Cargo Hold Fire

[woofer]

I would greatly appreciate any thoughts and feedback with regards to the following scenarios. My technical knowledge is confined to the Boeing 737, but I guess it applies to any Boeing fleet.
Shortly after takeoff we get a Foward or Aft Cargo fire alarm with the associated light. We follow the checklist and discharge the bottle in the appropriate hold. My first question is:
If we manage to put out the fire, does the 'Cargo Fire Warning Light' extinguish?
I am almost certain that it does go out but I can't find evidance supporting this in the flight operations manual.
Since we can't physically verify whether the fire has really been extinguished, should we still return back for landing?
The checklist states that we should plan to land at the nearest suitable airport, so in my opinion we should turn back, vacate the runway and disembark the passengers using steps.
Now let us assume that the light does not extinguish, we declare a Mayday emergency, squak 7700 and request vectors back to the airport. My other question is:
After landing and stopping on the runway, we receive feedback from the fire fighters (since many have their own frequency) or tower that they can't see any fire or smoke coming from the cargo hold door, should we still order an evacuation using slides? (Don't know if smoke can be seen given that the doors should be sealed)
I would still order an evacuation using the slides even though people can get hurt during a slide evacuation. Better safe than sorry I guess.
Thanks for any feedback you can all provide

[john_tullamarine]

Regarding landing, and given that any fire is probably the most threatening of likely emergencies, .. once the bottle(s) is(are) fired, then there is nothing else left to use in the event that the fire starts up again ? I suggest that one would need a good reason NOT to divert to the nearest appropriate airfield following any bottle discharge as the departure extinguishant redundancy has just evaporated with the extinguishant ....

[Intruder]

A cargo hold fire is an immediate and dire emergency. Land and evacuate.

While the fire bottle may suppress the fire immediately, there is no guarantee the fire will not flash again when doors and/or outflow valves open or the fire suppressant runs out.

[Rainboe]

Every emergency evacuation causes at least one serious injury and several minor ones. If one landed and all was apparently OK, what is the panel's verdict on taxiing to a clear area where steps have been positioned and warning the cabin crew to watch for any signs of conflagration and report back, but just sit on your thumbs and disembark on the stairs? I say this because of the multitude of false cargo hold fire warnings there have been and the incredibly small number of genuine fires. Maybe worth thinking about- say 9 precautionary evacuations with many injuries v 1 genuine fire (that kills 'em all anyway before they can get out)

[ILS Repeater]

Your company SOPs should state that following the discharging of any fire suppressant, you should land at the nearst suitable airport/airfield. The QRH for our Boeing fleet states land at a suitable airfield within 60 minutes of extigusher discharge. For aircraft fitte with a Class D type fire supressant system, it further states, you sould also attemp to agitate the extingusher gasses by altering the pitch an yaw to effect a more even spread of fire suppressant !

[tired]

Really good thread this - something we all hope won't happen to us, but which we should think about nonetheless.

I tend to lean towards Rainboe's way of thinking on this one - if, once you've landed there's no obvious signs of smoke/fire then it might be a good idea to at least start the disembarkation via steps - if they're readily available. But it requires good, clear comms with the fire crew and with the cabin crew because you might have to evacuate in a hurry halfway through the disembarkation. So you need to leave all the doors in armed and guarded by cabin crew, except the ones that the steps are at, and the troops need to be aware that it might become necessary to blow the slides and jump out at any time. You need clear comms with the fire crew outside, and you need to make sure that the cabin crew are monitoring inside - though I suspect they'd be doing that without being told!

Like most things in aviation I think it depends on the situation on the day, and it certainly depends on which airfield you're at - whether they can produce steps PDQ, what you think of the competence of their fire crew and how well you can communicate with them. If in doubt I guess it's better to risk injuries in a needless evacuation rather than risk deaths from getting caught in the fire.

Something that's been alluded to in previous posts, but which might be worth repeating clearly - if you think there might be a fire in the hold don't under any circumstances open it, or allow the fire crew to open it (those "good comms" again!) until everyone is off the aeroplane. The chances of a flashover occuring are huge.

t