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Becker Junior
15th Oct 2007, 20:36
If you are with a MEL released aircraft with one reverse thrust inoperative and you have a failure at the other engine during take off, you will have no reverse thrust during RTO. Is it right to say that you will have to deploy the speedbrakes manually as it is actuated by the reverse thrust levers?

I Just Drive
15th Oct 2007, 22:54
Without checking, I think its the closure of the thrust levers (once RTO is armed above 60 knots) that deploys the speedbrakes. Also, I think V1 is calculated for the stop scenario with no reverse either. I'm sure someone will correct me before I get the book out.

gonso
15th Oct 2007, 23:21
On a rejected take off, the speedbrakes must be deployed BEFORE reverse thrust, according to mr Boeing.

This is to prevent assymetrical reverse thrust (in the one engine scenario or the reverser u/s scenario) with the speedbrakes down which can cause control difficulties.

This is the reason why the speadbrake is not armed for t/o. It should be done manually, after thrust lever closure. Then reverse thrust follows. That's Boeing SOP anyway.

mustafagander
16th Oct 2007, 01:44
Our SOP is to raise ALL reverse thrust levers to the interlock, even if locked out. I'd be prepared to bet that most of us would do that without thinking, and voila - speedbrakes.

Wizofoz
16th Oct 2007, 04:52
I have worked for one company that had first deploying T/Rs, thus instigating auto spoiler deployment, as it's SOP, but every other Boeing operator I know of uses the Boeing reccomendation of manually deploying Speed Brakes first.

Also, Becker makes the statement that "If you are with a MEL released aircraft with one reverse thrust inoperative and you have a failure at the other engine during take off, you will have no reverse thrust during RTO."- Not so. There is no restriction on using the one operative T/R during an RTO. The assymetry is easily delt with by rudder and nosewhell steering.

Jausho
16th Oct 2007, 05:51
Also, Becker makes the statement that "If you are with a MEL released aircraft with one reverse thrust inoperative and you have a failure at the other engine during take off, you will have no reverse thrust during RTO."- Not so. There is no restriction on using the one operative T/R during an RTO. The assymetry is easily delt with by rudder and nosewhell steering.

I think the point Becker's trying to make, is that if reverse thrust is inop on engine 1 and the failure occurs on engine 2 - neither engine is able to provide reverse thrust; so he's right that you will have no reverse during a RTO... This makes assymetry a non-issue (but the extended distance reqd to stop a slight worry if the scenario wasn't accounted for in calculations).

Shiny side down
16th Oct 2007, 06:39
actions to initiate the RTO functions.
Close the thrust levers, simultaneously disconnect the Autothrottle,
Deploy the speedbrakes
Max reverse thrust (as appropriate)
Closing the thrust levers geets you into the RTO braking, which will be more than sufficent to stop, assuming correct speeds and performance are being used.
Deploying the speedbrakes- ensures any/all lift dumped.
Reverse thrust is purely an additional item in the performance. It makes no difference to the RTO braking effort, unlike the autobrake functions.

gonso
16th Oct 2007, 08:37
mustafagander says: "Our SOP is to raise ALL reverse thrust levers to the interlock, even if locked out. "
I do not know whether the MEL for the 737 is different where you fly, but isn't it an MEL requirement to wire lock the reverser lever so you cannot raise a locked out reverser lever?

Becker Junior
16th Oct 2007, 19:49
If you have a MEL released INOP reverse, it lever will be wired locked for sure. If you have a failure on the other engine, you won’t have reverse thrust for RTO. My SOP says that the PM should make the callout “speed-brake up or not up” during the RTO procedure. So assuming you leave it to work automatically. I agree we should deploy it manually BEFORE the reverse thrust is applied and that’s what I will do. SOP says also that you must leave the auto-brake RTO system to work until a complete stop as it is more efficient than maximum manual brake. On that I agree and the FCTM says so.