A question for multi-engine drivers

[Boac]

Apologies to those who are not such, but may I ask those who are current or recently retired multi-jet pilots for their opinions?

The report on the BA 777 at Las Vegas is published, and leaving aside any 'mistakes' made by the crew, I would like to address the increasing number of events where an engine disintegrates and bits damage the airframe, in particular during take-off.

It seems that a major factor in the fire intensity was the pooling of burning fuel under the damaged engine. This sort of leak, caused by penetration of the fuel line to the engine by the damaged parts, is not contained until the spar valve or similar is shut off as part of the fire drill. This could be some time after the aircraft has stopped - several seconds, during which more fuel is feeding the burning pool of fuel.

My query is, should we change the abort procedure where engine damge or fire is experienced to call for the shut-off of fuel to occur much earlier, say during the last few knots of the abort? This would be a directed and UN-MONITORED action by PNF and should not affect the ability of PF to bring the aircraft safely to a halt. On the Boeing 737, this would be achieved by step 3 of the engine fire drill, the fire lever being pulled. In the 'normal' world this does not happen until the aircraft has been stopped on the runway (nd normally the parking brake set) by which time the fuel leak is into any fire. Can our 'ace' pilots come up with objections/issues to a change in philosophy?

[om15]

To gain high power ground run authorisation on the A300B4 I had to carry out runs in the sim, part of the fire drill was to manually shut off the airframe fuel cock (using the fire handle) and note just how long the engine carried on running before it spooled down, I can't remember the exact time but it seemed to be a minute or so. It definitely is not an instant event and we were briefed to be aware of this.
Smaller engines fitted to the Citations (PWC JT15D ) had a device fitted at the rear of the turbine, in the event of an engine failure the turbine moved rearwards a few thousandths of an inch and tripped this mechanical lever, shut the fuel to the engine instantly.

[boing]

Basically the wing of an airliner is a big fuel tank, it may be divided into actual individual tanks but almost every cubic foot of the wing contains fuel.

The problem is not that the excess fuel gets to the ground via the fuel shut off system it is that the tanks have been pierced by the shrapnel of the engine break-up and they are leaking like sieves. Shutting off the fuel is important in the case of an engine fire and it is a necessary action in the case of an engine break-up but if the tanks are pierced activating the fuel shut-off may not help much.

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[Boac]

All agreed, but would we lose anything and maybe sometimes gain something?