if the student got overly aggressive and as a clue on configuring.

There are absolutely no numbers published for Bombardier planes, we were told to get back to the engineers with our observations on the AOA presentation. OTOH, the Citations, from Day One, had the standard military chevron and donut display in the glare shield.

GF

CLASSIC! :D

I wonder though if they used 'green' for slow and 'red' for fast as Naval Aviation does or if the civilian world considers 'red' as near stall. Looking at the other video posted of the amphib, that display used red as the dangerously slow region color of warning.

galaxy flyer 07-30-2013 05:07 PM

I don't have any Citation books, it's been 30 years since I flew it, but I think it was AF presentations--red = slow, green = good. And I could be wrong there, too. It's been almost 30 Yeats since I bailed out, literally and figuratively, from the A-10, the last AF plane I flew having that display.

The AOA presentation is so small on the Global screens, you really have to look for it. I flew with an ex-French Navy pilot recently and we both missed it.

GF


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