737NG Cargo Fire management

[framer]

Hi,
If you have had an indication of a cargo fire and carried out the checklist airborne, and after landing neither the Fire Rescue folk or the Cabin Crew can find evidence of smoke or fire, would you taxi the aircraft to the terminal aero bridge or disembark using stairs away from the building?
I think I would have the fire trucks escort me to a normal bridge as I can imagine the stairs taking some time to arrive but I would appreciate anyone else's thoughts or experiences with this.

[Intruder]

What does your QRH non-normal checklist say? Ours (744) says not to open any cargo door until all personnel have exited the airplane. How you you know there is no fire? maybe there was/IS a fire, and the fire suppression system is [for now] successfully doing its job.

Which option carries the least risk of injury to the passengers?

A long taxi followed by a normal exit would probably not be a good idea, but an evacuation also carries risks.

I would suggest that taxiing off the runway and evacuating on a nearby, clear area of the ramp or taxiway would be prudent. If a fire DOES flare up when the cargo door is opened, do you want to be at the terminal?

[framer]

The best the QRH gives is Warning! Inform ground personnel NOT to open any cargo door after landing until all passengers and crew have exited the aircraft and fire fighting equipment is nearby
That information would already have been passed to ground staff prior to landing most likely, and probably reiterated after landing.
Which option carries the least risk of injury to the passengers?
That is the crux of it isn't it. I'm picturing three options , 1/ a three minutes taxi onto stand with a normal disembarkation 2/ An evacuation and 3/ holding off the bay and getting stairs brought to the aircraft. Options 1 and 3 are able to be upgraded to evacuation.
The premise of the scenario is that neither Fire Service or cabin crew have noticed anything unusual.
Thanks for your opinion, food for thought.

[Capt Chambo]

I know the Boeing 737NG manuals mix and matches the phrase "cargo fire" and "cargo smoke" throughout them. There is no heat/fire detection in the cargo holds (unless it's an option that I haven't come across) it's purely a smoke detection system, which can be "fooled" by anything that might reduce visibility across the sensors.

How does your company deal with fire/smoke indications? Always treat them as real?

If the ARFF have thermal imaging cameras they may be able to advise you whether or not they are picking up a heat signal.

In your scenario, I think I would be inclined to do as you say, taxi to an aerobridge with the firetrucks following behind. The other thought I have, would be to request/demand a pier that has good access for the ARFF. I note your location as Sydney, so I wouldn't want to end up down the bottom of a cul-de-sac, I would want an aerobridge either at the end of a pier, or if possible one with adjacent aerobridges clear. The ARFF/Sydney Airport owners/operators/your company may of course have other ideas, but an aerobridge at the front, steps at the back and a precautionary disembarkation would be something I would consider.

And of course make sure the ARFF don't open any holds/E&E bays until all the passengers and crew are off!

[Kefuddle]

Framer,
If you have had an indication of a cargo fire and carried out the checklist airborne, and after landing neither the Fire Rescue folk or the Cabin Crew can find evidence of smoke or fire, would you taxi the aircraft to the terminal aero bridge or disembark using stairs away from the building?
Hmm. Given that I have no idea how to assess if the cargo fire indication is real or not as I don't know how high temperatures in the either compartment (737) would or could be sensed reliably by the crew or passengers.

We have an added complication in that we have no procedure for a precautionary disembarkation without stairs. Leaving only a full blown evacuation as the injuries that go with it. Any attempt to try and organise an orderly disembarkation with the slides just runs the risk of creating confusion with no clear trigger as to when that should be escalated.

I would not take the aircraft to a jet bridge, a remote stand could be a possibility but then additional coordination, delay and communication issues with regard to placement of stairs is an issue, and without knowing how to quantify the situation how could I find that acceptable?

I'm afraid, I would stop the aircraft. Use standard cabin calls and evacuate. Then face the music and dance.

[cosmo kramer]

I'm afraid, I would stop the aircraft. Use standard cabin calls and evacuate. Then face the music and dance.

For an unconfirmed fire indication? Think about the risk that someone might get seriously injured during the evacuation.

Cargo smoke detection and fire suppression didn't become mandatory until recently. A lot of aircrafts are still flying without these systems and that include modern aircrafts like early 737NGs. At my previous employer most of the aircrafts didn't have it.

