HAWK21M From India, joined Jan 2001, 31851 posts, RR: 54 Posted (8 years 7 months 3 days 1 hour ago) and read 2646 times:
Since the B752 TE Flap & LE Slat mechanism is the same for both Hydraulic & Electric operation [Main & Alt],apart from the Hydraulic motor or Electric motor providing the drive.
Is there any way to know if the Electric motor has malfunctioned & the Hydraulic motor serviceable without operating Alternate flaps.
Also is there a fixed interval to test the Alt flap operation on this type or only post service check 500hrs.
Mender From United Kingdom, joined Feb 2004, 250 posts, RR: 0
Reply 1, posted (8 years 7 months 3 days ago) and read 2636 times:
Task card 27-063-01 is a 2000 hr check of the Alternate flap/slat system. Testing it after a 500 hr check is probably company policy. A good policy too in my experience.
I don't know of a way to check the electric motor without operating it. If there is it would be more work than operating it anyway.
If you do the test correctly it is quick and easy. Do it wrong and the system will lock out. If this happens just cycle the FSEU C/B's on P11 and you should be back in business. (This only usually happens during heavy maintenance when things are operated out of the normal config)
Boeingfixer From Canada, joined Jul 2005, 572 posts, RR: 0
Reply 3, posted (8 years 7 months 2 days 22 hours ago) and read 2622 times:
Quoting HAWK21M (Reply 2): Quoting Mender (Reply 1):
I don't know of a way to check the electric motor without operating it
Quoting HAWK21M (Reply 2): Thats the concern.How do you know that your Electric motor is u/s prior to flight.
The only way to do a confidence check of the Alternate Flap Motor is to operate the Alt. Flap system. Unless there is a suspected problem with the Alt. Flap system, it should be assumed that the system is functional. Especially if the previous maintenance inspection and functional checks were ok. The Alt. Flap system is one of the least used systems and the motor rarely fails. I've been working on Boeings for the past 10 years and have never had a failure of one on our fleet of 727's and the B757 system is very similar. The part that does fail for us is the hyd. flap motor bypass valve. This usually results in normal flap system failure.