Engine Fire

[haaron]

In a turbo prop, in flight, if the T-handle/fire handle illuminates indicating an engine fire, would there be any other indications of the fire on the engine gauges (ie. high ITT, excessive fuel flow etc) or. Is it possible to confirm the presence of a fire by looking at the gauges or looking at the engine? If there were no other indications could you be certain that the illumiated handle was a false alarm? Would you shut it down if everything seems fine (other than the big red handle)? Thanks.

[Golden Rivet]

Unfortunately there will be no other indication of a fire.

You may notice an increase in fuel flow if you have a honking big fuel leak ( only if downsteam of the fuel flow transmitter though )

There is also the possiblity your fire may not be fuel related. Hydraulic fluids and oil burn well.

[OnTheStep]

and you'll really be guessing in a minute once the transducer loop has burned through and the handle light goes out :uhoh:

[Miserlou]

....And the FIRE handle is only so called so as to give you an idea what it's for.

The detection loops only indicate a change in potential difference which is due to an increase in temperature, such as may happen if there is a fire.

The only aviation guessing game I like is the Frankfurt Left or Right prize draw!

[Sheep Guts]

Well if you go through your drills and shut down the engine. Then check for fire if the fire is still there ie, T handle illuminated then continue with Emergency Shut off valve and Pull that dam handle. Assuming your talking Otter ? :)

Land ASAP,, if it isnt out, you may have to ditch! In a light twin you have around 5 minutes before structural damage affects your aframe. Ie. flight characteristcs. SO GET IT ON THE GROUND ASAP IS ALL I CAN SAY.

I used to fly Old King Airs that had thermal loops and the Sun at the rowrong time of day gave Fire WARNINGS on the announciator panel.

Regards
Sheep

[411A]

At one company not all that long ago, was informed by the Flight Engineer concerned, that the Captain, on noticing the light in the number one engine fire handle illuminated (and the fire bell ringing) decided, all on his own, that there was really no fire, so removed the bulbs from said fire handle, and completed the flight (across water) for the remaining four hours.
Should mention that this occured in the climb from the departure airport.

Reminds me of the old song..."all the monkies aren't in the zoo, every day you meet quite a few...."

Hogy Carmichael, circa 1934

[mono]

Sheep Guts,

The KingAirs you mention were not fitted with thermal loops but Infra Red light detectors. That's why a glorious red sunset/sunrise would trigger the engine fire warning, because the light entered the engine cowls.

The 'fix' for this (though it wasn't a 100% fix) was to fit a steel cresent plate to the exhaust flange to reduce the chance of light entering via the gap 'twixt cowl and jet pipe.

[sean1]

''The KingAirs you mention were not fitted with thermal loops but Infra Red light detectors''.

That is amazing! how about sending the designer on a long over water flight during a glorious sunset.

Reminds of Carparks designed by people who don't drive/park cars.

[Dan Kelly]

modern turbo-prop engines are so tightly cowled that it is unlikely that any external sign of fire will be visible. As noted above, there is not likely to be any engine instrument indication of a fire.

Only a very brave person would decide not to take the fire warning as real and ignore it. As a generalisation, most turboprops will fly safely with an engine shutdown, provided the recommended techniques are used.

So, to answer your second last question, there will most likely be no other indications of an engine fire other than handle & bell.

To answer your last question. I would not hesitate to shut the engine down if the handle was illuminated and the fire bell sounding. To do otherwise is to me, allowing the tail to wag the dog, as it presumes that the warning is false and so I'll ignore it in case I shut a good engine down. When the thought process should be, I've got an engine fire, I'll shut the engine down, land and have the fault investigated.

The dilemma would be if one of, the fire handle illuminated, or fire bell sounded, but not both. In this instance one might consider the possibility of a false indication and depending on a whole lot of factors one migh not shut down the engine if over inhositable terrain. However if near a suitable airfield, one would possibly consider a landing and investigation.

With reference to KingAir false fire warnings, if memory serves me, the first action on receipt of a fire warning in a LingAir is to turn through 90° and see if the warning goes out. If it does and it was daylight when the warning sounded, it may be assumed that the warning is false and a result of sunlight triggering the sensors.

[Col. Walter E. Kurtz]

So 411, was it a fire for real, or what??????

[lomapaseo]

Most engine true fire warnings are not fuel fed combustions but rather hot air leaks from bleeds etc. Thus pulling a engine back to idle may be enough to silence the alarm.

Shutting an engine down in a critical flight regime at low altitude is not easy to restart if you later need it.

I believe that many FCOM recommend pull back to idle and only to fire a bottle (which cuts the fuel) if the fire bell remains.

[Elliot Moose]

lomapaseo
I would suspect that you are thinking jet FCOM here. I've never seen such a one on a t-prop.

