engine out acceleration vs recall items B737 CL
 

Hi folks.
My airline has just raised the minimum altitude at which you can initiate recall items from 400 ft to 1000 ft AFL. This means that if you have an engine fire or severe damage situation you would start executing the recall items at the accel height...personally I would do the recall items first, and then accelerate, that probably means accelerating a few hundred feet higher than 1000 ft, but guarantees no mixing of procedures and hand crossing here and there...what do you guys have to say?
Thanks,
SW.
PS: this assumes no particular engine out drill...

Yep , non normal procedures first then tidy up(clean up). The 400 foot limit is to assure second stage climb performance and continuing that to 1000 is conservative but you are still meeting the second stage climb performance of 2.4%.You then want to close it down or whatever the non normal dictates. We don't do anything below 400 and then the first thing the pilot flying does is to ask the support to "identify the problem". You may like to do this at 400 feet and then prethink your non normal checklist to then commence at 1000.

sudden winds,

Whats the logic behind increasing the SE accel ht from 400 to 1000 feet? How does the resulting weight loss impact your operation?

Mutt

Hi everybody

Unless ground contact is imminent and the aircraft is not fully under control..i don't see any reason why the boxed drill items should be delayed to 1000 AFL
That's an extra 15-20 seconds with the engine burning:confused:

thanks folks...well I don´t know why they did that...all I needed was some help regarding that matter...by raising the accel ht we get to a point where we can do two things...and some may be confused as to which one to do first..I personally have no doubts, but needed your opinion. Thank you all. Every time I post a question here I get very good answers within minutes ! THANK YOU GUYS !!!
SW.

assuming the engine is in fire, in the old propliners you could take it down to a lower altitude at a angle and force air into the engine to extingush it I think? (or is that a myth?) could that be done with a jet engine fired aircraft?

There seems to be a little bit of confusion creeping in here and I hope that I don't add to it!
IIRC the B737 manuals use the 400' height as the trigger to confirm the roll mode (HDG select) and to confirm the nature of the problem. If the problem is a problem that requires a recall drill then 400' is the earliest height that you should initiate any drills provided the aircraft is under control. The acceleration height remains at 800'/1000' AGL, or as specified by your take-off analysis procedure.
If at the 400' height the problem is confirmed as say an engine rundown then the drill is not a recall drill and can be left to a later stage.
Sudden winds without knowing the background as to why your operation has begun advocating this change in your procedure, I can only assume that like a couple of operators that I know of, they have decided that it is a reasonable compromise between operating the aeroplane safely and carrying out necessary non-normal drills. 400' is awfully close to the ground it is better to ensure the aeroplane is under control before any crew member begins carrying out checks.
A couple of points to consider. The Boeing manuals tell you that there are two instances that require immediate corrective action. The GPWS telling you you are about to hit the ground, and a stall. In almost every other situation you do have time.
In the case of an engine fire, severe damage, or seperation, just stop and think about these for a moment. Yes they are all recall drills, but even if the engine is on fire the chances are it is still producing plenty of thrust, so use it. A couple more seconds to let it get you up to the 1000' could be valuable and is unlikely to do much more damage to the engine itself. Also remember engines are supposed to be hot, the whole engine and pylon is designed to withstand heat, and the flames (if there are any) are being blown clear of the fuselage and tailplane. Over the years I have heard a number of stories of engines burning away on the wing until they fall off, and the aeroplane continued on safely enough. If you delay the drill for severe damage so what. The thing is already damaged, another few seconds will not make much difference, use those seconds to get to a safe altitude. Seperation, well the engine has fallen off anyway, youre just going to be going through the tidying up process, and without the weight of the engine it should be climbing well enough.

Capt Chambo,
I fully agree with delaying the recall items. The only downside is it may cause confusion as to priority at HA. "Should I do the flaps first or the recall?"

If the recall items are left too long will you bust the TO thrust time limit?
If the accel is left too long will you bust the TO thrust time limit?

I personally don't give a rats about the time limits but I could never advocate that principle to anyone, so the SOP must make it clear as to the priority at HA.

