Thrust selection after engine failure/ fire on takeoff

[John Citizen]

As I understand there is no requirement to select max. thrust following an engine failure on takeoff using reduced/flex thrust.

However I have come across many different opinions :
- some say always immediately select max. thrust to improve climb performance
- some say leave the thrust as it is, to avoid destabilising the aircraft, and then perhaps add aditional thrust (if required) once the autopilot is on

I suppose these are all acceptable techniques, however some also say :
- don't ever increase thrust if an engine fire (don't add fuel to the fire)
whilst others say
- it's ok to increase thrust (on both engines) even if an engine fire

I have looked through the manuals and can not find any specific instruction regarding the selection of max. thrust following an engine fire.

With so many opinions and techniques out there, it gets a bit confusing what to do. Everytime I am in the sim. I come across different techniques and I am always having to retrain myself. But seems like no matter what I do, some checkie will come up with a different technique yet again. Just can't win sometimes

I am interested in hearing other peoples opinions.

[punk666]

The assume/flex take off takes into consideration of an engine failure and its climb performance.

So there is no need to add additional thrust in the event of an engine failure after takeoff unless you really need!!

In a turbo prob maybe this might be the case because the dead engine will produce alot of drag and props are not as powerful as a turbine engine.

But from a jet point of view with an engine failue you rotate at a slower rate and pitch attitude usually around 12.5 degrees (B737).

Assuming your maintaining runway heading, at your designated accel altitude you select flaps up speed and accelerate selecting the flaps up on schedule. Once the flaps are up and your still climbing you would ask for level change (B737) and ask for max continuous thrust.

Thats the way I have been taught, some suggest getting the autopilot in straight away to reduce workload, some say dont bother till level flight so you can trim the aircraft easily instead if doing it during a climb and constantly re-trimming as you speed up.

[Spendid Cruiser]

Here is the 737 FCTM extract:

Engine Failure During a Reduced Thrust (ATM) Takeoff

Since the reduced thrust (ATM) takeoff must still comply with all regulatory takeoff performance requirements, it is not necessary to increase thrust beyond the reduced level on the operating engine in the event of an engine failure. However, if more thrust is needed during an ATM takeoff, thrust on the operating engine may be increased to full rated takeoff thrust by manually advancing the thrust lever. This is because the takeoff speeds consider VMCG and VMCA at the full rated takeoff thrust.

Increasing thrust on the operating engine to full rated takeoff thrust provides additional performance margin. This additional performance margin is not a requirement for the reduced thrust takeoff and its use is at the discretion of the flight crew

Messing around with thrust is an additional task in a demanding and critical
situation and yet adding thrust would increase your rate of terrain separation.

My view is that one should dispense with rigid solutions and simply remain situationally aware and assess the risks, remain flexible and attempt to go with the least risk option by balancing sensible precautions with workload according to the conditions.

Sometimes you just have to agree to disagree. Personally, I endeavour not to be railroaded by examiners, instructors and Captains (or any other more experience pilot). I don't know what your experience level is, but I found that the confidence required to politely push back on advice that lacks merit, especially during a recurrent sim, takes time to develop.

[john_tullamarine]

Summary of some points to keep in mind -

(a) derate/flex meet the certification requirements - then why do we accept going at MTOW in critical conditions ? Double standard ? The days of pilots doing things to make life more comfortable for pilots during flight have long gone to make way for LoCo competition.

(b) derate is the limit so there is no increase beyond that during the takeoff phase

(c) flex can be run up to rated/derated as applicable

(d) if (c) is applied, be VERY wary of dynamic effects on thrust and subsequent yawing moments. I was involved in the investigation of one fatal where this was very likely a contributing factor.

(e) if (c) is applied to a turboprop, be careful of drag effects due to prop blade gyrations - similar concern to doing asy work by snap closure of the throttle - one can get significant drag on the "failed" prop

... as GF observes in a parallel thread, do it slowly ...

