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Woodreau wrote:I cannot comment on the specific 737 procedures on rejecting a takeoff, I think the instructor would prefer the pilots to expeditiously retard the thrust levers to idle and deploy the speed brake rather than slamming the throttles back and pulling the speed brake handle.
GalaxyFlyer wrote:Airplanes are flown with pressures applied with fingertips, not fists slamming controls around, that’s the difference.
As the throttles are retarded, the handling pilot has to remove the rudder to avoid swerving into the applied rudder that isn’t opposing thrust any longer. It’s a coordinated action, not independent ones. Get the power off, plane straight, then deploy the stopping devices, speed brakes and wheel brakes.
GalaxyFlyer wrote:No, just need to get the plane tracking straight. I was considering manual braking, RTO function will do its job while you do yours. If there’s an RTO function, it almost certainly has auto spoilers, the pilot is just backing up the auto function.
GalaxyFlyer wrote:Yup
bigb wrote:I can comment on the 737, but the 747 and I know 777. The speed brakes will auto deploy in the event of a RTO when the thrust levers reduced to idle and TR deployed to reverse Idle above 80 knots.
Starlionblue wrote:As mentioned above, controls are not "slammed", or "pulled". We use adequate force, which typically is not very much. Positive but delicate movements.
Side note: Airliners have thrust levers, not throttles.
Starlionblue wrote:Ianfromrussia, you seem very concerned about reaction times. In general terms, I would say that in an airliner it is typically better to take a bit longer making a decision than to rush things. An extra second or two, even in the case of a rejected takeoff decision, won't make a material difference.
Also, airliners are certified for controllability in abnormal situations. If a pilot of average skill cannot control the worst-case thrust asymmetry, the airliner would not be certified.
"
IanfromRussia wrote:Starlionblue wrote:Ianfromrussia, you seem very concerned about reaction times. In general terms, I would say that in an airliner it is typically better to take a bit longer making a decision than to rush things. An extra second or two, even in the case of a rejected takeoff decision, won't make a material difference.
Also, airliners are certified for controllability in abnormal situations. If a pilot of average skill cannot control the worst-case thrust asymmetry, the airliner would not be certified.
"
Do You mean that if the aircraft suddenly begins to veer off the centerline of a wet 140 ft wide runway and full rudder deflection appears just a bit short of stopping it doing so than an extra second or two before beginning to retard the thrust levers won't make a material difference?
I understand well that the aircraft are designed to be controllable in abnormal situations by an average pilot (with certain caveats). I may seem to be concerned with reaction times but not in the sense of believing that they are inadequate. I only try to learn what course of action is proper to fully exploit the capabilities of the aircraft and of an average pilot in certain scenarios. To put it plainly, I try to learn how an RTO (especially a most challenging case) looks from the cockpit.
113312 wrote:The actions depend upon the model of 737 you are operating. Newer ones have autobrakes and autospoilers. Both will activate when the trust levers are retarded in a rejected takeoff. However, it is the pilots responsibility to follow up that the spoilers did deploy and that the aircraft is decelerating. Autobrakes in RTO mode should provide optimum braking all the way to a full stop. However, it is human instinct to apply manual brakes which will kick off the autobrake function. In the old days on 707s and 727s without these features, the drill was: thrust levers idle, apply maximum brakes, speed brake lever extend. This is done without delay. Yes, there is a directional control element in the case of loss of thrust in an engine. But not all rejected takeoffs are from an engine failure. Even when there is asymmetric trust, maintaining directional control should be an instinctive reaction of the pilot with the rudder and should not result in significant deviation on the runway.
Boair wrote:I am not qualified on the 737 but did an MCC on the NG and from what I can remember we did in the sim:
As Starlionblue said, the captain will always have the hand on thrust levers until V1 and he will make the call and RTO, whether he is PF or PM. The procedure we used was (Captain):
1. Call "Reject", disengage autothrottle and apply maximum braking (manual or autobrake)
2. Close the thrust levers
3. Raise the speedbrakes lever
4. Maximum reverse thrust
All of this happen while the captain maintain the aircraft on the centerline.
Correct me if I'm wrong but we were told you first have to extend the speedbrakes and then only the reversers. Reason is that RTO distance are calculated only with speedbrakes so technically you only need them to stop, reversers are a "bonus" (and a useful one).
Starlionblue wrote:IanfromRussia wrote:Starlionblue wrote:Ianfromrussia, you seem very concerned about reaction times. In general terms, I would say that in an airliner it is typically better to take a bit longer making a decision than to rush things. An extra second or two, even in the case of a rejected takeoff decision, won't make a material difference.
