Go Back  PPRuNe Forums > Flight Deck Forums > Tech Log
Reload this Page >

RTO in a 737 NG

Tech Log The very best in practical technical discussion on the web

RTO in a 737 NG

Old 29th Jun 2010, 14:58
  #1 (permalink)  
Thread Starter
 
Join Date: Apr 2008
Location: Miami
Posts: 13
Cool RTO in a 737 NG

How do you perform an RTO in a 737NG?
I know that the QRH states to deploy the speedbrakes manually, but is it legal to do it using the autospeedbrake feature, using the reverser?
I know of some major airlines (eg. Air New Zealand, Japan Airlines) that reject, reaching for the reverser first.
Cptn Titus is offline  
Old 29th Jun 2010, 15:25
  #2 (permalink)  
 
Join Date: Feb 2007
Location: Twlight Zone
Age: 66
Posts: 20
With RTO selected the speedbrake will deploy automatically during an RTO. It is the Captain's responsibility to insure the speedbrake deployed during the rejected T/O procedure. Basically, it's autothrottles - OFF, throttles - IDLE, thrust revers - DEPLOY, then check the speedbrake is deployed. There are a lot of other things that need to be done, like note airspeed at the time of reject, call the tower, run the RTO checklist, etc., etc., but above are the basics.
Boneman is offline  
Old 29th Jun 2010, 16:03
  #3 (permalink)  
Per Ardua ad Astraeus
 
Join Date: Mar 2000
Location: UK
Posts: 18,581
The two most important things in an RTO are:
Brakes and
Spoilers
Reverse is secondary.

Boneman - I think you will find that Boeing actually task the F/O with ensuring the speedbrake has deployed and the Captain with doing so(/anyway) if it has not? Your airline may of course differ.

In fact. C Titus, as you will be aware it happens PDQ, BUT there is a sequence where from closing the throttles, F/O checking bits done (including spoilers) and the hand going to 'backup' the action of the autospeedbrake - the hand then goes back to the throttles and on with the reverse.
BOAC is offline  
Old 29th Jun 2010, 16:04
  #4 (permalink)  
Thread Starter
 
Join Date: Apr 2008
Location: Miami
Posts: 13
Ok, but what would an FAA Inspector say, if I don't deploy the speedbrakes manually, as the QRH states? Would he fail you? Does anyone know how Boeing would respond to this?
Thanks for your inputs!!
Cptn Titus is offline  
Old 29th Jun 2010, 16:06
  #5 (permalink)  
 
Join Date: Oct 2006
Location: Europe
Posts: 36
ORH says "Raise the SPEED BRAKE lever"
Then "Apply maximum reverse thrust consistent with conditions".
So, first speed brake, then reverse. Of course, when you select reverse, the speedbrake lever will go up, but the sequence should be first speedbrakes, then reverse.
yrvld is offline  
Old 29th Jun 2010, 16:08
  #6 (permalink)  
Per Ardua ad Astraeus
 
Join Date: Mar 2000
Location: UK
Posts: 18,581
We crossed. If they had not automatically deployed and you didn't - I would hope so! Most people 'back it up' anyway after throttles. If it has deployed so much the better.
BOAC is offline  
Old 29th Jun 2010, 16:13
  #7 (permalink)  
Thread Starter
 
Join Date: Apr 2008
Location: Miami
Posts: 13
Right guys. But what I mean is, what's the point of having such a great automatic feature which could make a difference in real life, and not using it?
Cptn Titus is offline  
Old 29th Jun 2010, 17:07
  #8 (permalink)  
Per Ardua ad Astraeus
 
Join Date: Mar 2000
Location: UK
Posts: 18,581
I think you might be a bit confused? Have you actually done an RTO in the sim? The spoilers will be deployed before you can blink (- or say 'Airbus'). The thing is to have your hand going to the lever without delay IN CASE the auto does not work. After all, you cannot raise something that is already raised
BOAC is offline  
Old 29th Jun 2010, 17:26
  #9 (permalink)  
Thread Starter
 
