Boeing 767 Cargo Fire Suppression

[arff]

Hello;

On the B767 (200 or 300 series) when you push the DISCH AGENT 1 button in the cockpit following a cargo fire indication what systems are activated or deactivated ? Does the electrical cargo door opening mechanism affected ?

Thanks.

[Giles Wembley-Hogg]

On our 767s, pushing the FWD ARMED switch arms all cargo fire extinguisher bottles and turns off both recirculation fans. Subsequently pressing the BTL DISCH switch discharges the bottles into the FWD compartment. The books make no mention of the door being affected.

Hope this is of use to you.

G W-H

[bbbaldy]

The cargo fire suppression system's main function is to deal with a fire whilst in the air.
On ground the door would have to function correctly for ground fire crews to deal with the fire.

[mono]

B767 cargo fire extinguishing systems are quite varied. None that I am aware of inhibit or alter in any way the cargo door operation.

Pressing the agent discharge button will do NOTHING unless the FWD or AFT cargo fire switch is first selected. This arms the bottles, closes the respective cargo heat valves, shuts down the recirc fans, sheds galley power aswell as silencing the fire bell. For the AFT cargo the lav galley vent fans are shut down and the packs inhibited from going to high flow mode.

On dual (bottle 1 and 2 discharge) a/c the bottles are fired individually by the crew. (I think these are non ETOPS)

On a/c with a single button, when the discharge button is pressed the first bottle is immediately discharged into the relevant cargo compartment and a 30 minute timer circuit is started after which time the second bottle (and 2A) is discharged into the compartment. Should the a/c land before the 30 minutes has expired then the second bottle will discharge on touchdown.

The extinguishant is halon (bromotriflouromethane) which is heavier than air, so be careful as you open the cargo doors as this will "fall" out. As a note the correct way to revive a person who has been overcome by halon is to invert them as much as possible so the inhaled halon literaly falls out of the lungs.

[aintsaying]

Arff,
The cargo door system is not affected at all, no matter what system/option installed. As mentioned watch out for the 2A bottle coz there is a chance it might not go off on touchdown as it should.