[John Citizen]

extract from the Airbus Flight Crew Training manual :

THRUST CONSIDERATIONS
Consider the use of TOGA thrust, keeping in mind the following:
• For a FLEX takeoff, selecting the operating engine to TOGA provides additional performance margin but is not a requirement of the reduced thrust takeoff certification. The application of TOGA will very quickly supply a large thrust increase but this comes with a significant increase in yawing moment and an increased pitch rate. The selection of TOGA restores thrust margins but it may be at the expense of increased workload in aircraft handling.

[aterpster]

John Tullamarine:

(a) derate/flex meet the certification requirements - then why do we accept going at MTOW in critical conditions ? Double standard ? The days of pilots doing things to make life more comfortable for pilots during flight have long gone to make way for LoCo competition.

True, but a lot of rote there.

If departing an Aspen or an Eagle, just forget derate/flex thrust completely. The price of being wrong if nothing happens is very low. The price of being wrong if you select derate/flex thrust at such locations, particularly during unstable atmospherhic conditions may carry a very high price for being wrong.

[390cruise]

Airmanship???

Guys

Most pilots will not experience an engine failure during a career of thirty or fourty years.So are we saying that as we climb away after the event we are happy with less than 50% thrust even though we have increased drag from control deflections (and perhaps damage) ? Aimanship??

Reduced thrust is based on takeoff mass as shown on the load sheet.Load sheets are based on standard masses of humans and bags. During my B737 and A320 years I think the actual aircraft mass was often two or three tonnes higher than shown.

The manuals, company, flight crew training, etc etc vary and change.....so what do the people who build the aircraft think?

The Airbus 'Approved flight manual' (remember when these were carried onboard?) has limitations for use of reduced thrust. One of these is........when an engine fails during a reduced thrust departure TOGA shall be selected on the operating engine.

So engine failure, smooth selection of TOGA, trim then autopilot.

390

[SNS3Guppy]

However I have come across many different opinions :
- some say always immediately select max. thrust to improve climb performance
- some say leave the thrust as it is, to avoid destabilising the aircraft, and then perhaps add aditional thrust (if required) once the autopilot is on

I suppose these are all acceptable techniques, however some also say :
- don't ever increase thrust if an engine fire (don't add fuel to the fire)
whilst others say
- it's ok to increase thrust (on both engines) even if an engine fire

John, you may be confusing different events or scenarios.

Given a power loss, engine fire, failure, or other problem after V1, in which the airplane is still going flying (given that insufficient room remains to reject the takeoff), one is going to continue using the thrust with which the takeoff has been planned, and briefed.

A reduced thrust takeoff, as others have noted, takes into account performance with an engine loss. The speeds that are calculated are crafted with this in mind, and the performance that remains with an engine lost. The rejection numbers are applied accordingly. Add thrust, and one may very well have a dangerous condition, especially at low speeds during the initial takeoff. The best course of action is to leave everything alone, climb to a minimum safe height, begin to clean up...and during that time one can apply maximum continuous thrust, run checklists, etc.

If one has an engine fire on takeoff without any thrust loss, why on earth would one want to increase thrust or need to do so? That makes no sense.

If an engine fire occurs during the takeoff at a point where stopping is no longer an option, then the same procedure occurs. Climb, get to a safe altitude to configure and run checklists, then handle the emergency. Unless actual control of the aircraft is threatened, then one has a singular priority during the takeoff; maintain control of the airplane, and fly it to a safe altitude. Only after that has been accomplished does one begin changing airplane configuration, power settings, or addressing the emergency.

As always, fly the airplane first.

[390cruise]

50% agree

SNS3Guppy

'one is going to continue using the thrust with which takeoff has been planned, and briefed.'

Indeed......my brief will include 'in the event of an engine failure after V1 I will select TOGA'.

I accept your comment about selection of high power on one engine at low speed but have not found it to be limiting.

The engine fire case 100% agree with you.

We should all remember that it is very important to comply with the approved standard operating procedures of the aircraft operator.

390

[John Citizen]

John, you may be confusing different events or scenarios

I am talking about engine failure after V1
- with/without a fire

[SNS3Guppy]

I know you are, John, but your responses indicate some confusion all the same.

