You could see opposite aileron being applied to correct the wing drop as well - they didn't recognize the stall maybe. Ouch.
 
<<Note: This is a discussion for lessons-learned sake, not conjecture into probable cause.>>

As an aviation safety investigator, this video leaves me asking plenty of questions that won't get answered here. Are those the right flaps for this phase of flight (takeoff or go-around)? Is the engine producing full power if it was commanded? Why was he turning rather than proceed straight ahead if the pilot was approaching a stall? And did he know he was nearing a stall?

I agree completely: An AOA system is hugely valuable for avoiding events like this, but please get smart understanding what the instrument is actually telling you and what to do about it. Stall AOA can differ for different aircraft configs (ie, flaps up or down) and bank angles. Fly safe! :cool:
 
scrollF4 said:
<<Note: This is a discussion for lessons-learned sake, not conjecture into probable cause.>>

As an aviation safety investigator, this video leaves me asking plenty of questions that won't get answered here. Are those the right flaps for this phase of flight (takeoff or go-around)? Is the engine producing full power if it was commanded? Why was he turning rather than proceed straight ahead if the pilot was approaching a stall? And did he know he was nearing a stall?

I agree completely: An AOA system is hugely valuable for avoiding events like this, but please get smart understanding what the instrument is actually telling you and what to do about it. Stall AOA can differ for different aircraft configs (ie, flaps up or down) and bank angles. Fly safe! :cool:
Click to expand...

Stall AOA should not change based on bank angle. It will change based on flaps but the good systems use flap position to give correct info.
 
sailvi767 said:
Stall AOA should not change based on bank angle. It will change based on flaps but the good systems use flap position to give correct info.
Click to expand...

Right on - that's exactly why it's so useful.

I found through testing that the AoA warning isn't significantly impacted by flaps - with the AoA calibrated to a clean wing, the stall breaks exactly when the last red chevron on the AoA indicator disappears. With full flaps, the stall breaks when the second-to-last red chevron disappears. Given that there are three red chevrons, a couple of yellow ones, a couple of yellow bars, and a bunch of green ones, this seems ok to me.

It also starts aural annunciation long before critical AoA is reached.
 
Regarding bank angle: you are correct that bank angle itself doesn't effect stall AOA. However, it does effect what the pilot is trying to accomplish. In this case, if he's trying to climb, he must increase pitch to climb through the turn. That increases AOA (which may not be in his crosscheck).

Regarding flaps: on many aircraft, flaps and slats changes indicated stall AOA. Secondary flight controls change the wing's camber and realign the chord line's orientation to the relative wind. The stall AOA itself may be consistent, but how that is indicated may change from the chord line realignment. Not necessarily on all designs, and apparently not on our RVs, but it may. Deploying flaps/slats on an F-4E dropped the indicated stall AOA by several units on the gauge.
 
scrollF4 said:
Regarding bank angle: you are correct that bank angle itself doesn't effect stall AOA. However, it does effect what the pilot is trying to accomplish. In this case, if he's trying to climb, he must increase pitch to climb through the turn. That increases AOA (which may not be in his crosscheck).
Click to expand...

...or pulling through the buffet over the top trying to gain angles so that ...erm... never mind ;)
 
scrollF4 said:
Regarding bank angle: you are correct that bank angle itself doesn't effect stall AOA. However, it does effect what the pilot is trying to accomplish. In this case, if he's trying to climb, he must increase pitch to climb through the turn. That increases AOA (which may not be in his crosscheck).

Regarding flaps: on many aircraft, flaps and slats changes indicated stall AOA. Secondary flight controls change the wing's camber and realign the chord line's orientation to the relative wind. The stall AOA itself may be consistent, but how that is indicated may change from the chord line realignment. Not necessarily on all designs, and apparently not on our RVs, but it may. Deploying flaps/slats on an F-4E dropped the indicated stall AOA by several units on the gauge.
Click to expand...

Flaps do make a change on RV's. Trailing edge flaps in general actually decrease the stall AOA. They increase the coefficient of lift at a given speed however and that is usually considered worth the trade. Leading edge slats on the other hand increase the stalling AOA but do little for lift. The combination of trailing and leading edge devices work well together for that reason.
Unlike the F4 AOA guage the systems in most RV's are calibrated in a flaps up and down mode and will give the correct stalling AOA regardless of flap position if you have a flap position input to the AOA system. If not the difference as mentioned is not great.

George
 
Education

As much as I love AOA's and find them useful, I'd love to see people spend as much money as they do on advanced avionics on their own education and good flight instruction! :-(
 
PabloJ3 said:
As much as I love AOA's and find them useful, I'd love to see people spend as much money as they do on advanced avionics on their own education and good flight instruction! :-(
Click to expand...

Yes, and lots of practice with MCA/slow flight at altitude, and vigilance in not letting your IAS drop too low in the pattern.
 
PabloJ3 said:
As much as I love AOA's and find them useful, I'd love to see people spend as much money as they do on advanced avionics on their own education and good flight instruction! :-(
Click to expand...

Yes, and the pilots should demand that instructors be tough. I told my instrument instructors that their job was to teach me, then load me up to see what my limits are, while it is safe. They did just that, it resulted in discipline and personal procedures that were designed to keep me out of trouble. One guy had an extendable metal pointer - he did not talk, just tapped the instrument and tapped my hand if it was not doing the right thing (like holding the pencil when it should have been returned to the clip). I had several very good teachers and each one made me better in different ways.

That was 3 decades ago and I probably will never get that competent again, but WILL try.
 
There is no substitute for good instruction and sound flying skills. That does not mean however something as valuable as AOA with a audio warning should be skipped. The systems today are to good and the cost is to low to miss a critical safety enhancement like this. Some of the very best pilots I know have made tragic mistakes.

George
 
OK

A learning point here, not criticism - summary - my instructors drove home the point that generally speaking below a certain speed as you enter 'slow flight', ailerons aren't very effective in raising the low wing - in fact they may cause the 'low wing' to drop further due to the drag produced by lowering the aileron on the low wing.

We all learned to use only the rudder not ailerons at slow flight. It is somewhat counter intuitive to use only the rudder, not the ailerons when in slow flight.

So we need to practice, practice, practice slow flight. Enough said.
 
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