View Full Version : B737 or Jet aircraft generally Tail-Pipe Fires

3rd Aug 2007, 14:14
The B737 QRH gives direction on procedure to combat a tail-pipe fire. Because the engine fire detection system does not cover the tail-pipe area, it is presumed the alert will come from outside sources. A Boeing source (have forgotten the details) indicates that components of the engine remain hot enough for up to 20 minutes after shut down to ignite residual fuel.

I wondered if Pprune readers can furnish details of their experience of tail-pipe fires and the circumstances. These would be useful for discussion points during simulator briefings as one very rarely hears of tail-pipe fire reports.

3rd Aug 2007, 14:21
727, 300/310, 320, 340 never had a tailpipe fire. Only in the sim.

Fly safe

Gary Lager
3rd Aug 2007, 20:06
Have had a self-extinguishing tailpipe fire during a second start following IGN failure on a B737. After our first start attempt(s) with a failed igniter, we pulled back onto stand and got an engineer to inspect and ADD the failed igniter iaw the MEL.

Second pushback, engine start - all appeared absolutely normal in the flight deck. We received a cabin crew call (unusual - they wait until taxi before giving the cabin secure) - the no. 1 had had a call from the back that passengers had seen fire/flames in the engine, were concerned, and had contacted the rear crew, who informed the no. 1.

We asked the chap on the headset (Czech, but who spoke good English) if he had seen anything unusual during the start. "Yes there were flames but it's all OK now". Good job he was there to monitor the start, eh?! Anyway, fairly obvious that the 'fire' was just pooled fuel from the first failed start attempts and that nothing was wrong with the engine. Pax PA made along the lines of "you know what happens when you put too much lighter fluid on your BBQ..?" and all normal after that.

3rd Aug 2007, 23:31
With a cynical hat on ;) The best response to a G/C call of "tailpipe fire" is "what... errrr say again, errrr.... oh tailpipe fire" to which the reply will probably be "well there was, but it's gone out now" "OK - engines running - thanks very much" :ooh:

4th Aug 2007, 05:29
Scene, GQNN, two years ago.
L1011 on the parking stand, ready to start engines, but no APU, so external pneumatic air and electrics are used.
So far, so good.
Captain attempts to start the number three engine.
It winds up OK, but after starter cutout, runs down...reason unknown.
Captain does not close the HP fuel and ignition switch.
Tailpipe fire ensues.
Tailpipe fire drill not carried out...reason unknown.
Fire gets bigger...a lot bigger.
Ground Engineer, who is by the R2 door, notices the fire and races to the down galley, jumps out of the galley service door, and uses a large Halon extinguisher on fire...meanwhile, another ground engineer goes to the FD and suggests to the Captain that if he does not want the right hand wing to burn off, he had better damn well switch OFF the fuel and ignition switch.
Captain does so, just as the airport fires services arrive.
No outward damage is observed, and after a detailed engine/airplane inspection, the aircraft is dispatched to destination.
Said Captain has now retired to (I think) Spain, and it is just as well, as clearly proper tailpipe fire procedures were not followed, which is not at all satisfactory.
Gotta know the proper drills folks, otherwise big trouble can develop, darn quick.

4th Aug 2007, 12:57
Tailpipe fires are not hazardous as long as you have airflow through the engine, at least have the starter motor on. If that is not possible (PAX milling about the inlet after self evacuating) then cutting the fuel as quickly as possible will reduce the damage to the aircraft.

I don't recall an incident where a tailpipe fire alone, burned through an aircraft firewall although there have been several where the aft wing was severely damaged while on the ground.

chemical alli
6th Aug 2007, 08:08
running a 767 cf6 aircraft on eng ground run and tested fire handle due to replacement,forgot to close the fuel cutoff lever and then went for a restart.due to fuel cutoff lever being in the run position before 20% had raw fuel vaporising and streaming out the back. Once lightup occured the fire ball was sucked back around into the fan and up over the wing.
the ground observer was last seen running for his life still trying to tow the aircraft with him by the headset.scary but very comical.no damage done and egt within limits

6th Aug 2007, 13:59
To all contributors above. Thanks a million for your input. Intend to print them out and use them as excellent briefing material on the subject. I have seen "torching" during engine start of JT8D's in the 737-200. Alarming sight at night but flames quickly disperse. I am not quite sure it could be classed as a tail-pipe fire though. Don't think so.

