Time to dispel a few myths!
The leak detection process has not changed, you simply add the fuel used to the fuel on board and it should equal the fuel you started with, same as any other aeroplane. An additional indication may be increased fuel flow if the leak is down stream of the fuel metering unit. You will also see your arrival fuel decrease on the FMGC; this was always the case nothing has changed.
The only change to the procedures I am aware of post this incident is to further highlight the correct actions following a fuel imbalance. You were then and are now required to check there is not a leak before you open the fuel cross feed using the above method just as we did on the MD and Boeing aircraft! Using the KISS principle for leak detection seems a good idea to me!
There was a long standing blue bulletin that highlighted this procedure which has been incorporated into our SOP’s. This bulletin recommended a check (fuel used + fuel on board = fuel you started with) at least every 30 minutes and was effective at the time of this incident. This check takes just a few seconds even a 4 o’clock in the morning!
The TV program alluded to software changes to alert crews to a fuel leak; if there have been any its news to me.
The indications of a leak will be as follows and in this order:
1: A fuel imbalance ECAM drill
2: Fuel low level ECAM drill
3: Engine flame out.
The engine flame out may occur before the tank runs dry if the leak is from the engine depending where in the engine the leak is. If the fuel cross feed is opened then you will get fuel low level indication in the non-leaking tank and then another flame out, on the plus side at this stage you no longer have a fuel imbalance.
The oil pressure/temp problem was due to the location of the leak and the cooling effect of the leaking cold fuel. This would have confused the crew no doubt about that as there was no way for them to know this at the time but to be honest I feel this is a red herring as the crew clearly carried out the fuel imbalance drill but failed to establish if there was a leak before opening the cross feed. It has been suggested that the ECAM misled the crew due to prioritising and oil problem ahead of the imbalance drill, yet the crew clearly carried out the imbalance drill all be it incorrectly.
I would not claim the Airbus systems are perfect, far from it, you must always be aware of the system limitations especially when it comes to ECAM. However in this case I can find little excuse for the crew opening fuel cross feed and then leaving it open when logic was screaming fuel leak. This was not a failure of the system but of its operation following a mechanical failure brought on by poor maintenance procedures.
Bottom line, the crew failed to follow established procedures!Unless further evidence comes to light to account for their actions one has to lay a large amount of responsibility for the engines flaming out at their door.