Back to the question at hand, I would always treat a fire as real. Even at low speeds, any indication that would be visible would be about a km behind the aircraft unless you had a whopping big fire going. I would always pull the handle and head back S/E unless there was no way to stay aloft on one. My one experience was with a max weight HS748 on a hot day (28C) at 400' AGL. As turboprops go, that is about as bad as you are going to get. We shut down and returned on one. The only problem was that the captain selected gear down a bit too far out, and we burned A LOT of water/methanol to maintain until we made the runway! Turned out to be a bad fire wire, but who knew?

Given just about anything else with a turbine engine, flying on one with a professional crew (as opposed to a weekend flyer who logs about 60hrs a year)is much less dangerous than living with a POSSIBLE fire on board.:ok:

[Sheep Guts]

Yes mono thanks I stand corrected Infr Red sensors were fitted. Really wierd really.:uhoh: :rolleyes: ;)


Regards
sheep

P.S. allways do your Memory immediately dependant on Type and pull Out the QRH..... TO CHECK AND DOUBLE CHECK

[HotDog]

411A, the nacelle temp indicators would have been a help if it's a 747 you are talking about?

[411A]

Hot Dog,

Yes, suspect they would, however was a TriStar.
Simply cannot understand why a so called professional would take chances this way.

The company took a very dim view of the situation when they found out. This was after he told the Flight Engineer not to put anything in the tech log.

[pigboat]

Moose, did you ever get an engine fire indication on the Dart, after shut down, due to high internal temps? That can happen, although it never did to me in about 15,000 hours on 'em.

[fruitbatflyer]

Never had a fire warning on a Dart after shutdown, but some of the earlier Dart 6 machines would give a momentary warning during a prolonged climb in very hot, like ISA plus 25 or more, conditions. The trick was to lower the nose and get some airflow going and the warning would quickly stop.
With this knowledge in my background, I once nearly got myself and crew killed while doing some hot weather/short runway certification work on a much more powerful version of the same aircraft type. We were doing successive water meth takeoffs to measure unstick distances, followed by a split arse reversal turn to dump it back on the reciprocal direction runway, roll through, line up and go again. So it was getting pretty warm in the engine bays, and when the fire warning came on momentarily at about V2 plus 10, my initial reaction was to ignore it, especially as it did not remain on as speed increased. Fortunately, a pilot sitting down the back heard the bell, looked outside, and as luck would have it, saw flames on the inboard side of the cowl. He alerted us to the fire and we promptly did the drill and landed.
A combustion chamber had burnt through, heating up the firewire, then turned into a blowtorch and taken out the firewire and just about ate through some of the engine control linkages
in the 30 or so seconds that it took us to do the drill.
We did not observe any loss in engine power, or change in TGT, presumably because the water meth was pouring in at a great rate to compensate for the inefficient combustion chamber.
So, after that experience I will always, but always, at least shut the engine down just to get the fuel out of the equation. Whether to activate the fire bottle is really dependant on what the checklist says regarding warnings present, but the moral has to be 'if in doubt, fire the bottle'.

[Elliot Moose]

pigboat,
I have less than 2000 with the darts, and I've only heard the rumours of post shutdown fire indications. Other than the false alarm I wrote about above, the only time I heard the bell in flight was when Lyle Griffith got bored:D

fruitbat
That sounds like one spooky trip! Right up there with the 748 that had it's water meth tanks filled with waste varsol and fuel. Scary at the time but positively petrifying afterwards when you see what actually happened.

[None]

"lomapaseo Most engine true fire warnings are not fuel fed combustions but rather hot air leaks from bleeds etc. Thus pulling a engine back to idle may be enough to silence the alarm. "

Bleed air leaks can be trouble.

There was an event where a 13th stage bleed air leak had hot air flowing over an area where fuel vapors were possible ( I cannot recall if it was a pump housing). Because of the way the leak flowed, there was no fire indication, only erratic changes in N1. Idle brought all indications back to near-normal, but a fast return to the departure airport (from 40 nm out to sea) was accomplished. When the mechanic opened the cowl, the look on his face was memorable, as he pointed out the possibility of fuel vapor ignition. It would have been better to shut it down in-flight, but there were no indications to lead us that way.

[pigboat]

Geez fruitbat, that's pretty damn scary. Make a believer outta a person.
Apparently the after shutdown warning could occur after a fairly long ground idle at high ambient temps and was caused by high oil temperatures.

The DC-4M was a pressurized version of the DC-4 re-engined with RR Merlins. The early models had no shortage of teething problems, not the least of which was false fire warnings. I had a friend who flew them as F/O, and one day between Toronto and Winnipeg all four went off at once. Walt said he nearly soiled his skivvies, but the Captain just said a few choice words, cancelled the bells and whistles and kept on going. :uhoh:

Moose, which 748 was that, the one on Anticosti Island or the one in Churchill?