7th Aug 2007, 21:32
I had the misfortune to have a test cell operator panic during a startup - the engine had preservative oil in it, thus a delayed lightoff and tailpipe fire. He terminated the start then re-engaged the starter - with the result being a sheared tower shaft between the gearbox and core engine. (That's an interesting problem to sort out, BTW - the apparent core rotation on the instruments is simply the starter turning the gearbox, but the engine is disconnected :8 )

Anyway, no harm done with the low-energy fire in the tailpipe, but we had to fit a new tower shaft... :uhoh:

8th Aug 2007, 21:40
I was a dispatcher 2 years ago and while providing a headset departure, a tail pipe fire occured during a V2500-powered A319 engine start. Wind was strong and its direction opposite to engine flow. Impressive experience...

9th Aug 2007, 18:42
Have also seen the result from a 'crash engaged' starter motor, not pretty, wind and disengaged clutch pawl springs do not mix!

Have known guys whilst ground running to throttle the engine up slightly to blow out a tail pipe fire, as per their ground run manual. :hmm:

I remember meeting an aircraft with no apu available, guy shutdown both engines simultaneously, a tail pipe fire occured and we had no way of blowing it out quickly, luckily found an extinguisher! :D

9th Aug 2007, 21:22
Let me give you guys one better. I fly the mighty CRJ, on which (as on many aircraft) the APU is deferrable. Let's imagine the following scenario: we land with a deferred APU, taxi in, shut down #1, then #2, whose tailpipe promptly catches fire. Now, we have a memory item for this situation and it is this:

AFFECTED ENGINE ---------- Dry motor until ITT < 150C or starter limit

Question: how in blazes am I supposed to dry-motor it, if the APU is deferred?

9th Aug 2007, 22:57
With an APU as a deferred defect, shouldn't you dispatch with a proviso that your destination(s) have been advised to provide you with ground power and air? Maybe not - but in my experience, we would not shut down the last engine until the previous engine had reduced below a certain N1 rpm. Ground air cart would then have taken over as 'motoring air'.
On a previous fleet- L1011 TriStar, with the early RR RB211's, tailpipe fires were not infrequent, and with spectacular visual displays!

Swedish Steve
10th Aug 2007, 20:47
On a previous fleet- L1011 TriStar, with the early RR RB211's, tailpipe fires were not infrequent, and with spectacular visual displays

Yes when I was first on the L1011 around 1980, when the APU was inop we always closed the Nbr 3 engine last by pulling the fire handle. This ensured there was no fuel left when the engine stopped. The reason was that the HP Fuel valve was unreliable and the cause of the tail pipe fires. When the engine had stopped you closed the fuel/ignition switch and an engineer checked that it was closed. Then you reset the fire handle.

Swedish Steve
10th Aug 2007, 21:22
I can remember two tail pipe fires in my time.
In BAH we used to do compressor washes on the B732 JT8 engines using a mix of demineralised water and 5% JetA1. One day, unknown to me the rig had been filled with nearly neat kerosene! On the post wash run the fuel in the jetpipe caught fire during the start, ran out and then ran back under the engine. Being quick thinking (in my youth) I let the engine run up to idle until the jet pipe fire went out, then shut the engine down and extinguished the flames under it with a fire extinguisher which we had with us.
The other one was a CX B742 on the ramp. For some reason the CX engineer wanted to test the ignitors during the transit. What you do is to trip the HPSOV CB, then open the fuel/ignition switch. He tripped the ignitor s CB instead. When he had walked down to the engine to listen to the ignitors, the fuel had ignited itself in the hot engine. We changed the engine for him.

