smartt1982
Topic Author
Posts: 226
Joined: Sat Nov 24, 2007 11:17 pm

737, A/T And Limit Speeds Qs

Thu Jul 12, 2012 5:54 pm

With the auto throttle on the 737 does it always take its inputs from the captains side no matter what or was this just something that would be the case depending on the model of the 737? I know on the Turkish Airliner crash into EHAM the throttles retarded because of the faultly RA on the captains side, is this always the case no matter what, the A/T will always take inputs from the captains side?
Is this the same for the limit speeds for the Flap blowback, were will the Flap system it take its inputs from in order to decide to do a blowback or not? (Captains or FOs PFD?)
 
roseflyer
Posts: 9606
Joined: Fri Feb 13, 2004 9:34 am

RE: 737, A/T And Limit Speeds Qs

Thu Jul 12, 2012 7:43 pm

Quoting smartt1982 (Thread starter):
With the auto throttle on the 737 does it always take its inputs from the captains side no matter what or was this just something that would be the case depending on the model of the 737? I know on the Turkish Airliner crash into EHAM the throttles retarded because of the faultly RA on the captains side, is this always the case no matter what, the A/T will always take inputs from the captains side?

There was a software change with an associated Service Bulletin that changed the FCC/Autothrottle Computer to use inputs from both sides as a result of that crash.
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N243NW
Posts: 1597
Joined: Thu Jul 24, 2003 4:29 am

RE: 737, A/T And Limit Speeds Qs

Sat Jul 14, 2012 3:06 am

Quoting Roseflyer (Reply 1):

There was a software change with an associated Service Bulletin that changed the FCC/Autothrottle Computer to use inputs from both sides as a result of that crash.

Correct, for the Rockwell Collins aircraft that are the most recent. For older aircraft that use the GE (Smiths) autothrottle computer, a separate service bulletin is said to be in the works but has not yet been released. There's also a service bulletin for the EGPWS that adds an audible "AIRSPEED LOW" callout so pilots have more warning of an impending stall.

Quoting smartt1982 (Thread starter):
Is this the same for the limit speeds for the Flap blowback, were will the Flap system it take its inputs from in order to decide to do a blowback or not? (Captains or FOs PFD?)

The flap blowback (flap load relief) function that you describe works through the FSEU and left ADIRU, so if the captain's air data system is not working properly, flap load relief will not be available.

[Edited 2012-07-13 20:10:46]
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