Engine fire warning on the ground? Evacuation?

[Bobik737]

Is it allowed to discharge two bottle without 30 second interval in case of engine fire on the ground in boeing737? FCTM b737 page 8.12? Give me advise please, how do you make decision for evacuation in case of RTO due to engine fire? Thank you!!!

[aa73]

Smoke and/or fire = evacuate.

No smoke and/or fire = hesitate.

[oxenos]

Don't just rely on the lights and bells. It is easy to forget that you can open the window, stick your head out and see for yourself.

[lomapaseo]

You seem to have posed two questions here, one having to do with discharging a second fire bottle and the other having to do with evacuation based on an on-ground fire

I see no harm in discharging a fire bottle on the ground, seeing as it shuts off the fuel to the engine, causes any air leaks or fire to subside and in most cases will extinguish a real fire confined to a nacelle. At the same time you sure have no need of engine power while stoppd on the ground.

The idea about waiting before discharging a second bottle is to determine if the first one made the problem go away giving one a chance to think what do do next (stick your head out the window, page the crew in the back etc.).

Based on the results of the above, now consider an evacuation.

I'll now take a deep breath and see what others have to say about this.

[BOAC]

seeing as it shuts off the fuel to the engine- firing a bottle does nothing to the fuel supply.

There is no time restriction on firing the second bottle. Evacuation - that is what you are paid to decide.

[Maurice Chavez]

Is it allowed to discharge two bottle without 30 second interval in case of engine fire on the ground in boeing737? FCTM b737 page 8.12? Give me advise please, how do you make decision for evacuation in case of RTO due to engine fire? Thank you!!!You'll need to read it careful. It says:

If an engine fire warning light is NOT illuminated, but a fire indication exists or a fire is reported in or near an engine, discharge BOTH fire bottles.

As for your question in regards to evacuate or not, it is a tough call. You need to give it careful thought wether to evacuate or not, when in doubt, evacuate.

As Boeing points out, use all relevant sources to confirm fire is out...Make sure the airplane is parked in a position, that if the fire relights, it is on the downwind side....

[reivilo]

In my 737 ops manual in the chapter concerning evacuation - bottle discharge:
"Rotate and hold fire switches until the bottle discharge lights illuminate. In case of eng fire, discharge BOTH bottles in affected engine. Wait 30 seconds before discharging the second bottle in the affected engine as the time that the agent (halon) is on the fire is more important than the amount of agent on the fire."

[Maurice Chavez]

What section of the FCTM are you referring to and what is the date on your manual?

[porch monkey]

Pulling the fire switch does indeed cut fuel supply to the engine. The switch has to be pulled to arm the bottle, ergo, the fuel is cut off, no?

[catiamonkey]

As has been stated, the Halon 1301 used is a gaseous extinguishing agent. It works by being heavy and inert: it sits around and prevents oxygen from reaching the fire while absorbing the heat. Very little of it should chemically react.

The nacelle has been engineered to maintain the proper concentration. It should work a bit better on the ground since you're not moving and the atmospheric pressure is higher. Since its 5 times denser than air, it will stick around for minutes.

If you fire the second bottle too early, all you'll do is push out the existing Halon to the atmosphere and waste it. Another concern is that because how Halon absorbs heat, when it touches hot components they will rapidly cool and cause thermal shock and major engine damage.

I'd say to go ahead and pull the handles, but as the checklist says, pilot judgement is necessary before the first bottle. Wait 30 seconds for the second bottle, but evacuate in the meantime if necessary.

[BOAC]

This was actually queried at a fairly high level (I think it was in BA) and the word was there is no need to wait 30 seconds on the ground. I suspect, reivilo, that we are looking at company specific OMs , as my last company SPECIFICALLY detailed that you do not need to wait. We follow the book (subject to our discretion, of course!)

Pmonkey - correct, but the words were "discharging a fire bottle on the ground, seeing as it shuts off the fuel to the engine" - when the fuel is already off.

Incidentally, the logic in discharging both bottles when there is evidence of a fire in the vicinity is to avoid the bottles exploding in any fire and thus if you abort for some non-fire related event you need to consider before firing the bottles. The same reason goes for discharging the APU bottle.

[NigelOnDraft]

Leaving aside type specifics, waiting 30s to discharge a second bottle with a Fire on the Ground seems "unwise"? Surely that is delaying the Evacuation by up to 30s?

The company I work for's bottom line is you evacuate for 'Any Confirmed Unextinquished Fire'. That can be interpreted in a number of ways, but my thinking is along the lines of:

A Fire Warning (alone) is not Confirmed
'Unextinquished' is at the (final) point of the Evac decision.Whilst that decision could be immediate, in practice, while my colleague is working through the Fire Drill, I am confirming the Fire / communicating (windows, ATC, CC etc.). If it is confirmed, we will invariably now go for the Evac checklist. That requires certain actions prior the actual Evacuation becoming irreversible, and another chance to see if the fire has extinquished.