Would you taxi the aircraft to the terminal aero bridge or disembark using stairs away from the building?
I don't think you will be able to make that decision. With high probability the airport have their own procedures for such situation. And if in a civilized part of the world, I am sure you will have stairs in the blink of an eye.

[Kefuddle]

For an unconfirmed fire indication?For one that won't appear to extinguish - as I made it clear, that I would not know how to confirm nor quantify it. Perhaps you have some training or knowledge in that area? Perhaps some common sense systems knowledge I have managed to bypass? I'm certainly open to suggestions to guarantee safety of all on board and avoid unnecessary injury.

Think about the risk that someone might get seriously injured during the evacuation.
Yup, almost certain to happen and already noted.

Cargo smoke detection and fire suppression didn't become mandatory until recently. A lot of aircrafts are still flying without these systems and that include modern aircrafts like early 737NGs. At my previous employer most of the aircrafts didn't have it.Interesting. But then surely you don't know, you can only work with the information you have. Anyway, the equipment fit on other aircraft is not relevant to the decision making process.

[PENKO]

Keffudle, I would not evacuate based on a warning light, if there are no other signs of fire. You know that it might be overripe fruit or a burst can of deodorant causing the warning. I sure as hell would declare an emergency and land ASAP. But once on the ground and still in tact, I would want more signs of a fire (which would have been raging for more than 20 minutes!), before I evacuate. On the other hand, I would NOT park anywhere near a terminal until cleared by the fire fighters.

You ask for signs of fire...well...the ABSENCE of any further signs is a sign. :ok:
If the cargo hold is so well insulated that you don't see any signs after 20 minutes of fire, then you might as well wait for steps. Just my humble, untrained in firefighting, opinion.

Regarding the evacuation itself, I'm not entirely sure that it's such a mortal danger on a lowish 737.

[cosmo kramer]

Regarding the evacuation itself, I'm not entirely sure that it's such a mortal danger on a lowish 737.
Then you didn't see some of our passengers. Looking at them, you would think they would die falling off a chair! :}

Otherwise, everything you said. :ok:

[Kefuddle]

You ask for signs of fire...well...the ABSENCE of any further signs is a sign. :ok:
Well yeah obviously, but the cargo compartments of a 737 are sealed. What specifically, from the cabin or flight deck, would you use to determine if there is or isn't a fire to go with the flight deck fire warning?

How long before signs of fire are evident? Ten, perhaps twenty minutes? Perhaps five minutes before mass panic ensures serious injury or fatalities.

If you decide to taxi to a stand, get the stairs and disembark, statistics are probably in your favor as all cargo fire incidents that I am personally aware of have been false alarms. But that isn't really a factor for consideration as far as I am concerned.

Anyway, there's my case. Just make a decision and deal with it :)

[cosmo kramer]

What specifically, from the cabin or flight deck, would you use to determine if there is or isn't a fire to go with the flight deck fire warning?
Hot cabin floors, having the fire fighters feeling the cargo door (in lack of thermal equipment). An immediate evacuation, for what might be a simple sensor failure, might be a bit over the top.

[PENKO]

Well yeah obviously, but the cargo compartments of a 737 are sealed. What specifically, from the cabin or flight deck, would you use to determine if there is or isn't a fire to go with the flight deck fire warning?

I would have been in constant contact with the cabin crew. Any smoke? Any heat? Any odors or fumes, strange sounds? The usual. You will never be sure wether there is a fire or not! But what you can say is that the 'supposed' fire has had zero consequence up till now. Why dismiss that crucial piece of information?


How long before signs of fire are evident? Ten, perhaps twenty minutes? Perhaps five minutes before mass panic ensures serious injury or fatalities.
You should ask yourself why you did not make a forced landing in a corn field and reason on from that point. You are constantly assessing risk and probability. If you deemed yourself safe enough to fly all the way to an airport, then why 'panic' at the last moment, whilst everything else tells you that you are probably not on fire?

If you decide to taxi to a stand, get the stairs and disembark, statistics are probably in your favor as all cargo fire incidents that I am personally aware of have been false alarms. But that isn't really a factor for consideration as far as I am concerned.
At some point a false alarm HAS to be a consideration. If not for the pax you just evacuated, then for the firemen you put in charge of opening the hold (in stead of axing a hole in your plane). Will you take responsibility for that?

Anyway, there's my case. Just make a decision and deal with it
Interesting to see your case.