Join Date: Apr 2008
Location: Miami
Posts: 13
Of course Boac, I totally agree with you, but I am talking about the legal part. In practical terms in the simulator, it is as you say. But the fact is the instructor or FAA inspector is actually looking at your hands!! and might call your attention if you don't "manually extend the speedbrake". So, does anyone experienced in the box something like this?
Tks
Cptn Titus is offline  
Old 29th Jun 2010, 17:30
  #10 (permalink)  
 
Join Date: Mar 2006
Location: Germany
Posts: 10
What´s the reason for noting the brake on speed? Brake cooling times?
pilotguy32 is offline  
Old 29th Jun 2010, 17:35
  #11 (permalink)  
Per Ardua ad Astraeus
 
Join Date: Mar 2000
Location: UK
Posts: 18,581
Yes - but the point is you should be moving your hand anyway to be ready, so he/she should see that? When your hand gets there - the lever has gone. It certainly does no harm in giving it a 'tug' anyway which might satisfy this inspector - if they are that pedantic. I cannot see the issue.
BOAC is offline  
Old 29th Jun 2010, 17:41
  #12 (permalink)  
Thread Starter
 
Join Date: Apr 2008
Location: Miami
Posts: 13
Well BOAC...it happens you know....they could be quite pedantic!
Pilotguy32: Exactly!
Cptn Titus is offline  
Old 29th Jun 2010, 18:32
  #13 (permalink)  
 
Join Date: Jun 2001
Location: UK
Posts: 3,968
From the B737-800 manual:-

If the SPEED BRAKE lever is in the DOWN position during landing or rejected
takeoff, the auto speed brake system operates when these conditions occur:
• main landing gear wheels spin up (more than 60 kts)
• both thrust levers are retarded to IDLE
• reverse thrust levers are positioned for reverse thrust.

So speedbrakes will not deploy until reverse thrust selected. This is surely to back up in case speedbrake is not manually selected?

Also:-

• Simultaneously close the thrust levers and disengage the
autothrottle
• Apply maximum manual braking or verify operation of RTO
autobrakes
• Manually raise the speedbrake lever
• Apply maximum reverse thrust and stop the aircraft.
fireflybob is offline  
Old 29th Jun 2010, 22:22
  #14 (permalink)  
 
Join Date: Aug 2006
Location: South
Posts: 636
I know of some major airlines (eg. Air New Zealand, Japan Airlines) that reject, reaching for the reverser first.
I can confirm that Air NZ do not have that procedure for any Boeings

It is:
  1. Close thrust lever and cancel A/T
  2. Raise speed brake
  3. Ensure braking
  4. Select reverse thrust
c100driver is offline  
Old 30th Jun 2010, 07:07
  #15 (permalink)  
 
Join Date: Nov 2001
Location: KUL
Posts: 214
C.Titus,

This subject was brought up in a mini-symposium at our company last month. According to Boeing Chief Technical Pilot, the reject action is exactly as published in the manuals, in the exact sequence i.e. as posted by fireflybob & c100driver.

However, Boeing has done tests to verify the validity of current reject data using 2 steps reject action i.e. 1. disengage A/T & close thrust levers 2. select reverse. Apparently, for all current boeing types EXCEPT the 737 (all-variants), the stopping distances are negligible.

If your airline wishes to adopt the 2 steps reject action, all you need to do is to write to boeing for a NTO.

Hope this helps.

SR
SuperRanger is offline  
Old 30th Jun 2010, 07:36
  #16 (permalink)  
Thread Starter
 
Join Date: Apr 2008
Location: Miami
Posts: 13
Thank you, very much SR!!
Cptn Titus is offline  
Old 30th Jun 2010, 13:43
  #17 (permalink)  
short flights long nights
 
Join Date: Aug 1999
Posts: 3,208
For what it is worth our 777 procedure has changed from "pull the speedbrake manually and then select reverse" to " select reverse and check auto deployment of the speedbrake"
SOPS is offline  
Old 30th Jun 2010, 13:52
  #18 (permalink)  
 
Join Date: Feb 2007
Location: Twlight Zone
Age: 66
Posts: 20
Verbatum:

During takeoff, the crewmember recognizing the malfunction will call it out
clearly and precisely.