A takeoff based on reduced thrust is predicated on keeping that reduced thrust setting; the performance, takeoff distance, and climb performance that are predicted as part of the pre-takeoff calculations are based on continuing the takeoff with reduced thrust.

Certainly if one finds one's self in a situation requiring greater thrust, it may be increased. However, one may also find one's self in a position of having insufficient control authority if one has used the performance numbers for the reduced thrust takeoff.

Remember that increasing thrust asymmetrically increases yawing moment. One needs a certain amount of rudder (and aileron and spoiler deflection in many cases) to counter this increase. At low speeds, pushing power on the good engine may counterproductive. The takeoff has been planned to safely continue, and meet all the applicable climb requirements, with the existing reduced thrust.

Whether one is on fire or not, or whether one has a fire indication, doesn't change the basic requirement to fly the airplane. Unless the procedure for your particular airplane calls for increasing thrust early in the takeoff, then one should not do so. Whether the airplane is on fire or not doesn't change that requirement: fly the airplane to a safe altitude, clean it up, and handle the abnormality or emergency.

If a fire warning occurs, silence the warning, continue, clean up, and execute the memory items or checklist items as appropriate. The rules don't change: Aviate (fly the airplane), Navigate (direct the airplane), and Communicate (talk about the airplane). Do that.

If you're on fire, remaining airborne for an extended period isn't in your best interest. Fly the airplane, first and foremost. If you've lost thrust and have an engine-out (and burning), then you've got the same problem initially as with a simple engine failure. You're going to fly the airplane to a safe altitude, begin speeding up and cleaning up, address the problem, fly the turn procedure or navigate otherwise as required, and notify ATC or other resources as necessary. If you're on fire, you'lll be likely returning to the airport very shortly. In order to do that, you need to fly the airplane.

Your question asks about an engine fire, and increasing thrust on the burning engine. Clearly, if one isn't going to increase thrust with an engine failure, then one isn't going to increase thrust with an engine fire.

Our procedure in the event of a power loss during takeoff, after V1, involves climbing to a pre-determined minimum level-off altitude, and stopping the climb. We begin cleaning up the airplane, and with the initial increment of flap retraction, we set max continuous thrust. We then clean up the airplane, address the problem, run the appropriate checklists, and in the meanwhile navigate as necessary while requesting help.

What we don't do is increase thrust. Reduced trust takeoffs are constructed with a power loss in mind. It's already taken into account insofar as runway takeoff distance required, and the climb performance once airborne. It's also predicated on other factors, each of which combine to either make it safe to do the takeoff with an engine failure at or after V1, or not. If not, then it's not a reduced thrust takeoff. If it is safe, then a thrust increase isn't required.

If you happen to fly an aircraft that uses a different protocol, then follow that.

[Exaviator]

Anyone who has been through the Airbus training school at Toulouse will be familiar with two standard answers from the instructors there. The first being,"It is automatic". The second being, "You are the captain, it is up to you".

The latter is applicable in this discussion. Performance calculations dictate that you do not need to apply extra thrust following an engine failure, BUT hey if you need it, TAKE IT, all the way to the firewall if necessary.

That's why you get paid the big bucks - to make decisions and take responsibility for them. Or at least you did in my day, has any thing changed???

[Escape Path]

If one has an engine fire on takeoff without any thrust loss, why on earth would one want to increase thrust or need to do so? That makes no sense.

As one wouldn't immediately reduce power on the smoking engine either despite the fire bell. It is giving some thrust output, use it in the initial climb. Once you are a bit a away from the tree tops and with the gear and flaps up, then you can shut down the engine completely.

Or so I was taught...

Escape Path

[stilton]

Unless performance is not working out as planned after an engine failure I would always leave the thrust alone.



On the 757 in particular there's a fairly healthy yaw into the failed engine, once youv'e got that sorted out why b****r around with your controllability again by adding power.



More Importantly, you only have one engine left and you might want to take as good care of it as you can until you have landed

[firefish]

Having not flown any aircraft approved for any kind of derated thrust during take off I can still agree on that it might be wise not to change the configuration of the aircraft as well as treating the remaining engine with a little extra care.

