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

B737NG engine fire just below V1

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

B737NG engine fire just below V1

Old 17th Jun 2007, 05:55
  #21 (permalink)  
Join Date: May 1999
Location: Quite near 'An aerodrome somewhere in England'
Posts: 25,433
Please tell me which airlines those of you who won't abort for an engine fire warning at V1 fly for?

So that I can avoid them!
BEagle is offline  
Old 17th Jun 2007, 09:48
  #22 (permalink)  
Join Date: Jul 2000
Location: Thailand
Posts: 940
Beagle, you won't be able to fly again then. All airlines follow the procedure that if the engine fire/failure occurs at V1 then the take-off will be continued. Find me an airline that doesn't teach that and I won't fly with them!
rubik101 is offline  
Old 17th Jun 2007, 10:04
  #23 (permalink)  
Join Date: May 1999
Location: Quite near 'An aerodrome somewhere in England'
Posts: 25,433
All right then, before the V1 call.

It should always be possible to reject a take-off before V1 - that's what it means.

But it requires prompt performance from a practised crew; and the closer you get to V1, the more important this becomes.

But rarely is V1 so limiting that an abort precisely at V1 will not allow the aeroplane to be brought to a halt on the RW/stopway remaining.

I must have initiated hundreds of fires/failures at V1 over the years (in the simulator, I hasten to add). Rarely did anyone screw up an abort disastrously - but they did have the luxury of at least 9 x 3 hour simulator sessions per year. Something which I doubt airline beancounters would ever allow these days.
BEagle is offline  
Old 17th Jun 2007, 12:30
  #24 (permalink)  
Join Date: Apr 2001
Location: various places .....
Posts: 6,513
Putting the desirability of procedural standardisation to one side .. one of PPRuNe's values lies in providing a forum for discussion ... it still depends on the circumstances.

It should always be possible to reject a take-off before V1 - that's what it means.

Depends on the certification basis for the Type/Model .. in particular, two engines operating vice one.

Depends on the environmental circumstances .. runway surface contamination, over run environment, and how limiting is the accel stop case (the 2 second pad may not apply for many of our older aircraft)

The correct answer is that as long as you can take the first action to abandon the take-off by V1

No decision to consider here .. in a limiting case, once you have initiated the stop, particularly when the brakes come into play, there is no changing your mind ...

Overall, we go with standardisation for all the usual reasons .. but it is appropriate that we are aware that there are sets of antipathetic circumstances which are going to bring us unstuck if we follow the "standard" gameplan.
john_tullamarine is offline  
Old 17th Jun 2007, 13:41
  #25 (permalink)  
Join Date: Jun 2000
Location: Australia
Posts: 3,865
This is one of those conundrums where you might very well be "damned if you do and damned if you don't" . The correct answer is determined retrospectively by the outcome on the day .... and the Judge at the Enquiry ... if the outcome was less than fortunate on the day ..
A well considered, thought provoking, reply, JT. Nicely put.
Interesting statements noted that structural failure due fire damage could occur with 3-4 minutes. Maybe so, although others may have contrary opinions on the safe time left.
Yet, in the many PPRuNe posts on engine fires (theory of) observed over several years, the majority of correspondents felt there was no great hurry to close down the engine and firing the bottles. These opinions appear to be based on the theory that the engine will probably fall off the wing before causing fatal structural damage. Again all theory and precious few facts.
In the simulator we see time and again, pilots who delay actioning the fire bottles until at least a minute - and worst case two minutes, after the initial fire warning. "There is no urgency" is their mantra - the excuse being the aircraft must be got under control before the crew look around the cockpit to see what the red lights are all about.
If an engine has failed after V1, (whether simultaneously with a fire warning or not) I would have thought the pilot would have not only immediately had the aircraft under control but the crew would have taken action to shut down the engine and fire a bottle if appropriate. This is notwithstanding the oft mentioned minimum height of 400 ft being attained before the first action is started.
Complacency in handling an engine fire can be potentially dangerous. There is no authorative guide that explains how much time is available before structural failure occurs following an un-actioned engine fire.
That being the case, a crew cannot afford to take the risk that all will be well and the bottles can be actioned at pilots leisure. The 3-4 minutes of safe flight available mentioned in these posts, suggests that others think along similar lines?