Also, airliners are certified for controllability in abnormal situations. If a pilot of average skill cannot control the worst-case thrust asymmetry, the airliner would not be certified.
"
Do You mean that if the aircraft suddenly begins to veer off the centerline of a wet 140 ft wide runway and full rudder deflection appears just a bit short of stopping it doing so than an extra second or two before beginning to retard the thrust levers won't make a material difference?
I understand well that the aircraft are designed to be controllable in abnormal situations by an average pilot (with certain caveats). I may seem to be concerned with reaction times but not in the sense of believing that they are inadequate. I only try to learn what course of action is proper to fully exploit the capabilities of the aircraft and of an average pilot in certain scenarios. To put it plainly, I try to learn how an RTO (especially a most challenging case) looks from the cockpit.
As 113312 says above, if the aircraft starts to veer off the centreline the PF will correct almost without conscious thought. There is no delay. For retarding thrust, there's already a one-second reaction time buffer. Additionally, the calculations have a safety factor. So yes, if you delay pulling the thrust levers to idle for a couple seconds, you should still be able to stop.
IanfromRussia wrote:Boair wrote:I am not qualified on the 737 but did an MCC on the NG and from what I can remember we did in the sim:
As Starlionblue said, the captain will always have the hand on thrust levers until V1 and he will make the call and RTO, whether he is PF or PM. The procedure we used was (Captain):
1. Call "Reject", disengage autothrottle and apply maximum braking (manual or autobrake)
2. Close the thrust levers
3. Raise the speedbrakes lever
4. Maximum reverse thrust
All of this happen while the captain maintain the aircraft on the centerline.
Correct me if I'm wrong but we were told you first have to extend the speedbrakes and then only the reversers. Reason is that RTO distance are calculated only with speedbrakes so technically you only need them to stop, reversers are a "bonus" (and a useful one).
I need just a small clarification: can You confirm that "while the captain maintain the aircraft on the centerline" means "while the captain is taking actions to restore the original heading of the aircraft" and not "when the captain have restored the original heading of the aircraft and keeps it's course straight"?
IanfromRussia wrote:Starlionblue wrote:IanfromRussia wrote:
Do You mean that if the aircraft suddenly begins to veer off the centerline of a wet 140 ft wide runway and full rudder deflection appears just a bit short of stopping it doing so than an extra second or two before beginning to retard the thrust levers won't make a material difference?
I understand well that the aircraft are designed to be controllable in abnormal situations by an average pilot (with certain caveats). I may seem to be concerned with reaction times but not in the sense of believing that they are inadequate. I only try to learn what course of action is proper to fully exploit the capabilities of the aircraft and of an average pilot in certain scenarios. To put it plainly, I try to learn how an RTO (especially a most challenging case) looks from the cockpit.
As 113312 says above, if the aircraft starts to veer off the centreline the PF will correct almost without conscious thought. There is no delay. For retarding thrust, there's already a one-second reaction time buffer. Additionally, the calculations have a safety factor. So yes, if you delay pulling the thrust levers to idle for a couple seconds, you should still be able to stop.
So may it be stated that an average pilot have under such scenario a generous margin for error? Or, in other words, does this scenario require him to be careful of not falling below average?
bigb wrote:I can comment on the 737, but the 747 and I know 777. The speed brakes will auto deploy in the event of a RTO when the thrust levers reduced to idle and TR deployed to reverse Idle above 80 knots.
Starlionblue wrote:There is a margin for error like in all of aviation. With adequate training, a pilot who has passed the requisite checks to hold his/her position should be able to perform the tasks required.
I don't quite understand what you mean "careful of not falling below average"? We have to meet the required standard, both when on check, and when flying the line.
Starlionblue wrote:
the investigations of aviation accidents reveal that performance of some pilots during infrequent abnormal situations (sometimes rather mild ones) fell short of the training standards.
Can you give specific examples?
Starlionblue wrote:
Air France 447. Somewhat maybe. Fatigue definitely a factor. More importantly, at the time high altitude upsets like that were not really trained for like today. It is worth noting that there had been events of pitot icing previously, none of which resulted in an accident. Again, the events that ended well don't make the news.
Colgan 3407. IIRC fatigue was a factor. But again, what about all those approaches in poor conditions that did not end up in a crash.
USAF KC-135R, T/N 63-8877 (2013). Maybe. But yet again we must ask how many similar malfunctions did not lead to a crash.
VMCA787 wrote:I really can't add much more than what Starlionblue has added but I think you are overanalyzing the entire situation. First of all, given the number of movements during "normal" times and the relatively few incidents of RTO at high speed, I would say you are looking for a problem when no problem exists.
