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USAir 1549 and Alpha Protection

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AC560

Well-known member
Joined
Dec 9, 2005
Posts
1,184
Idle curiosity on how this worked for that flight if any Airbus guys can give a little insight would be appreciated.
 
Alpha floor is inhibited below 100 feet RA, cannot remember if it also requires gear down, however, A. Floor is only an auto thrust function, which will command TOGA power, of course there was no power available.

AoA protection would have been available, but based on the AoA during approach and touchdown, it more than likley did not become active, it would have lowered the nose.

BTW, the A320 crash in Mulhouse was caused by A.floor being inhibited below 100 ft. RA. The pilot in that case was planning on it kicking in, not understanding the system well enough to know that it wouldn't. Moments before it became a tree destroying chain saw, you can hear the engines spooling up, because the TL's were pushed to TOGA.

If you want more info, I'll go dig out the book!
 
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That Air France crash is very misunderstood and everyone blames it on the computer, but it was really pilot error if I remember correctly. He was also flying way below the altitude they had planned on for the flyby. I think they committed a few other errors, but I can't remember them off the top of my head. I think the Airbus got a bad rep for nothing from that crash.
 
I'm not familiar with the AB. Did the crew have to listen to a Gear horn in the flare or is there a way to inhibit it?
 
I'm not familiar with the AB. Did the crew have to listen to a Gear horn in the flare or is there a way to inhibit it?

They had a Ground Prox warning until splash down, as I read it. I am really anxious to see the CVR trans script. So many questions.
 
That Air France crash is very misunderstood and everyone blames it on the computer, but it was really pilot error if I remember correctly. He was also flying way below the altitude they had planned on for the flyby. I think they committed a few other errors, but I can't remember them off the top of my head. I think the Airbus got a bad rep for nothing from that crash.

You should read the actual report before commenting.

Though pilot error was certainly a factor, some of the flight control software and FADEC controls were changed after this incident. Think slats out - approach idle.
 
Well, I'm just going off my memory from when we studied it 8 years ago...so my apologies, sir. My point was that if he wasn't flying at 30' (below the tree tops) it wouldn't have happened.

Here's an excerpt from airdisaster.com, though:
The crew started the descent three minutes later and Habsheim was in sight at 450ft agl. The first officer informed the captain that the aircraft was reaching 100ft at 14:45:14. The descent continued to 50ft 8 seconds later and further to 30-35ft. Go-around power was added at 14.45:35. The A320 continued and touched trees at the end of the runway at 14:45:40 with a 14° pitch attitude and an engine speed of 83% N1. The plane sank slowly into the forest and a fire broke out. Failure of the Captain to maintain sufficient altitude and airspeed for recovery after a low approach to a runway with obstacles near the departure end.

I know that there were some automation anomalies that were discovered also. What are your opinions?
 
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Would have been in alternate law..no protections in place, only slow/high speed "stability" features..he would have had to maintain at least 140kts for the RAT to be functioning.

alpha floor does not depend on LG position..in normal law works gear up or down when the RA is above the appropriate threshold..

At Habshiem there were automation "understanding" anomalies..and lack of an "approach idle" feature when TOGA was finally selected, the engines simply didnt spool up in time..and yes they were below the "alpha floor" RA threshold..

smart cockpit.com will clear up all misunderstandings/misconceptions of the 'bus..as a former Boeing pilot, I find the 'bus automation to be rather fantastic..just the plane itself is rather plastic..
 
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Would have been in alternate law..no protections in place, only slow/high speed "stability" features..he would have had to maintain at least 140kts for the RAT to be functioning.

alpha floor does not depend on LG position..in normal law works gear up or down when the RA is above the appropriate threshold..

At Habshiem there were automation "understanding" anomalies..and lack of an "approach idle" feature when TOGA was finally selected, the engines simply didnt spool up in time..and yes they were below the "alpha floor" RA threshold..

smart cockpit.com will clear up all misunderstandings/misconceptions of the 'bus..as a former Boeing pilot, I find the 'bus automation to be rather fantastic..just the plane itself is rather plastic..

As has been widely reported, one of the engines was still running at 35%. All buses were powered and the aircraft would of stayed in normal law with all protections.
 

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