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Old 27th Mar 2019, 07:17
  #754 (permalink)  
Join Date: Jul 2013
Location: Everett, WA
Age: 64
Posts: 2,418
Originally Posted by NSEU View Post
The maintenance manual and my 767 engineering training notes show no reference to the radio altimeters. Also, the logic for flaps and G/S capture is "or", not "and".

Most references show "flaps out of up" (although I do have one reference which says flaps >1).
The Flap/Slat Control Units on the 767 are relatively crude by current standards (not surprising - the basic design being nearly 40 years old). They put out analog discretes for 'flaps not stowed' - true anytime the flaps are not fully 'up', and 'flaps in landing' - true when flaps are ~23 degrees or greater (there may well be others - those are the ones that get used by the propulsion systems) - as well as digital outputs for use by systems such as EICAS. If anyone cares, on the engine side 'flaps not stowed' turns on continuous ignition, 'flaps in landing' selects approach idle - both via analog circuits (on newer aircraft this all gets done digitally).
There are two FSCU - Left and Right. Not sure about other systems, but the engines use left to left and right to right - so an FSCU failure only effects one engine.

IMHO the inadvertent TOGA selection is feasible, but this all remains conjecture until the NTSB releases something official.
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