Mutt,
I think that we may have had a minor discussion upon the weight impact of a nominally increased acceleration height Vs MAA a few thousand posts ago.
We use a minimum acceleration height of 1000 feet, irrespective of a lower MAA. There's no weight penalty as the calculation is based upon the required 1st/2nd obstacle clearance to the "real" MAA (e.g. 500 feet), and NOT upon the performance degradation suffered by using an increased acceleration altitude. If, for example, MAA was 500 feet with a 2nd segment gradient of 2.0% required to MAA, the degradation between 500 and 1000 feet is minor, usually of the order of -0.1% or so, but of no consequence in this phase as the obstacle has already been cleared.:ok:
In earlier times the philosophy DID consider the increased Pressure Height to the artificially increased MAA, but on 95% of occasions no weight penalty resulted as it usually meant using a slightly lower Assumed/Flex temperature. On the other 5% of occasions, weight did suffer. That particular philosophy is no longer used.
Regards,
Old Smokey

.. other than when WAT-limited .. when the delta needs to be included.

Old_smokey,

Our standard policy is 800 feet, our Brazilian jungle jet took a payload hit at certain airports to achieve this height, hence my question, did the 737 operator analyze the payload impact, if any, caused by this increase.

Mutt

... if I were a betting man ... my money would be on "not". Common pilot mistake to look at the terrain without consideration to the climb number requirements ...

Interesting personal observation although I very much doubt if this advice will be found in any manufacturer's manual if only because of litigation reasons.

Personally, any fire in an aeroplane that I am flying either as a pilot in command or as a passenger, would scare me stiff. I recall some aircraft experiencing an engine fire have about two minutes before the main spar burns through due to the blow-torch nature of the flame-front and then it is curtains for everyone.

It begs the question why deliberately let an engine burn following an engine fire simply to hang on to more thrust when if the runway analyses is valid the aircraft has more than adequate performance to meet certification figures.

You may never know how bad a fire is until it is too late to fix. Your company policy of delaying action until third segment height is attained sounds like the work of a new broom check pilot sweeping clean without regard to airmanship. Which reminds me. I understand the term "Airmanship" has been discarded in new publications in favour of the rather grand and verbose term "Threat and Error Management."

Airmanship will still do me, thank you very much.

Jeez Centaurus, just when us Perfophiles were getting into full swing in changeing the direction of the thread, you spoil it all by reverting to topic!:*

Shame on you!:E

Just for the record, I agree entirely with your post:D

Regards,

Old Smokey

Thanks, Old Smokey. If I can borrow the words of Yogi Bear the hero of many a wonderful cartoon - "If there is one thing I love - it is constructive criticism!":D

Question: Is there a historical reason why recall items are delayed to >400AGL? My company manuals suggest that 400' is not a minimum but a typical height at which to initiate. I dont see what possible reason there is to delay the fire fighting if the aircraft is under control and not in imminent danger of flying into the ground...The sooner it is dealt with the sooner (wx and terrain permitting of course) you can point the thing in the other direction and recover your ailing ship surely???

Underreadeast.
Agree entirely. In my experience there is a tendency for some crews to be ultra-conservative when it comes to judging when it is "safe" to take the first action to deal with an engine fire after lift off. Obviously, if for some reason or other the pilot is experiencing significant difficulty in controlling the aircraft dangerously close to the ground, then the pilot is faced with the choice of two evils; get the aircraft straight and climbing or fight the fire. Naturally the answer must be to regain control of the aircraft.

But to deliberately delay the fire fighting recalls until an arbitary height above the ground - even though the aircraft is nicely under control already - indicates a touching faith in the design capability of the aircraft to withstand the hottest of fires. Boeing for example use the phrase "Acccomplish the appropriate recall actions....at a safe altitude (typically 400 feet AGL or above). I see no reason why recall actions should not be started asap after the first fire warning indication. There is little point in stating the obvious that the aircraft must first be kept under control. But to deliberately delay fire fighting action in order to meet what may be an ill-researched and possibly fatally flawed local SOP ( in this case raising the min height for recall actions to 1000 ft AGL) - is an unneccessarily risky action.

It is an interesting qustion.

