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Old 18th Apr 2017, 19:55
  #3521 (permalink)  
woodpecker
 
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ˆˆ at 7 h 20 min 50, the selected altitude decreased to 100 ft for three seconds and then increased to the maximum value of 49,000 ft and stabilized again at 35,000 ft;
ˆˆ at 7 h 21 min 10, the Bordeaux control centre gave the crew the instruction to continue the descent to flight level FL210;
ˆˆ at 7 h 21 min 16, the selected altitude was 21,000 ft;
ˆˆ from 7 h 22 min 27, the selected altitude was 100 ft most of the time and changed several times until it stabilized at 25,000 ft at 7 h 24 min 13;
ˆˆ at 7 h 24 min 15, the buzzer to request access to the cockpit was recorded;
ˆˆ at 7 h 24 min 29, noises like those of the unlocking of the cockpit door then its opening was recorded and corresponded to the Captain’s return to the cockpit;
ˆˆ at 7 h 25 min 32, the flight was transferred to the Barcelona en-route control centre and the crew was instructed to descend to FL170;
ˆˆ at 7 h 26 min 16, the aircraft was put into a descent to its newly cleared flight level and the flight continued normally.
Due to the engaged autopilot modes, the changes in selected altitudes described above did not influence the aircraft descent flight path.
Being a Boeing driver I am confused by the above statement that "the changes did not influence the descent path".

If the descent was initiated to FL 350 and 100 feet selected "in the window" the a/c would continue as commanded towards FL350, but, if the "window" height was increased, as suggested, to 49000 feet, on a Boeing, the A/P would have discontinued the "v-nav" descent and reverted to "Alt Hold". Surely the same would have occurred on an Airbus!

Over to you bus drivers...
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