OVERTALK
7th May 2010, 05:29
FBW /APU starting and controllability?
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When the A320 went into the Hudson River, the Captain deviated from the checklist cadence and quite appropriately fired up the APU, more or less immediately after the birds hit.
This action kept electricals (and hydraulics?) and retained(?) the FBW mode as NORMAL Law (????).
What if he hadn't started the APU? Would sufficient busses have been powered and would battery power for the 5 min flight have been enough? Would the crew have had their full FBW or have been reverted to a lesser law?
The inference, albeit a weak allusion, from the NTSB's Report was that it may well have been a completely different outcome if Capt Sully hadn't promptly kick-started the APU. As it was, he had significant problems maintaining the desired/appropriate glide speed and the flare-speed (and thus the touchdown attitude) was non-optimal. Why was that?
But if the APU hadn't been started, the degree of controllability that led to a "sufficient" flare (although not optimal - NTSB Report) and subsequent benign ditching might well have been characterised as a crash.... with a significant loss of life due to a greater loss of airframe integrity.
Your thoughts? and some supporting A320 relevant facts?
.
.
When the A320 went into the Hudson River, the Captain deviated from the checklist cadence and quite appropriately fired up the APU, more or less immediately after the birds hit.
This action kept electricals (and hydraulics?) and retained(?) the FBW mode as NORMAL Law (????).
What if he hadn't started the APU? Would sufficient busses have been powered and would battery power for the 5 min flight have been enough? Would the crew have had their full FBW or have been reverted to a lesser law?
The inference, albeit a weak allusion, from the NTSB's Report was that it may well have been a completely different outcome if Capt Sully hadn't promptly kick-started the APU. As it was, he had significant problems maintaining the desired/appropriate glide speed and the flare-speed (and thus the touchdown attitude) was non-optimal. Why was that?
But if the APU hadn't been started, the degree of controllability that led to a "sufficient" flare (although not optimal - NTSB Report) and subsequent benign ditching might well have been characterised as a crash.... with a significant loss of life due to a greater loss of airframe integrity.
Your thoughts? and some supporting A320 relevant facts?