View Full Version : Boeing 737NG alternate flap question
mamad
28th Mar 2012, 02:36
Hi guys
i have checked on boeing book for pilots and asked my instructor in vain
Question is : what is the electrical source of alternate flap on the Boeing 737NG
sorry if it has been covered i have not seen it
many thanks
ImbracableCrunk
28th Mar 2012, 03:51
AC Xfer Bus #2
mamad
28th Mar 2012, 20:17
Thanks
appreciate it
could you just provide your reference please
That would mean that in case you loose normal AC than you cannot extend your flaps ?
That would mean that in case you lose normal AC then you cannot extend your flaps ?
Correct. DC systems are not powerful enough to drive TE Flaps. I can confirm from my airplane wiring schematics that Xfr Bus 2 supplies AC power to the TE flap alternate drive motor.
Note that 28V DC Bus 1 is required for _controlling_ the supply of Xfr Bus 2 AC power to the TE flap drive motor and for powering the hydraulic bypass valve. However, if you lose AC Xfr Bus 1, you should still get DC Bus 1 power for flap control if the Bus Transfer Switch is in AUTO.
mamad
29th Mar 2012, 13:58
Thank you NSEU
that is very clear
cheers
de facto
1st Apr 2012, 14:01
That would mean that in case you loose normal AC than you cannot extend your flaps ?
If you also had a loss of your hyfraulic B pressure for the flaps drive unit that is.