Autospoilers 737

[Popolama]

if you land with the speedbrake lever set in down and not armed,upon touchdown when pulling the reverse levers the speed brake lever come up and all flt and grd spoilers are extended just as they were armed.
This only works when pulling the thurst reversers levers
i was tryin to find something about this on the manuals (ops2) but nothing.i m not sure how are you supposed to know this.Mr Boeing forgot to specify it in its book i guess.i heard we can find it in the maintenance manual...any ideas ?

[avioniker]

From SDS 27-62-00-001:

Automatic Operation

The auto speedbrake module controls the automatic operation of the speedbrakes. The auto speedbrake module uses data from these sources:
Speedbrake arming switch
Speedbrake refused takeoff switch
Antiskid/autobrake control unit (AACU)
Air/ground relays (2)
Antiskid sense relays (2)
Autothrottle switches (2).

The auto speedbrake module sends commands through relays to the auto speedbrake actuator during landings and refused takeoffs. The auto speedbrake actuator moves the speedbrake forward drum and lever brake. This causes the speedbrake lever to move. The input to the spoiler mixer and ratio changer is the same as the manual operation. This causes all the ground spoilers to move up, and a signal sent to the FDAU.

Indications

The auto speedbrake module controls the amber SPEEDBRAKE DO NOT ARM light and the green SPEEDBRAKE ARMED light. The SPEEDBRAKE ARMED light shows when the automatic operation of the speedbrake system arms correctly. The SPEEDBRAKE DO NOT ARM light shows when the automatic operation of the speedbrake system does not arm correctly.
The auto speedbrake module also sends signals to the FDAU for flight data recording, when the SPEEDBRAKE DO NOT ARMED or SPEEDBRAKE ARMED lights are on.
See the flight data recording system (FDRS) section for more information about the FDAU. ( SECTION 31-31)

The PSEU controls the amber SPEEDBRAKES EXTENDED light. This light comes on if the speedbrakes operate during approach.

And the Piece de resistance:

From SDS 27-62-00-006

SPEEDBRAKE CONTROL SYSTEM - SPEEDBRAKE RTO AND TAKEOFF WARNING SWITCHES

Purpose

The speedbrake RTO switch sends a signal to the auto speedbrake module. This operates the auto speedbrake function during refused takeoffs.
The speedbrake takeoff warning switch sends a signal to the proximity switch electronics unit (PSEU) for the takeoff warning function. See the takeoff warning section for more information on the speedbrake takeoff warning switch. (SECTION 31-53)

Location

The speedbrake RTO and takeoff warning switches are in the P10 control stand. To get access, remove the manual stabilizer trim wheel and the panel on the left side of the control stand.

Physical Description

The speedbrake RTO switch operates when the thrust reverser levers move to the reverse thrust position. The thrust reverser levers move the thrust reverser cam. The cam rotates the cam follower. The cam follower rotates the lifting arm and operates the speedbrake RTO switch. The lifting arm hits the lifting tab, and this lifts the speedbrake lever.

The speedbrake takeoff warning switch operates when the speedbrake lever moves out of the down detent. An actuating arm on the speedbrake lever operates the speedbrake takeoff warning switch when the speedbrake lever moves down into the down detent.

I don't know what happened to the information but it used to be in Volume 2 of the POH, chapter 9.

[mono]

My guess is you will find an explanation in your ops manuals but under the T/O section rather than Landing.

Other than that avioniker seems to have it covered.:ok:

[Popolama]

thanks a lot avioniker that was a complete answer...

[Flight Detent]

Hi all,
Doesn't the RTO require 90+ knots, I remember that because of the THR HLD actuation at 84 knots!

Cheers

[wing737]

You can find it at 737 operations manual volume 2,chapter 9(Flight Controls)page 9.20.14(might differ depending on the update)

[Popolama]

well i have the udpate of june6,2003 and it talks about speed brakes in page 9.20.12 and 13 but nothing about landing with speed brake not armed.it s only about flt and ground ops and during RTO.any one has a newer update ?

[tames oud]

i have a sept 30 update. On page 9.20.16 it specifies the conditions for speedbrake deployment during landing.

On page 9.20.17 i found the conditions for the auto speed brake system to work with the lever in the down postion during landing or rejected take-off.

main landing gear spin up (>60 kts)
both thrust levers retarded to idle
reverse thrust levers positioned for reverse thrust

hope this helps

[Hudson]

I was surprised to read that in relation to the B737 rejected take-off procedure, a major airline in Australia relies on actuation of the reverse thrust levers as the first action to raise the ground spoilers, rather than go along with the Boeing recommended procedure in the QRH NNM.1.2 - which calls for the speed brakes to be raised manually.

Surely manual extension is the most efficient and timely method of raising ther speed brakes in an abort. The FAR take-off diagram in the 737 FCTM page 2.29 indicates that the speed brakes are manually deployed after the throttles reach idle.

Is there any other operator that chooses to rely on reverse thrust lever operation to raise the speed brakes in lieu of manual speed brake operation - and for what operational reason?

[Ivan Urge]

Hudson. Air New Zealand and Japan Airlines do it that way as well on all their Boeings. The rationale is that there is an automatic system so let it do its job, the speedbrakes are deployed immediately and fully (a hand yanking it sometimes doesnt get it all the way up in the rush) upon selection of reverse and that there are only two actions required, not three.

[alexban]

Hudson. Think about the rejected take-off film.The captain performs the rejected take-off manouvre (as said in the FCTM) .So ,he disengage the AT,retard thrust levers ,apply max brake or monitor autobrake then raise speedbrake !.If RTO speed was more than 60 kts the speed brake will raise automatically when thrust levers will be positioned for reverse thrust ( OM2).
Well,if speed is below 60 kts,deployment of the speed brakes should be make manually,but will have practically no efect,due to slow speed at RTO.
The procedure you said (QRH NNM 1.2 ) is to make sure that the automatics worked well.If it didn't work ,then you should raise speedbrakes manually.
I wonder how you do this in simulator,what are your manouvers in order to raise the speeds before the automatics do it? Maybe the FO do it? Or you use the left hand ? :) cause the right one is on the thrust levers,and reversers.Or raise the speedbrake first,then aplly reverse thrust ? Which I think would be very dangerous in real life.
brgds Alex

[Popolama]

RTO
1/AT off thurst Idle,2/speed brake UP manually if not deployed,3/Full brakes,4/reverse thrust
that s our procedure
i am not sure about it but i think that when retarding to idle the spoilers come up automatically without using reverse....that s what i found out in the sim

OM2 :"During RTO the autospeedbrake system operates when these conditions occur:
main landing gear wheels spin up(more than 60 kt)
takeoff is rejected both thrust levers retarded to IDLE and the reverse thrust lever positioned for reverse thrust,speed brake lever automatically moves to the UP position and all spoilers deploy" June6,2003


not sure about it but i think retarding to IDLE ONLY can make the speed brake lever to go UP.no need to use reversers