[Kefuddle]

having the fire fighters feeling the cargo door (in lack of thermal equipment)Yes, I can see that it would probably be prudent to hold on for an exterior inspection. But I would probably prefer not to taxi anywhere, but stop the aircraft, alert the cabin and simply standby to give the best chance of an incident free evac should it then become necessary. But I'm considering a fire would have already caused significant internal damage for anybody to sense anything significantly unusual from the cabin.

However, the only cargo fire warning event we have had involved the crew taxing to a stand and then the fire crew spontaneously opening the cargo door with the pax on board before declaring the all clear! Not suggesting that is in anyway representative, but if there were a fire...

[RAT 5]

There are various points made about this 'grey' area of decision making. The thread start question was "you HAD an indication of a fire…" From this I assume the cargo fire extinguisher was fired and the fire light went out. All the comments about evacuation or disembarkation seem to assume there is still a fire. Why do they assume this? Take care, of course, but what do you really expect? In the case of earlier generation types of B737, DC9, MDXX's etc. there was no fire detection or extinguishent. The hold design was such that it burnt itself out without fuselage damage, in theory. You would pull onto stand none the wiser.
Now there is some indication and it would be prudent, if the warning was out, to alert the fire boys and have them standing by for the cargo hold opening. But again, what do you expect? If the fire warning is out, and the hold is designed to burn the O2 to suffocation without damage, which = 2 kinds of extinguishent, why not believe it? OK, there are those who believe it is always a case of hope for the best and plan for the worst. In some cases, true, but it would be debilitating if applied to many aspects of life. It would be an interesting court case to chuck all the pax out, have injury claims because they claimed there was no need and it was a panic measure. What would the defence be? A lawyers field day. Ask 100 captains and get 200 opinions.

[framer]

Regarding the evacuation itself, I'm not entirely sure that it's such a mortal danger on a lowish 737.
I've read an incident report of an RTO followed by evacuation in Ireland on a 737 where one lady broke her neck going down the slide and several others had very serious injuries. The main issue was people piling up at the bottom of the slide.
From this I assume the cargo fire extinguisher was fired and the fire light went out
Seeing as there is no heat detection, only particulate matter detection, and Halon levels are being kept above 5% for the first 60 minutes, would the light go out? I have had a cargo fire warning on the ground from a disinsection spray can being let off before a ferry flight.....would Halon be any different?

[RAT 5]

Seeing as there is no heat detection, only particulate matter detection, and Halon levels are being kept above 5% for the first 60 minutes, would the light go out?

I can not answer this question, but I'd be rather nervous & surprised if they designed a system where the fire extinguisher was fired, the fire went out but the fire warning didn't indicate this. Imagine such a scenario on a 180min ETOPS sector. Have I misunderstood your comment.

[framer]

No you understood.
I imagine that you are correct but I don't know for sure.
If a disinsection spray can sets it off, why not the Halon?

[cosmo kramer]

From this I assume the cargo fire extinguisher was fired and the fire light went out. All the comments about evacuation or disembarkation seem to assume there is still a fire. Why do they assume this?

I can not answer this question, but I'd be rather nervous & surprised if they designed a system where the fire extinguisher was fired, the fire went out but the fire warning didn't indicate this.

The cargo compartment fire warning, warns you of SMOKE - not a fire. So even if the fire causing the smoke can be suppressed with halon, the smoke would likely still be present.

[Kenny]

According to the Fireys at YSSY, what they'll do is use heat-thermal cameras to gauge the heat of any area that has had a suspected fire and if they feel that there's further risk of a fire within the cargo bay, they'll drive up, stick a probe through the cargo door and fire in more extinguishing agent.

[Kefuddle]

If a disinsection spray can sets it off, why not the Halon? The spray is definitely particulate with a visible mist the lingers. Halon BCF, as far as I am aware, is just a gas.

The cargo compartment fire warning, warns you of SMOKE - not a fire. So even if the fire causing the smoke can be suppressed with halon, the smoke would likely still be present. Excellent point. As a twist, if the cargo fire alarm does activate, given that the compartments are sealed, should we not actually expect the warning to continue? If that is the case, then if the warning does go out, could it be possible that the smoke detector has been destroyed due to a still raging fire?

[framer]

should we not actually expect the warning to continue?
That is my point/ question.