PPRuNe Forums - View Single Post - AF447 wreckage found
View Single Post
Old 30th May 2011, 13:04
  #1035 (permalink)  
goldfish85
 
Join Date: Nov 2009
Location: Near Puget Sound
Age: 86
Posts: 88
Likes: 0
Received 0 Likes on 0 Posts
Quote: According to the BEA report, the AOA was indicated at 4 degrees as they went over the top. Since this is the primary driver of the stall warning, the warning would likely have shut off, no matter what the speed was, and even if they didn't disable it a low speed.

This is interesting. In researching FBW accidents for a presentation to ISASI, there was an A-340 (with similiar control laws) that triggered Angle-of-attack protection during cruise at FL360 over the north Atlantic. Once AoA protection is invoked, zero stick input will cause the airplane to maintain alpha-prot (about 4 something AoA). Since AoA at cruise is about 1 degree, this will result in a zoom. In the A-340 case, it zoomed over 2000 ft before the pilot could recover.

Now I know the airplane was reported to be in alternate law (AoA protection not available), but I would still wonder. I think we need to let BEA figure all this stuff out.

One more thing. There have been references to the NWA B-727 which departed KJFK with the pitot heat off. This was a colleague of mine and, at the time, I wondered "how could he be so dumb?" Well a year or so later, I found out just how dumb on can be. When all sorts of contradictory information is present from various failures, it is very easy to latch onto one conclusion and only see those facts that support that conclusion and ignore those that don't.
goldfish85 is offline