futureatp
Topic Author
Posts: 189
Joined: Sun Feb 27, 2000 3:07 pm

Cycling Flaps On Ground

Wed Aug 28, 2013 9:35 pm

Just was on a flight (737-300) and something happened I have never seen before from a passenger window. I am just curious what was going on.

Push back from gate. Flaps set to takeoff setting. Then extended to about 15deg. Then retracted. Then extended to 25-30deg (remember Im eyeballing it from row 18...) about 3 or 4 times then retracted. Then set to takeoff. Depart normal. After landing, flaps were retracted and extended to around 10-15deg twice before arrival at gate.

Ive never seen this before as a passenger. I just curious if anybody had a guess as to what was going on. Company mechanic was in flight talking to crew as I deplaned.
 
KC135Hydraulics
Posts: 435
Joined: Sat Nov 03, 2012 2:05 am

RE: Cycling Flaps On Ground

Wed Aug 28, 2013 11:25 pm

Maybe it was some sort of inflight (sorta) ops checks due to maintenance performed. Or, maybe it was an "2nd verification" clearly done on the ground to verify if a maintenance write-up was infact legit or an anomoly.
MSgt, USAF
KC-135R / C-17A Pneudraulic Systems Mechanic Supervisor
 
musang
Posts: 788
Joined: Sun Apr 08, 2001 4:11 am

RE: Cycling Flaps On Ground

Thu Aug 29, 2013 10:25 am

In extreme cold weather, after engine start and before taxi, flaps are run out to 40 degrees (full) then back to zero, to check unobstructed movement. A close eye should be kept on the flap position needles to catch any asymmetry or disagreement with the flap lever position selected. The flaps are then extended to the take-off position, unless there is frozen precip, in which case they're kept retracted until just before line-up.

Regards - musang
 
113312
Posts: 580
Joined: Sat Apr 16, 2005 9:09 am

RE: Cycling Flaps On Ground

Thu Aug 29, 2013 3:39 pm

Most likely there was abnormal indications of slat position and they were running through the settings to verify the sequencing of the slats/flaps in all of those positions. Must have turned out to be OK otherwise you would have returned to the gate for maintence.
 
boeingfixer
Posts: 573
Joined: Fri Jul 29, 2005 2:02 am

RE: Cycling Flaps On Ground

Thu Aug 29, 2013 4:47 pm

Quoting musang (Reply 2):
In extreme cold weather, after engine start and before taxi, flaps are run out to 40 degrees (full) then back to zero, to check unobstructed movement.

Not all ops are that way. We routinely operate our B752's in -30C to -40C in the winter here and never do a full flap check as it's not needed.

Quoting 113312 (Reply 3):
Most likely there was abnormal indications of slat position and they were running through the settings to verify the sequencing of the slats/flaps in all of those positions. Must have turned out to be OK otherwise you would have returned to the gate for maintence.

This is probably the case here.

Ciao,

John
Cheers, John YYC
 
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HAWK21M
Posts: 29867
Joined: Fri Jan 05, 2001 10:05 pm

RE: Cycling Flaps On Ground

Thu Aug 29, 2013 7:59 pm

Probably finding an indication light not functioning as required......so recycling to check the problem.
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