"...if after 30 seconds....discharge...."
 

Many Engine Fire cklists call for the second bottle to be discharged after 30 seconds.
But from what?
The moment I have cut the fuel, or the moment I discharge the first bottle?
Personally I think this is a purely academic question, but some people are surprisingly picky on that!
:8

Airbus FCOM 3/ ABNORMAL AND EMERGENCY/FIRE PROTECTION/ENG # FIRE IN FLIGHT:
"Discharge the second agent, if the fire warning remains 30 secs after the discharge of the first agent"

Well heres my 2 pennys worth.

I would rotate the fire handle and hold for 1 sec as stated in the QRH and then start my clock and await the 30 sec before discharging the other bottle if needed........

:uhoh:

Sonia

From KLM 737 Emergency Checklist:

".... rotate to the stop and hold for one second " first discharge

"If after 30 seconds the Engine Fire Warning Switch or Engine Overheat light remains illuminated:
Engine Fire Warning Switch.............Rotate to Remaining bottle"

So... as others have also stated here: rotate to first bottle, hold for one second and start timing. If all hasn't gone quiet and dark by then shoot the second bottle. If on the ground you can then time for thirty seconds again and if nothing has happened by then evacuation would be the next option. Obviously in the air this option would not be directly available which leads us to your other topic concerning emergency descents.

The Airbus ECAM counts down 30secs for you after you have fired the first bottle. Nice and easy.

Quite obvious. But on the ground I would think of firing both bottles into one engine inside the 30 sec. Cos it will not do any further damage and you're making damned sure that the fire can't keep raging on.
In the air it's a different matter....

Quite agree, the Airbus (and Boeing I would think) drill for eng. fire on the ground says fire both bottles straight away. If it does not go out pretty fast you are going to evacuate anyway so you might as well give it both shots.

Intersting!
Confirm Airbus calls for firing BOTH bottles with no delay on the ground?

ARFF / Pilot communication
 

While on the ground, and with an engine fire warning on, what kind of information specifically will you be requesting from the ARFF commander ? (visible flames, smoke, etc...).

Seems to be sensible, that Boeing prescribes the same medicine...

ARFF- No disrespect to you guys and girls, but I think by the time we had contact with you and you were near enough to see anything, our decision to evacuate would have been long taken. If we are still there when you arrive, anything you can tell us. Certainly any signs of fire.

LEM - certainly no delay - there is NO point in waiting. In the air, it is wise not to fire a bottle unless you need to, hence the pause to see if the first one works.

I totally agree with the post made by BOAC :)

It does happen!

For those who wish to be REALLY picky and pedantic, the 30 seconds should start from the INDICATION of DISCHARGE - depending on type, that could take a second or so after actvation. So, pop the switch, wait for the discharge light, start timing....... should keep even the 'sim' guys happy!;)

BOAC, the point in waiting is the official 737 cklist which calls for 30 seconds delay in the air AND ON THE GROUND.
But I agree with you it would be better to disregard those 30 " on the ground. The problem is that any deviation exposes you to criticism....

Any action you'll take will get criticism anyway.
I do sincerely think that you'll get a pat on the back anyway if
the engine hasn't burned down its socks.
It isn't a strange rationale right to fire both bottles into the engine after a sensible delay to see if it has worked or not....
Who can tell you not to do so for doing that?

LEM
 

Typical Boeing QRH NNCHL:
Engine fire switch................................ override, pull, rotate
........
"If after ... seconds ENGINE FIRE LIGHT REMAINS ILLUMINATED..."
No elaboration, easy. Done like dis at d sim all d time...
Cheers,

LEM - I cannot find a reference to 'wait 30 seconds' in the cklist we use - it says discharge both bottles into the engine in question. What is the EXACT wording of your evac cklist regarding bottles?

ON THE GROUND:
Once again le good ol'e AIRBUS FCOM:
"- AGENT 1 + 2 ....................DISCH"

Shaka, I don't agree with you: you are exposed to criticism only if you deviate from the established procedure, unless there is a good reason to do so.
Of course you'll get a pat on your back if all ends well!!!
But our scenario calls for a fire NOT extinguishing!
If after evacuation the airplane burns out, they will reproach to you the fact you have discharged both bottles without waiting the famous 30 seconds.

Swish 266, exactly as you say, IF AFTER 30 SECONDS the fire remains, discharge the 2nd bottle.

BOAC, exact wording for ENGINE FIRE, SEVERE DAMAGE OR SEPARATION (Classic):

"... IF after 30 seconds the Fire Warning LIght remains illuminated:
ENGINE FIRE WARNING SWITCH...ROTATE TO REMAINING BOTTLE..."
No difference between in flight and on ground procedure.
My manuals could be obsolete, could anybody else check if this wording is still valid (737 classic)?

:{

Thank you Bik, so the 30 seconds are confirmed.;)