The Embraer 170/175/190/195 standard procedures (the manufacturers procedures) have you do the recalls after the aircraft is clean.

It means that the fire is burning for quite a long time - but seems to work

As far as I am aware Contintental dont have engine fire as a recall item on the B737.

There is much to be said for shifting the running of checklists to a higher altitude, particularly given the real rate of engine fires in operational service.

Funnily enough we practice engine failures etc in the sim with monotonous regularity but we pay very little attention to the meaning of the RTOW/runway analysis charts.

I often see people compromise line up allowances on relatively short runways with not the slightest concern about what will happen on a high speed reject - this is particularly relevant on runways where the LANDING threshold is displaced but the start of takeoff is not (YSSY 16L for instance).

I believe the need to react to fires etc at a low level is a hangover from days gone by and may be worth revisiting to see exactly how relevant it is to todays aeroplanes (bit like limited panel)

At my 'house' we did away with almost all memory items including the engine fire/failure checklist. Fly the airplane first...
In the case of an engine fire on takeoff, we climbed to 1000ft, cleaned up, read the bold print challenge and response items and then once the engine was shut down, we engaged the autopilot, the F/O monitored the autopilot and the capt ran the checklists. This worked extremely well as the Capt was now free to use all his/her braincells/experience making decisions, the F/O was making inputs to the A/P and the A/P was handling the flying. The workload division was excellent.
Also, by removing the memory items, it slowed things down a bit when the adrenaline was flowing and the chance of putting the #1 throttle in cut-off and pulling the #2 fire handle was possible.
As for time limits and thrust limits, those are for *normal* ops and an engine fire at my old house was never considered a normal event so we didn't worry about those limits.
This tendency to confuse normal limits with emergencies is still around. A while back when I typed on the CitationJet, the training company wanted me to make sure I didn't exceed normal takeoff thrust limits in the stall recovery. Since I didn't think stalls were normal events and since Air Florida proved that most fly as they are trained... I suggested we do away with the limits. It caused some blank looks.

I think the attitude of do-it-FAST is a hang over from the old big recips where when they started belching and barking, it wasn't long before they started eating themselves and everything around including the wing. Not so with jets IMO...

Consider the following. At 400 ft (or lower) the PNF starts shutting down things. Unfortunately, he gets the wrong things shut down - despite the requirement for confirmation from the PF.

In over 20 yrs of instruction in sim and aircraft I have seen pilots rush into a procedure too soon and often get it wrong. In the debrief, he usually said "but I'd never do that in the aeroplane." To which the response always was "you've just done it".

All the various accel altitudes and SOP re where the recall items should be done are a compromise between getting the engine shut down, fire extinguished etc on the one hand and ensuring the a/c is flown accurately to a safe height above ground. Various airlines/manufacturers will adopt various altitudes/SOPs for these scenarios usually depending on their previous experience (or that of the Chief Pilot). Better follow your company's SOP in all cases unless they are clearly seen not to be adequate for the situation. After all they have been thought out in the cold light of day - not when you are at 200ft with an engine on fire.

For what it's worth, having seen hundreds (yes) of pilots rush into checklist items in the sim only to get them wrong. I'm firmly of the opinion that the best thing to do at very low level is DO NOTHING. PF flies the a/c and PNF monitors his flying. If you don't do that you'll burn the whole a/c not just the engine. It sounds obvious but most sim instructors will agree that one of the biggest problems is that of pilots rushing into drills and nobody is "minding the shop".

My personal view is that you should begin the drills for an engine fire or severe damage asap after 400 ft, WHILST ENSURING THE PF IS FLYING THE A/C ACCURATELY i.e it doesn't stop you from performing your prime role to monitor the other pilot's flying especially at low level and with a problem. Many airlines have changed the title PNF to PM - pilot monitoring - to emphasise this very fact. In any case, follow your company's SOPs and if you disagree with them make your objections known and perhaps they will think again if you have a strong enough case.

All other non-critical items should be held until the a/c has been cleaned up and it being flown to a safe altitude where both pilots can fully monitor what each is doing. Use the automatics to the max extent possible.