PPRuNe Forums - View Single Post - AF 447 Thread No. 7
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Old 31st March 2012 | 18:16
  #1138 (permalink)  
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Joined: Jun 2009
: Military
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From: florida
Back to AoA one mo' time

Salute!

@ Doze:

Redundancy is required, no problem with that. OTOH, graceful degradation is also required. So why throw out the one sensor that actually indicates the ability of the wing to provide lift or lack thereof? By the time the AoA sensors are invalid I can guarantee that the plane's wings aren't providing useable lift doofers.

'bird has it right. Start off using the AoA for approaches, as it inherently compensates for weight and such to provide the best aid in the cockpit.

Being a USAF jock, we used a baseline speed and added knots for fuel weight and such. The U.S. Nasal Radiators used the AoA indexer lights and such. So I was impressed once flying the A-7D, which was a Navy design which the USAF adopted and improved. Gotta tellya that an approach was much safer and easier than what I had been used to.

Sure, a good crew will compare the speed based upon weight with the AoA, but once close, AoA was the primary aid for an approach.

Once gear up, our Viper AoA "bracket" went away. Due to our operational requirements and design of the FBW system, pulling full back gave you the best AoA for the gee you were commanding. By the time you reached the max AoA you were in one Gee flight ( we hit 9 gees at 15 degrees).

For the 'bus, I can see an AoA indication in cruise configuration that is small and basically unimportant. But when the system starts to revert to backup modes, then the thing might be the best friend you have, especially for a pitot-static problem. And then there's the flight path marker (FPM) produced by the inertial system, which show exactly where the jet is going without regard for any aerodynamic sensors.

I can not imagine seeing the FPM at the bottom of the indicator or HUD and not thinking about being fully stalled while holding back stick, can you?

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