737 Flap Asymmetry questions

[Vessbot]

Originally Posted by oicur12.again

Greetings all,

I will soon be returning to the sim and will be seeing a flap failure for the first time since my initial training 2 years ago.

It seems rather straight forward and the Boeing QRH is easy to step through however I do have some questions I would like to throw at the experts.

1. With a TE Flap Assy it suggests that normal operation can be continued if the Assy indication is removed after setting the flap handle to the nearest detent (equal to or less than). Our manual states that in the case of Assy “hydraulic power is removed” so I am assuming that hydraulic power is restored simply by moving the flap handle again in response to the QRH?
2. What would cause an Assy condition that could be cleared by moving the flap handle?

And a bonus question:

3. Our manuals/QRH have no information about brake cooling times and I am intrigued that this would not become a factor following an RTO. Do Boeing not provide these?

Cheers and thanks for any guidance that can be provided

I had a thought, that might resolve the discrepancy. I looked in my (also company-modified) QRH, and maybe someone with access to a pure Boeing one can also follow me through this.

Which exact checklist are you looking at? Mine has separates ones for:
"Trailing Edge Flap Asymmetry," and "Trailing Edge Flap Disagree"

Do you have these, or are they combined into one?

My "Asymmetry" checklist (like yours) has the first step to set the lever to the nearest equal/less detent than what's indicated, and (like everyone else on the thread) has no statement about restoring function... which also matches the system description of asymmetry protection permanently disabling TE flap movement.

However, the "Disagree" checklist does have the possibility of restoring function. First it also directs you to set the lever to a lower detent, then "Choose one" with the first choice being "Flaps move as commanded." And this matches the system behavior of the Flap Load Relief Lockout function, which stops TE flap movement if selected at too fast of an airspeed, but then (unlike asymmetry protection) movement is restored by going to a lesser detent than current displayed position.

I see the possibility of these checklists being mixed together and creating confusion (either by the resulting checklist being simply wrong, or being right but creating easy error from too many "choose one" decisions being followed wrong), or... a language barrier and/or false memory, where you should have done the Asymmetry checklist but are remembering the Disagree checklist... which both words sound very similar, but are different. In Asymmetry, the flaps are different from each other (and movement can not be restored) while in Disagree, the flaps are the same as each other, but disagree with the detent (and motion can be restored).