But on the other hand the engines are certified and approved for running at t/o thrust for a certain time (in my case 10 mins when single engine - this might be the common rule) meaning that there really shouldn't be anything to worry about. In addition to this one must also consider the reason for say an engine failure and depending on the conclusion drawn it may very well be a good idea to set max thrust on the remaining engine in order to get as far from the ground as possible before the it quits too (fuel filter by pass on the running engine - contaminated fuel).

What it all boils down to - as usual - is that it is up to the captain/crew depending on the specific conditions for every specific scenario. It is impossible to say that either of the procedures is always right (or always wrong). I can recall a number of accidents where aircraft have been lost, both due to the crew not selecting max thrust when needed to and in some cases when they have killed the remaining engine by doing it.

As always, fly the aircraft and don't just do stuff without thinking first. Even though a V1 cut is about as bad as it can get it's what we all have been trained for and what the airplane has been built to do (with some safety margins too) and it's not about split second decisions. I absolutely agree on that you should engage a/p asap, if the conditions permit, in order to free capacity so that both crew members can start to evaluate the situation properly.

[john_tullamarine]

If departing an Aspen or an Eagle, just forget derate/flex thrust completely

Absolutely the case that some circumstances dictate the use of rated thrust. As a wise checkie once counselled me "Lad, read the Ops Manual with a modicum of commonsense"

Likewise I have never inclined to the view that one should make a non-limiting takeoff into one by, for instance, flexing to the limit. For that reason I always liked Wal Stack's approach when he introduced flex to Qantas - leave a pad for mum and the kids in the calculations .. that also made the new procedure a lot easier to market to flightcrews.

I have no inherent problem with running up the operating lever a bit. Only three caveats -

(a) know where you are with respect to Vmc

(b) do it ever so measured and steadily

(c) have some practice exposure to the exercise in the sim prior to chancing it in anger ....

[FullWings]

As always, fly the aircraft and don't just do stuff without thinking first.

Absolutely. There are not that many of what some call "time critical scenarios" and only a handful of those need *immediate* pilot input, such as RTOs and hard GPWS warnings.

On my first jet (737-200), the company SOP was TOGA thrust on the live engine after engine failure. We then started operating FMC-equipped variants (300/400, etc.) and had done so for quite a while when someone new to the fleet pointed out that this was not such a good idea as at high derates and low weights, as you could end up very close to, even possibly at or below Vmca, due to the way we calculated the speeds. Cue overnight new SOPs.

Engine "fire" warnings: all they tell you is that somewhere in the nacelle, the temperature is high enough to have triggered the detection system (or there's a fault in the wiring). It doesn't often mean that flames are gushing from every orifice and the engine and/or wing are about to burn off, although this is a possibility. Unthinking and/or panicky reactions to warnings can often put the flight in substantially greater jeopardy than a more considered approach...

[MD83FO]

one of the most compelling reasons not to increase thrust that I learned from early jet aircraft literature, is that the more thrust you demand from an engine, the higher the chances of it failing.

is this not relevant for the newer engines?

[de facto]

I fully agree with JhonT and SN3 Guppy, just Guppy, in 737 we clean up first before selecting MCT,then keep that thrust setting until level off at a safe altitude.

With derate,unless some really feels wrong,leave the remaining thrust alone.
If you need this extra thrust,get rid of the ASSUME using FMC N1 but NO TOGA or fire wall

[390cruise]

35'

Guys

We don't all agree but the discussion is healthy so we can all learn.

Am I a little out of date if I recall that in the V1 continue case we will clear the end (screen height) by 35' or more if the all factors are correct?

I strongly believe that most Airline jets depart at up to 5% above the takeoff mass shown on the load sheet.

The culture of 'save the good engine' dates from the piston era.

Engine failure are rare, will really notice if 'something feels wrong' to increase power? when so much is already wrong.

Also at high masses Vmca is not a problem, while at low masses thrust is not such a problem and anyway speed tends to run away!!!

Yes I agree with John respect Vmc, thrust up with care and practise the whole thing in the sim.

390