CAPTAIN
Calls “REJECT”
Simultaneously brings both thrust levers to idle and disengages the autothrottles.
Confirms RTO braking or initiates maximum manual braking.
Initiates maximum reverse thrust consistent with runway and aircraft conditions.
Raise speedbrake lever if not already up.
Announces “MANUAL BRAKES” when autobrakes disengage.
Calls for “REJECTED TAKEOFF CHECKLIST.”

FIRST OFFICER
Confirms the following actions:
· Both thrust levers idle.
· Autothrottles disengaged
· RTO or manual brakes.
· Reverse thrust:
· (Calls if other than both reversers operating normally, such as “LEFT
REVERSER ONLY.”)
· Speedbrake lever full up. (If speedbrake lever is not up calls “SPEEDBRAKES.”)
Call “80 KNOTS.”
Calls “MANUAL BRAKES” if not called by the Captain.
Notify Tower/Ground of reject and status.
Notify cabin to “REMAIN SEATED, REMAIN SEATED.”
Accomplish REJECTED TAKEOFF checklist.
* * * *
Boneman is offline  
Old 30th Jun 2010, 15:32
  #19 (permalink)  
 
Join Date: Jul 2004
Location: Between heaven and hell
Posts: 239
The 2 step process (thrust levers to idle, apply reverse thrust and check SB up) seems logical to me (but obviously not to Boeing).

Reversers unlocked, automatically mean thrust levers are in idle position and unable to move forward at least on the 737.

As for the autobrake, a 90kts instead of an 80kts call during the T/O roll would apparently be more useful on the 737 as the A/B system won't kick in below that speed.
ant1 is offline  
Old 1st Jul 2010, 14:05
  #20 (permalink)  
 
Join Date: Jun 2000
Location: Australia
Posts: 4,138
This is surely to back up in case speedbrake is not manually selected?
Precisely that. The reason why Boeing require the speed brake to be actuated manually is that if the auto speed brake function fails to operate you already have the speed brakes deployed. The speed brake/spoiler combination is vital in a high speed abort to get the weight on the wheels for efficient braking as well as the drag effect at high speed. Interestingly Qantas used to require the reverse thrust action to activate the speed brake rather than first applying manual speed brake. This was in contradiction to the Boeing philosophy which has been in the FCTM since years ago. But Qantas has now reverted back to the original Boeing advice of manual speed brake followed reverse thrust where necessary.

Interestingly in the simulator we have observed on many occasions that some pilots rely totally on the operation of the thrust reverser levers to actuate the auto speed brakes on an abort or landing. But the malfunction section on the simulator instructors panel includes a facility to disable the auto-speed brake function. Clearly the certification of the simulator includes the possibility of the auto speed brake malfunctioning. Otherwise why have that malfunction capability? One thing is for sure and that is pilots who rely on the reverse levers to auto actuate the speed brakes often get a shock when they find out seconds later the speed brakes failed to operate automatically. Valuable efficient braking time is lost before someone spots the fact the speed brakes did not operate.

On another point of technique and this is in regard to disengaging the autothrottle system as part of the abort take off procedure. Once throttle hold is annunciated during the take off run, closure of the throttles can take place without the risk of the throttles opening up again during slow down.

But the FCTM states "After THR HLD is annunciated, the thrust levers, when retarded, remain in idle. For procedural consistency, disengage the autothrottles for all rejected take offs".

But what often happens in the simulator when an abort is initiated at high speed is the pilot first presses the disengage button and then rapidly closes the throttles. There is often a slight delay of maybe one or two seconds as the the pilots thumb hits the disengage button in the throttle handle and then he closes the throttles. That slight delay at 140 knots means the aircraft is still accelerating over 200 feet per second before the throttles are whipped closed. The FCTM also states: "if the takeoff is rejected before the THR HLD annunciation, the autothrottle should be disengaged as the thrust levers are moved to idle. [COLOR="Red"]

It does not say before the thrust levers are moved to idle. In other words the pilot should close the throttles and as time permits disengage the autothrottles - as Boeing says "for procedural consistency". There is nothing to say you cannot close the throttles fully and then disengage the AT system.
Centaurus is offline  

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information -

Copyright © 2021 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.