Last edited by Centaurus; 17th Jun 2007 at 13:51.
Centaurus is offline  
Old 17th Jun 2007, 14:16
  #26 (permalink)  
Join Date: Nov 2003
Location: Over the Moon
Posts: 712
In my previous life we relied heavily on rear crew to tell us what was going on. In two cases the info they gave enabled the flight deck to make the decisions required to save all their lives. Nimrod with bomb bay fire at St Mawgan when they turned back to land on reciprical and Nimrod ditching in the Moray Firth after an uncontained fire started by an errant air valve/starter motor. In both cases it was later assessed that the aircraft had been very close to structural failure within minutes. Tragicaly in Afganistan the crew were unable to get on the ground before that structural failure occurred.

I accept that pod mounted engines are different as they should fall off but it does illustrate how deadly an uncontained airborne fire can be and how little time may be available to you. For all you know the fire may be due a fuel leak ala Concorde which will rapidly spread so best to stop in my view. Would I stop at V1/rotate on a long non FLL runway with 7000' left ?, in the sim no, in the aircraft with a fire warning then yes I would and take my bollocking.

As an aside I always make a point in the sim of getting the senior cabin crew to do a visual on any engine that indicates the fire has been extinguished as fire wires have been known to burn through and thus indicate all is well (ish) and previous indicates that info from the rear may well be crucial.
Ashling is online now  
Old 17th Jun 2007, 14:48
  #27 (permalink)  
Join Date: Mar 2002
Location: Florida
Posts: 5,116
The data is clear that far more accidents have occurred for aborting takeoffs between 100 kts and rotation then for continuing a takeoff after a fire warning. In tne analysis of engine fires (the cause of the firebell) there is little data that shows that the fire will progress beyond the engine pod itself for several minutes while airborne.

The greatest majority of serious engine fires which have disabled the aircraft, have been associated with ruptured fuel tanks and ground pool fires after the aircraft has been brought to a stop. So yes my arguments are based on statistics and not one-offs like a Concorde

In the case of the high workload decision making in a takeoff environment, the addition of a firebell ringing at the point where intent of go-no-go and rudder control are paramont is an additional pucker factor that may impact on the more paramont decsisions of the bolded above. Hence, I believe that some aircraft automatically inhibit the firebell in this time frame. (perhaps a check with your aircraft manual might confirm this).
lomapaseo is offline  
Old 17th Jun 2007, 15:32
  #28 (permalink)  
Join Date: Jan 1999
Location: hongkong
Posts: 187
A fascinating discussion with some interesting views for and against. As stated before my money is on stopping but I still want data!

As a friend of mine often says "without data you've only got opinions".

I have looked and searched many places but there is no hard data that I can find of engine fires in podded engines causing quick structural failure. Similarly how many engines go 'bang' at V1 (or close to it)?

That said you'd look pretty stupid carrying an engine fire into the air when using a take-off alternate. Imagine flying for an hour with an uncontrollable fire....doesn't bear thinking about.

Which why I will still reject the TO when the fire bell rings. Trying to weigh up the alternatives near to V1 is not part of a sensible gameplan to my way of thinking.
idg is offline  
Old 17th Jun 2007, 22:26
  #29 (permalink)  
Join Date: May 2007
Location: Both Emispheres
Posts: 226
July 2004, a 757 bound to La Havana, is at take off.
9 Knts before V1, engine fire n. 2 goes alarm

Commander, decides to continue. Both fire bottles are discharged, however the fire alarm stays on (later they will lean that the extinguishers managed to put off the fire, but the alarm remained because damage to sensors wires).

Commander decides not to discharge fuel and land immediately.
Passengers are evacuated, the investigation will find that a ruptured fuel hose caused the fire.

Report just published, in Italian with many portions are in English and clear photos.