As ever, there is no "right" and "wrong". You make the decision, and unless it is patently wrong given the info you had at the time, you should be supported. Whether a more optimal answer subsequently becomes apparent is not too relevant - you can only act on the info and training at that time. pPrune will of course hang you, but what's new ;)

NoD

[FullWings]

...Halon 1301 used is a gaseous extinguishing agent. It works by being heavy and inert: it sits around and prevents oxygen from reaching the fire while absorbing the heat. Very little of it should chemically react.
I'm not a chemist but I was under the impression that the exact opposite was the case: the whole effectiveness of halon-like suppressants comes from their ability to interfere with combustion processes at the atomic level, once broken down by heat. The cooling/smothering effects are welcome but secondary...

See: SKYbrary - Halon Fire Extinguishers (http://www.skybrary.aero/index.php/Halon_Fire_Extinguishers)

[reivilo]

I suspect, reivilo, that we are looking at company specific OMs , as my last company SPECIFICALLY detailed that you do not need to wait. We follow the book (subject to our discretion, of course!)
You're correct, its quoted from my company specific OM.


Leaving aside type specifics, waiting 30s to discharge a second bottle with a Fire on the Ground seems "unwise"? Surely that is delaying the Evacuation by up to 30s?

No, you would not delay the evacuation because the order to evacuate is given prior to discharging any fire bottle:

7 Engine start levers (both) . . . . . CUTOFF
8 Advise the cabin to evacuate.
9 Advise the tower.
10 Engine and APU fire switches (all) . . . . Override and pull
11 If an engine or APU fire warning occurs: Illuminated fire switch . . . . . . . . . . Rotate to the stop and hold for 1 second

[spannersatcx]

Incidentally, the logic in discharging both bottles when there is evidence of a fire in the vicinity is to avoid the bottles exploding in any fire

The bottles will not explode as they have a pressure relief built in. Remember the little red discs on the pylons for 747 and near the apu, that was/is your relief indication, nowadays it's by a light in the cockpit of the modern jets.

[BOAC]

I guess it was taught as 'belt and braces'? There is no other reason.

[catiamonkey]

I'm not a chemist but I was under the impression that the exact opposite was the case: the whole effectiveness of halon-like suppressants comes from their ability to interfere with combustion processes at the atomic level, once broken down by heat. The cooling/smothering effects are welcome but secondary...

I've heard that, but I've also heard that's a traditional explanation. I've been told that it appears that by having a heavy inert molecule, you get plasma interactions which suppress the flame. Check out the DARPA instant fire suppression project, it turns out we know less of fire than we thought.

The new clean agents, Novec 1230 and FM-200 don't have any bromine, iodine or chlorine and are even heavier than Halon. The former of which looks like it's going to replace airframe halon completely on the A350.

[Bobik737]

What section of the FCTM are you referring to and what is the date on your manual?
Boeing FCTM 737 ,9 revision June 2010,page 8.12

[Bobik737]

Another simple question... RTO after engine fire warning in low visibility, information from ATC and nearby aircraft conforming fire is impossible to receive, parking brake is set, cabin crew informed. Engine fire memory action completed by captain or f/o?
Second bottle discharged after 30 sec interval?
What procedures of your company say?
Thank you!!!

[de facto]

Engine fire on ground after RTO in low Vis:Recall items and discharge BOTH bottles WITHOUT waiting 30 secs.
I believe the 30 secs in the air is in case you discharge one and the fire signal stops you may keep the second bottle in case the fire comes back....on the ground if the fire comes back after both bottles discharged..evacuate.

If still sign of fire :Parking Brake set,Speed brake stow,Call for flaps 40 then QRH checklist.
When time comes to call for evacuation, check fire situation one last time(may have extinguished by then).

Fo will advise tower of evacuation and approximate position for fire rescue.


Capt becomes PF if stop call is made hence he performs recall items.

[Maurice Chavez]

Capt becomes PF if stop call is made hence he performs recall items.Actually NOT so... He is PF and only does the thrust lever during the memory items, HE DOES NOT carry out memory items, same in the air or if F/O is PF, PF only handles the thrust lever during memory items.

[reivilo]

Parking brake set: F/O completes all memory items and does not need confirmation for 'critical items'. Captain communicates with twr/cabin

[de facto]

I typed too fast, yes PM will perform recall items in the air.

In my previous Airline PM was also closing the thrust lever.

By my SOP, CAPT performs recall items on the ground.

[Maurice Chavez]

By my SOP, CAPT performs recall items on the ground.So now the FO assess the situation??? Weird. We stick to Boeing and don't make up our own stuff. RTO done by CAPT, he becomes PF and does not carry out memory items...Like I said, the only thing that is ever done by the PF while carrying out memory items is the handling of the thrust lever. BTW, Boeing has changed from 'Recall Items' to Memory Items quite a while ago. New Boeing SOP's....

