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View Full Version : VNAV Descent Speed Planning?


shockwave1973
23rd Apr 2010, 16:01
May someone please help to let me comprehend why VNAV will not command an economy target speed greater than 349 knots (VMO/MMO minus 16) or a pilot entered speed greater than 354 knots ( VMO/MMO minus 11) on the B747-400? I do not understand the logic behind it. Thanks in advance!

Intruder
23rd Apr 2010, 16:44
Maybe because the VNAV function nominally allows speed to vary +/- 15 KIAS to stay on the VNAV path in the descent...