The pilot was commended and nobody questioned that he exercised his command authority is a sensible manner during all phases of the emergency.
el # is offline  
Old 18th Jun 2007, 12:06
  #30 (permalink)  
Join Date: Jan 2007
Location: UK
Age: 74
Posts: 116
once saw a channel express F27 which had an engine fire just after take off, after take of, the fire was so severe they did a procedure turn to land on the opposite direction rwy, having seen the damage caused by a few minutes in the air, if they flew a full circuit to land on the correct rwy, I doubt the the crew would be flying today, the damage to the engine wing was pretty horrific.
pilot999 is offline  
Old 18th Jun 2007, 12:34
  #31 (permalink)  
Join Date: Apr 2001
Location: various places .....
Posts: 6,513
At the risk of being controversial, it is important to note that the Industry's operations are based on risk assessment and risk management.

For the very great proportion of occasions and events within that set, the "standard" approach will work pretty well and is commended. We note that the standard procedure is not necessarily the best but is structured to provide a high probability of a successful outcome.

However, we must accept that, infrequently, circumstances are such that the usual procedure may be quite inappropriate .. should we vary our actions to suit ? do we have the capability even to detect the subtle differences from the norm ?.. is there even a sensible answer ?

Industry history has numerous examples of good outcomes and bad following out of left field unusual situations ... I suggest that it comes down to a mix of knowledge, skill ... and a very large helping of good or back luck .... which determines the ultimate outcome.

I think back to just two tragic cases where the crew apparently did all the "right" things ... but died with their passengers ... [Concorde at CDG and the DC10 at O'Hare]. Would the outcomes have been better had the Concorde been dumped unceremoniously back on the ground ? ... had the DC10 maintained the initial higher airspeed rather than pitch up to achieve V2 ? ... hard to say with any certainty at all.

United 232 .. I suspect Al Haynes et al would concede that Lady Luck played a part in keeping the toll as low as it was ....

While we push standardisation for a bunch of very good reasons, flying generally is not about guaranteed, black and white outcomes ... it is about risk and probabilities ... about loading the dice towards the desired, favourable outcome .... about constraining and controlling ill-disciplined operational behaviours ... etc ... etc....
john_tullamarine is offline  
Old 18th Jun 2007, 21:40
  #32 (permalink)  
Warning Toxic!
Disgusted of Tunbridge
Join Date: Jan 2005
Location: Hampshire, UK
Posts: 4,011
Yes, but if you are below V1 and the fire bell goes, you're quite simply a dork if you take it airborne. No ifs, buts, whatever. To consciously take a potential fire airborne when you are already on the ground and freely able to stop, even on a limiting contaminated runway, show peculiar judgement. One needs to go into a darkened room and re-examine one's decision making processes. Period. There is no exception.

Next question please!
Rainboe is offline  
Old 18th Jun 2007, 22:37
  #33 (permalink)  
Join Date: Jan 1999
Location: hongkong
Posts: 187
El thanks for the link...interesting reading (well looking at photos cos my Italian is not good! ) and Rainboe, yes I'm still in your court with the stop call. JT as ever good comments. Pilot, yes the F27 engine installation puts that a/c at much more risk of severe structural damage from an engine fire, but in podded installations is the question here.

I suppose what I'm really asking is are we still examining the correct basic failure with the traditional V1 cut and engine fire? Whilst I agree it's possibly the most serious incident we could face from a handling sense, the industry data tends to point to more human factors issues as being where we need to concentrate our focus to bring down the accident rate.
Oh yes...and having reasonable Smoke procedures that are simple and workable......don't get me on that one as it's my favourite hobby horse and I would be accused of thread creep again!
idg is offline  
Old 19th Jun 2007, 08:54
  #34 (permalink)  
Join Date: Sep 1999
Posts: 542
There is no time to assimilate information whist on the takeoff roll so they make the decision rule-based.Its cut and dry.Below V1 you reject,at or above,you go.Its one of the few scenarios in aviation that is like this.Why do you think that poor Concorde pilot took his crippled aircraft to the skies?
As for ever taking a fire into the air below V1,well if you realized at high speed that the perf calculations were for another runway then you might push the thrust levers forward and elect to go at V1-10.The old eyeball method will tell you what is best.
Rananim is offline  
Old 19th Jun 2007, 08:57
  #35 (permalink)  
Join Date: Jan 2002
Location: UK
Posts: 152
The fire bell is never inhibited automatically on any aircraft that I know of. It can be inhibited by the crew, but other visual warnings remain.
Actually Old Smokey not quite true.

