Detpilot says:

Sure sounds good. But this is absolutely not what alpha floor does... Do you have an Airbus type? First, it's wrong. Alpha floor is an auto thrust only function. Second, it's inhibited below a certain altitude (although the gear being up might have blocked that inhibition, been off the plane for a while).

My understanding was that the airplane was in alternate law at impact, due to the hydraulic issues and being single generator. I could be wrong, sure. But, you're throwing alpha floor around like someone who hasn't flown the bus, which casts doubt on the rest of your "analysis


US Airways Training Manual
RC-7 Page 58


High Angle of Attack Protection

Under Normal law, when the angle of attack becomes greater than αprot, the system switches elevator control from normal mode to a protection mode, in which the angle-of-attack is proportional to sidestick deflection. That is in the αprot range, from α-prot to α MAX, the sidestick commands α directly. However, the angle-of-attack will not exceed αMAX, even if the pilot gently pulls the sidestick all the way back. If the pilot releases the sidestick, the angle-of-attack returns to αprot and stays there. This protection against stall and windshear has priority over all other protections. The autopilot disconnects if the α protection is active.

Detpilot is correct that Alpha floor – is a thrust condition protection only. My bad, so sorry. There is α-floor, αprot, αMAX. They are crowded together in the “tiger tail” a black and amber band on the airspeed tape. Vαprot at the top and VαMAX at the bottom. Sully remained in the Alpha Protection range which allowed him to use full back stick prior to impact while not exceeding Alpha Max.

Yes I do have an Airbus Type and considerable time in type in both seats.Your correction sent me back to the manuals, in a corner of the basement. However I have been retired for several years and as you know the Airbus is easy to fly and sometimes hard to understand. Sully stated, but I have no reference, that he started the APU both for an opportunity for a start and to protect Normal law in the ditch. Some cabin lighting and the galleys were load shed when the aircraft went to single generator. There were two generators available immediately prior to impact, the APU and engine #1.

Condition of the Aircraft at water impact.

http://www.exosphere3d.com/pubwww/pd...ket/441039.pdf

Page 1 of 54Submission to the National Transportation Safety Board For theUS Airways Flight 1549 A320-214 N106US Landing in the Hudson River Weehawken, New Jersey January 15 2009 Accident Investigation
AIRBUS S.A.S

• This multiple bird strikes led to a loss of thrust on both engines to the extent that continued level flight could not be maintained. However the N2 of engine number 1 was still at a level sufficient for its associated electrical generator (–IDG-) to remain on-line.
• The crew immediately started the APU, and followed the QRH “ENG DUAL FAILURE” procedure.
• During the remaining portion of the flight, the Aircraft remained in Normal Law, and on occasion was flown within the alpha protection range. Notably from approximately 150 ft down to the water impact the Aircraft was in slats/flaps configuration 2. During this time period the Aircraft was in the alpha protection mode which allowed the flight crew to remain focused on their priorities, conversely if the Aircraft had been a non fly-by-wire aircraft, the flight crew would have had to fly in and out of the stick shaker to maintain the desired descent profile.
• The QRH “ENG DUAL FAILURE” procedure has been designed for events occurring at high altitude, with enough time to go through the complete procedure. It is not designed for emergency situation such as the one experienced during this event. •The cockpit crew had insufficient time to complete the “ENG DUAL FAILURE” check-list

It is important to note that the electrical generation provided by the engines through the IDG’s remains on line as long as its respective engine N2 remains above 56.3 %. During this event, the engine N°1 IDG remained on-line up to the time of the engine N°1 re-start attempt. From the APU Master Switch selection to ON and the APU start, it normally takes approximately 1 minute for the APU Electrical generation to become available. The DFDR data, confirms that the APU electrical power was already available at the time of the engine N°1 re-start attempt took place, thus allowing the aircraft to remain in Normal law, and all displays to remain available to the crew.

https://data.ntsb.gov/Docket?ProjectID=73240

Project Summary: Aviation Investigation - 123 Docket Items - DCA09MA026
Description: USAirways flight 1549, Airbus Industrie A320-214 equipped with CFM engined ditched in Hudson River on takeoff from LGA
Mode: Aviation
NTSB Number: DCA09MA026
Date of Accident: 01/15/2009
City: Weehawken
State/Region: NJ
Country: United States
Project Type: Investigatio



https://data.ntsb.gov/Docket?ProjectID=73240

Captain Sullenberger stated he attempted to start APU and believed he heard an electrical transfer but was not aware if RAT deployed. He said they selected flaps to 2 for landing, he thought he felt the flaps but did not recall if he checked the ECAM to confirm if flaps got to 2.


















Note the placement of the APU start about one-third of the way down the QRH checklist.