I am retired now, but I can count on one hand and have fingers left over the amount of RTOs I have experienced in over 50 years of flying in both military and airline operations. I have been a trainer, evaluator and the entire process should be "automatic" for the PF. During the takeoff briefing, one thing I always referred to was the concept both Boeing and Airbus use in aiding pilots with the entire decision to reject or continue. Studies and statistics show the crew is much better off by getting the aircraft in the air versus a high-speed RTO. Personally, unless I am convinced the aircraft will not get airborne, I will continue the takeoff. Nothing has to be done "in a hurry". That is probably the biggest error I see in the sim during training and checks.
I started my airline career with a US 121 carrier that had red tails on all their aircraft. They were overly conservative when it came to RTO and used "wet" V speeds to lower the V1 speed to get the pilots "go" oriented. And it worked.
BoeingGuy wrote:bigb wrote:I can comment on the 737, but the 747 and I know 777. The speed brakes will auto deploy in the event of a RTO when the thrust levers reduced to idle and TR deployed to reverse Idle above 80 knots.
The 787 and 777-9 are the only Boeing models in which the speedbrakes will deploy as part of the Autobrake RTO function. You don’t even have to deploy the Thrust Reversers. As soon as you retard the trust levers to idle, when above 85 knots and RTO autobrakes armed, the speedbrakes will deploy.
All other Boeing models have an interlock such that when the thrust reverser handles are raised, the speedbrakes will also deploy. Several other posters have mentioned this.
The reason Boeing has recommended manually deploying speedbrakes during an RTO, even with the T/R interlock, is because the reliability numbers of that interlock function working didn’t meet the required reliability for the hazard level of the speedbrakes not deploying during an RTO. Last I heard, Boeing was re-evaluating that guidance, but not sure what became of it.
Woodreau wrote:You should find a simulator and see if you can get to experience a rejected take off or perform one yourself... It's not likely in the US, but it seems there are enough aviation enthusiasts who are able to get simulator time in Europe.
Boair wrote:I am not qualified on the 737 but did an MCC on the NG and from what I can remember we did in the sim:
As Starlionblue said, the captain will always have the hand on thrust levers until V1 and he will make the call and RTO, whether he is PF or PM. The procedure we used was (Captain):
1. Call "Reject", disengage autothrottle and apply maximum braking (manual or autobrake)
2. Close the thrust levers
3. Raise the speedbrakes lever
4. Maximum reverse thrust
All of this happen while the captain maintain the aircraft on the centerline.
Correct me if I'm wrong but we were told you first have to extend the speedbrakes and then only the reversers. Reason is that RTO distance are calculated only with speedbrakes so technically you only need them to stop, reversers are a "bonus" (and a useful one).
Braking was up to you but you have to check AUTO BRAKE DISARM light first. If the light was on or you preferred manual braking, you apply manual braking.
FO in the meantime cross-check the captain's actions (AUTO BRAKE DISARM light, speedbrakes, reversers...)
AABusDrvr wrote:Boair wrote:I am not qualified on the 737 but did an MCC on the NG and from what I can remember we did in the sim:
As Starlionblue said, the captain will always have the hand on thrust levers until V1 and he will make the call and RTO, whether he is PF or PM. The procedure we used was (Captain):
1. Call "Reject", disengage autothrottle and apply maximum braking (manual or autobrake)
2. Close the thrust levers
3. Raise the speedbrakes lever
4. Maximum reverse thrust
All of this happen while the captain maintain the aircraft on the centerline.
Correct me if I'm wrong but we were told you first have to extend the speedbrakes and then only the reversers. Reason is that RTO distance are calculated only with speedbrakes so technically you only need them to stop, reversers are a "bonus" (and a useful one).
Braking was up to you but you have to check AUTO BRAKE DISARM light first. If the light was on or you preferred manual braking, you apply manual braking.
FO in the meantime cross-check the captain's actions (AUTO BRAKE DISARM light, speedbrakes, reversers...)
The biggest reason you want to get the speed brakes deployed, is to get the "weight" of the airplane off the wings, and on to the wheels. The brakes will do a much better job of stopping the airplane, than the reversers will.
Also, at my airline at least, it's policy on the 73 not to use manual braking during an RTO. If you disengage the auto brakes before the airplane is stopped, that will earn you at a minimum a debrief, and most likely you will be doing it over again before your sim session is over. The reasoning there is RTO brakes provide the maximum possible stopping effort, much better than maximum manual braking.