B757 Operations Manual:

'Warning Inhibits

The Master WARNING lights and fire bell are inhibited for fire during part of the
takeoff. The inhibit begins at rotation and continues until the first to occur:

400 feet AGL, or
20 seconds elapsed time

If a fire occurs during the inhibit, an EICAS warning message appears, but the fire bell and Master WARNING lights do not activate. If the warning condition still exists when the inhibit is removed, the fire bell and Master WARNING lights activate immediately.'
Fat Dog is offline  
Old 19th Jun 2007, 09:00
  #36 (permalink)  
Warning Toxic!
Disgusted of Tunbridge
Join Date: Jan 2005
Location: Hampshire, UK
Posts: 4,011
What interests me, apart from this thread of whether to sto with a fire before V1, is what to do after V1 with a fire. Classic training is to handle the emergency, climb, clean up, Mayday, S/E procedures, circuit and emergency land. A good 10 minutes minimum with possibly an uncontrollable one burning. Thinking of BOAC 707 1967 LHR doing that and burning out, and Airtours MAN 737 about '88 that could have ended up airborne with a 6 inch column of fuel on fire pouring out of the wing, and many other incidents where fires don't give you that time. So, you have an engine fire, do you do the classic, or do you leave flap alone, 80 degree course reversal, and land reciprocal as soon as poss? We are all coming round to the thought now that with a fire, every minute you save could save you.

(Please! ONLY experienced large jet jockeys PURRLEASE! Or clearly state you are not if you have to interject).

Last edited by Rainboe; 19th Jun 2007 at 09:10.
Rainboe is offline  
Old 19th Jun 2007, 09:41
  #37 (permalink)  
Join Date: May 2007
Location: Right seat
Age: 39
Posts: 47
In case of ongoing fire in VMC stop climb in Acc Alt and depending on the airport layout make visual on fastest available rwy

IMC = radar vectors for fastest available ils again depending on airport layout e.g. crossing rwy

Everything prepared in fmc and setup wise and briefed in t/o emergency briefing
danishdynamite is offline  
Old 19th Jun 2007, 10:02
  #38 (permalink)  
Join Date: Apr 2004
Location: Rome
Posts: 761
Engine fire just below V1, is it always correct to reject take off?

Boeing asks you to be so kind to stop takeoff below V1 for an engine fire. Is it a real fire ? You will discover it later on. If you stop take off above V1 then this is not correct. But you already know that a few knots before V1 you will probably end up by rejecting above that speed, especially if it is the fourth leg of the day by night. Next time you go in the sim try to reject within 5 - 6 knots from V1. Do it 10 times and try to get some statistics from that.

I-2021 is offline  
Old 19th Jun 2007, 10:51
  #39 (permalink)  
Nemo Me Impune Lacessit
Join Date: Jun 2004
Location: Derbyshire, England.
Posts: 4,042
Rainboe - If I got a fire on the -400 after V1 I'd pull the gear up, leave the flaps where they are and thus keep the speed down for a tight circuit or course reversal, depending on airport. Minimum time in the air being the aim.
parabellum is offline  
Old 19th Jun 2007, 12:19
  #40 (permalink)  
Warning Toxic!
Disgusted of Tunbridge
Join Date: Jan 2005
Location: Hampshire, UK
Posts: 4,011
All sim training focuses on doing it properly, and in good time: climb straight ahead, handle the immediate emergency, continue, retract flaps no turning, then think about returning on one, with a very long downwind leg to fly. I agree an early return is needed, but I'm not sure you have that long. Maybe an 80 degree low altitude course reversal/land back on reciprocal, on one engine might be pushing one's luck a bit, but I think there is a case for training: 'get this sucker back on the ground as soon as possible- no! That's too long!'. In other words, a very rapid, immediate low level emergency circuit. Perhaps even briefing before take-off whether another cross runway is even quicker. But we are not trained to even think like that, and do it in the sim and you will be hammered. But I would far rather get back on terra-firma and hand it to beefy firemen than try and heroically deal with it in the air, then land.
Rainboe is offline  

Thread Tools
Search this Thread

Contact Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

Copyright 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.