Hi all,
Is anyone able to tell me, how long a duration (eg 2 sec) the "RA rate of change" must remain in the Warning Envelope range for, in order for the aural warnings to sound?
I understand some airlines do suffer nuisance warnings at some otherwise flat enviornment because of small rising hills etc just before the threshold.
Surely it wont sound if the instantaneous RA change at 500' RA is 3000 ft/min for 0.1 second due to a sloping roof of a house located short of the runway...
I just thought if I knew roughly how long that rate must be sustained, I could somewhat anticipate the coming of the warning that's all... May be too inpractical and academic but worth asking what with all the bus experts on pprune
Cheers