11th Aug 2007, 05:14
I experienced a tail pipe fire on a B737-300 aircraft several years ago after an MEC change, during first engine start, closed start valve and motored for 1 minute, then a second start was uneventful.
I noticed an orange glow from outside, as the headset man was a bit slow informing me of the event. Late afternoon, sun going down, snow around.

11th Aug 2007, 19:42
Ground air carts are never in abundance at LHR unfortunatley!

12th Aug 2007, 11:55
The most difficult thing to do is the PA announcement after a tailpipe fire...

12th Aug 2007, 12:45
LEM. On an allied matter, what is the policy in your company regarding a warning announcement to the cabin crew and passengers in event of (say) an aborted take off due to something like a fire warning. After the aircraft is stopped does the captain first make a PA and then conduct the QRH Recalls - or do the Recalls come first (fire handles, firing the bottles etc) and only then is the PA made?

12th Aug 2007, 13:33
An interesting question, Centaurus.
Clearly recall parts of the drill are important, but so is having the punters calmed...and not heading for the exits, enmass.:}
And, this brings up another point.
If for some reason, all electric power (except for the hot ships battery bus) is lost due to engines being shut down in a hurry, do you still have a functioning PA system?
On modern aircraft of course, the answer is yes, but this was not true in some earlier jet transports, for example, the B707's that Braniff had purchased new.
Some of these found their way to other carriers, and this was not realised, until I pointed it out to a check Captain during a proficiency check in the companies sim.
He was sure he was correct, and I knew darn well he was not, so out on the tarmac we went, and tried the PA with all engines shut down, but with the battery switch ON, in an 'ole Braniff 707 that the company had...sure enough it didn't work, and he had to eat crow on the spot...this was of course after he had signed my check form as 'completed to a very good standard'.:E

12th Aug 2007, 16:20
Takeoff aborted, aircraft stopped, parking brake set, speed brake down, order the FO to advise Tower "Call ATC Mayday", or "Call ATC abort takeoff" if less serious, PA "Attention crew at stations!" twice, then fire recall items, if fire extinguishes, PA " Attention Captain speaking: remain seated!" twice, if fire still on, perform EVACUATION NNC, and when it says Advise the cabin the evacuate, PA "Evacuation" 3 times.

The Captain does all PAs.

12th Aug 2007, 16:38
It can happen!!



12th Aug 2007, 17:26
One day, we had an igniters problem. Wet start. Prior to 2nd engine attempt, we were motoring engine according to QRH.
2nd start, from cockpit OK.
Departure from one small airport and only AFTER take-off they advised us, that there was a flame during an engine start.

No ground crew training at all!!!

For what are they down there? :ugh:

12th Aug 2007, 22:16
As an engineer I have been involved in two.

The most recent a 757/RB211 tail pipe fire occured as a result of low APU duct pressure and a slight tail wind. The engine suffered a hung start and following shut down, I went out and had a chat with the crew via the intercom. As I was talking I noticed smoke coming out of the front of the right engine and advised there may be a tail pipe fire. The captain confirmed rising EGT and initiated a dry motor while I went to have a look. After an age the captain said that he had to stop as starter duty cycle was at the limit. but the thing was still burning slightly. Just as I was about to get the fire crews to put it out with some CO2 it went out of its own accord. A quick inspection and confirmation that EGT had not been exceeded and it was on its way (after an ECU reset to restore duct pressure)

The other many moons ago was much more exciting.

The a/c was a 707 JT3 and the tail pipe fire occured after an engine run following replacement. On being advised of the fire the usual dry motor was carried out but the fire was still huge at end of the duty cycle so the only option was to light her up again :eek:

The torching that occured as this was done was MOST impressive! Having then idled the engine for 10 minutes a normal shutdown was sucessful.

Do not be confused with torching and tail pipe fires. Torching, particularly after installation of an engine that has been inhibited, is quite common. There is a famous video of a 737/CFM56 which has 20-30 foot flames coming out of the back as it is started for the first time probably because it was inhibited. This causes a delayed light-up and sometimes some spectacular displays.