[de facto]

Bit sensitive there "memory items" man :ooh::p

[b744FPEK]

listen to your instructors ,so he wouldnt fail you:)


here in my company ,only the captain can call "stop"
and for engine fire ,in our QRH "ENGINE FIRE OR ENGINE SEVERE DAMAGE OR SEPARATION" we only use the second bottle if the engine fire switch was still on after the first one .yes we wait 30 sec.coz its on QRH.
and we will do the EVACUATION after the ENG FIRE QRH. you can not trust the light!
for the memo items.the right seat only do the fire switch . in the FCOM "area of responsibility"the throttle and the eng start lever are all belong to the captain .

and also .before the evacuation ,i would tell the cabin crew to evacuate from the opposite side of the fire.

[rudderrudderrat]

Guys,

I think we are in danger of getting into "simitis" here. It depends on the circumstances.

We have to practice Emergency Evacuation in the sim, and for a realistic scenario sometimes an engine fire warning is included for realism.

If the Engine fire warning is out and the Fire Chief confirms there is no danger - why would you want Evacuate and break a few elderly bones? You always have the option to evacuate some seconds later if it really was required.

[Maurice Chavez]

Bit sensitive there "memory items" man :ooh::pLol, sorry must have gotten carried away... :E

[grounded27]

- firing a bottle does nothing to the fuel supply.

There is no time restriction on firing the second bottle. Evacuation - that is what you are paid to decide.

Actually, I do not know of a modern jet that will allow you to discharge a bottle W/O first pulling the fire handle thus cutting off fuel.

First possibility you should think of is a blown duct, as you reject after engine idle if the warning goes away, fire handle pulled as said before visual confirmation (window,cc or atc). Blow your bottle as you wish and do not panic, confirmed fire may force egress before you blow your 2nd bottle. Good egress communications to cabin depending on nature of fire wind etc..

Teamwork and a good communication with your other crewmember(s) is vital.

[punkalouver]

Parking brake set: F/O completes all memory items and does not need confirmation for 'critical items'.

Is it the same with 'critical items' for other procedures such as ENG FAIL....no confirmation required.

[capngrog]

I'm not a chemist but I was under the impression that the exact opposite was the case: the whole effectiveness of halon-like suppressants comes from their ability to interfere with combustion processes at the atomic level, once broken down by heat. The cooling/smothering effects are welcome but secondary...

See: SKYbrary - Halon Fire Extinguishers (http://www.skybrary.aero/index.php/Halon_Fire_Extinguishers)

That is correct, FullWings. In a previous life, 35+ years ago, I was a fire protection engineer, and your above explanation was the then accepted understanding of Halon's interaction with the combustion process. Lower extinguishing concentrations of Halon are not lethal to Human Beings since Halon is not an atmosphere (oxgen) displacing substance such as is CO2.

Over the years, I've read many accident reports and have noted an all too frequent lack of timely communication of a problem between cockpit crew and cabin crew and vise-versa. It seems that all too often a serious problem that is revealed by looking out a cabin window is not communicated to the cockpit in a timely fashion. This may be a holdover from the "old days" when cabin crew were reluctant to call the cockpit's attention to a problem out of concern of distracting the attention of the cockpit crew. For example, I recall several instances of decompression or slowly falling cabin pressure that actuated the passenger oxygen masks, but the cabin crew never notified the cockpit crew that the masks had dropped. Anyway, hopefully things are improving with the current emphasis on Crew Resource Management (CRM). I think it is indicative that, in the beginning, CRM was Cockpit Resource Management, but people soon realized that both cabin and cockpit crews must work together in an emergency.

As a reminder of how quickly a ground fire can destroy an aircraft, here's a short video of the China Airlines Flt 120 ground fire that destroyed a B-737-800 on the ground at Naha, Airport, Okinawa on 20 August 2007

The link: https://www.youtube.com/watch?v=0lTLBaAtuNM

Grog

P.S. The fire was the result of a fuel tank breach that occurred when a loose bolt, improperly installed during a maintenance procedure, was forced through the web of the forward wing spar upon slat retraction.

[Jim_A]

Careful and methodical use of the evacuation checklist will generally take care of any issues. An evacuation is almost guaranteed to result in some injuries, so some care should be exercised. If Fire/Rescue is on the scene, they probably can give the best advice.

[lomapaseo]

Careful and methodical use of the evacuation checklist will generally take care of any issues. An evacuation is almost guaranteed to result in some injuries, so some care should be exercised. If Fire/Rescue is on the scene, they probably can give the best advice.

Yes they can advise, but only against what is happening outside. Evacuation initiation is left to the pilot and unfortunately sometime also the passengers based on their senses