[Elliot Moose]

I heard about Anticosti, but the one I saw the pics of was up at Churchill. Larry Hearn used to show them at groundschool recurrents. I talked to some mtce guys who saw the engines. They said it was a wonder the whole ship didn't go BOOM!

It seems to me they had two fire warnings in there though--right about the time both fans went zzzziiiiiippppp-----BANG! What do you do in that case? (except turn final and land on the frozen river!):uhoh:

As for the DC-4M (that was the "North Star", I believe ) "a few teething problems" might just be an understatement there! I heard a few wild stories about those multiple engine fires happening a long way from shore. The way I heard it, at least two of the engines were there based on the assumption that it wasn't unlikely that the first two would quit enroute. Great idea, but those WWII surplus fighter engines just weren't made for the long haul stuff.

[pigboat]

Yeah, they were lucky the river was where it was. The Anticosti guy had uploaded the stuff outta UL, a combination of varsol, MEK, acetone etc. They did a dry takeoff in UL, and on the wet takeoff from the island, the right engine blew just before V1. Golden horseshoe time.
The US Navy had a G1 where the F/O armed the w/m on takeoff right after the gear retraction. They'd been doing wet departures all summer, and their procedure had the PNF reaching up and turning the w/m off first thing after retracting the gear. The first cool day, they did a dry takeoff, and the PNF reached up without thinking and flipped the w/m switches, from off to on. They overtemped both engines but got it around and landed. I saw the pics at Flight Safety. The engine mounts were visibly twisted out of true. :uhoh:

[411A]

Similar ops with F.27's in Libya many years ago with an oil company.
All wet takeoffs, all the time.
Standard procedure was to switch W/M off before climb power (14,200rpm) set.
Suggested to the chief pilot that according to Fokker, this was not a good idea, performance wise.
He looked at me long and hard (probably thinking what does this young wiseguy know)...and said, yep you're right, type out a new checklist.
Couldn't get out of the office for two weeks:{ as he found more for me to do as well.
Learned a lot from these older guys.
Then, when flying with him a month later, he starts looking for ground fine at 50 feet on landing.
On taxi back he says...did I really do that?
On his desk a week later was a big note to himself...thou shalt NOT select G/F before landing.

[Elliot Moose]

Yahooo, water on at 50'!! What a wake-up that must have been! I guess that's why we always pulled back to 14500 as soon as we cleared the trees instead of flipping the switches--you always can get it back if you get scared, and you won't ever turn it on by mistake.

I always wondered what would happed if you turned them on after 15000 was set, now I know!:ok: I wouldn't have been surprised if exploding cans might have rung the bell after somebody did something like that.

[pigboat]

411, yeah not a good idea at all to select it off too soon. On our checklist it was about item number six or so. Gear, power, flaps, temps, fuel heat, water.
Somebody selects GFP in the air, he's sure trusting those squat switches to keep his butt in one piece, ain't he. ;)
I'm guessing that was a Fokker machine. I've never flown that one. I believe it had a slightly different system for selecting GFP than the Fairchild.

[Hudson]

I sometimes feel uneasy about the Boeing advice not to take action on an engine fire until at least 400 feet after take off. This seems to imply that an engine fire in (say), a 737, is no big deal.
With a engine fire warning at V1 at a WAT limiting take off weight, it could take some time to climb to 400 ft particularly if for some reason the gear is not retracted immediately. By this I mean a PNF forgets to call positive climb and the PF is so used to hearing positive rate that when it is not verbalised he instinctively fails to call gear up.

The worst I have seen in the simulator is around one minute of fire warning before the crew take the first recall action. It seems that a dangerous false sense of security is engendered by strict adherance to a Boeing SOP that is more concerned with the possibility of wrong identification than extinguishing what may well be a blazing out of control fire.

Unless the crew get visual confirmation of severe fire from the cabin crew or outside observers, it is probable that the crew have no idea of the severity or otherwise of the engine fire. After all, all the crew can see is a red light on a fire handle and they would not know if its an itsy bitsy fire or a roaring inferno.

In the simulator I have seen the PNF have writers block when directed to carry out the recall items for an engine fire at V1. In one case the PNF hesitated an inordinate time because he was trying to remember in time of extreme stress whether the first recall item was throttle closed then auto-throttle disconnect - or the other way around. Meanwhile the PF waited impatiently while the fire burnt away vital bits and pieces. Very worrying.

[lomapaseo]

Hudson

Be assurred that Boeing took under consideration considerable experience with engine fires shared by all manufacturers data banks.

All of your "what ifs" were postulated and obvious "factuals" as well.

It was noted that the greater risk with uncontrolled engine fires was on the ground while the greater risk with crew error under stressfull situations was beyond v1.

You are probably correct in pointing out that some "what if" scenarios are not properly accounted for under the recommended procedure, but the idea was to save more lives in our imperfect world.

[Hudson]

Iomapaseo.

Thanks for the good advice. You have given me something to think about. I keep on thinking though, about the advice that I received at first hand from a gnarled old Boeing instructor pilot called Joe Z back in 1976, that the cockpit drills and recommendations were actually aimed at the weakest link - third world crews. Letting a fierce engine fire burn until above 400 ft before taking the first action still niggles me.

[HotDog]

Hudson, I also knew Joe Z. What he told us was that the Boeing training philosophy was based on the A & Ns as a common denominator. Our SOPs also required 400' before actioning an emergency or abnormal checklist. An engine fire warning, even if it is genuine does not mean power loss of that engine. Maybe if the flight engineer on the Air France Concorde had not initiated the fire drill on No.2 engine before it was called for, they may have at least cleared the hotel building they crashed into, who knows? How long does it take to climb to 400' with TO power?

[E120]

Even if you are not sure, shut it down and pull the #$*%*# handle! Flying on one engine is not a big deal in most turbo props. And finding out that you have shut down a good engine due to a faulty warning is by far less worse than... A red fire warning means FIRE to me! (regardless of the detection system; I have shut down and extinguished a good engine on a Beech 99 (King Air) after a faulty warning; I am glad I did).

Happy Flights :ok:

(Off course no drill below 400' (500')...;)

[411A]

<even if you are not sure, shut it down and pull the *!^%#@* handle>

Hmm, I wonder.

Scenario to consider.

On departure JED (bound for JFK) a B747SP developed high vibs from engine #2 at 400agl. Captain retarded the throttle, vibs reduced. When the throttle was once again advanced (bad idea), vibs returned (bigtime) and the engine came apart, pieces of which entered the intake of number one engine.
The number one fire pull handle illuminated (along with the fire bell), bell was silenced, and climb continued, with engine #1 still producing full rated thrust. RR engines, so would expect nothing less.
The Flight Engineer, not being content with the situation, without saying a word, reached up and pulled the number one fire pull handle.
The aircraft was now at 900agl, on two engines, at heavy weight.
Superb flying by the Commander (PF) prevented a disaster.
APU was started, fuel dumping was commenced immediately, and the aircraft returned for an overweight landing, pronto.

Sometimes, engine shut down too soon is a very bad idea.

[Dan Kelly]

Do you know what the Commander said to the FE afterwards? I suspect it might have been in French! ;)

I believe a similar thing occured with the Concorde crash a few years ago, FE shutdown an engine without being instructed to, leaving the heavy aircraft on two! :oh:

[411A]

Oddly enough Dan, the Commander was asked this very same question next day by the equipment manager, and his reply...

'too darn busy at 900 feet descending to hold ground school...'

They were very lucky. Fortunate in that this was the -SP model, good performance.

And you won't find this incident in any data base, kept very quietly in house.

[Dan Kelly]

I can well imagine being too busy @ 900'. Once it was over though, I think I'd have to say something!

[PAXboy]

Thanks for some interesting stories, as always. I shall pass on the accidental selection 'on' of water/meth, to my nephew who drives J41s, many of them 'wet' equipped.

One example of a damaged engine still pulling strongly is the unfortunate Brit Midland 734 diverting into EMF. IIRC, the engine with the fire showed no other signs and operated as normal?

If I may, a fire-related question. When you discharge the bottle, where does it go?

Reason for question is: If airborne, and the bottle discharges into the core, then I would imagine that the extinguishant will be blown out of the back a split second later and not have time to have an effect?

[lomapaseo]

One example of a damaged engine still pulling strongly is the unfortunate Brit Midland 734 diverting into EMF. IIRC, the engine with the fire showed no other signs and operated as normal?

If I may, a fire-related question. When you discharge the bottle, where does it go?

Reason for question is: If airborne, and the bottle discharges into the core, then I would imagine that the extinguishant will be blown out of the back a split second later and not have time to have an effect?

Paxboy, your comments were so astounding to me that I fear I may be misreading them, but I'll try an answer.

I believe the Brit Midland 734 you are relating was the one that started with a flutter fatigued and relase of a fan blade in flight followed by surge sparks and vibration which greatly diminished as the pilot pulled this engine back a mite. Unfortunately he shut down the other engine feeling it was the bad un.

Subsequently when he tried using the broken engine during landing with throttle dithering the vibration broke a fuel line and it caught fire

The fire extunguisher bottles are there to protect the pylon and wing not the engine and as such they discharge outside of the engine within the nacelle area while at the same time shuting off fuel to the engine.

Does this answer your question or have I missed it?

[PAXboy]

lomopeso: Many thanks for putting me right on the BD 734, obviously way out of touch on that.

As to the extinguishant - thanks, yes that is what I had presumed.