Do you really have enough fuel? / B737 performance question.

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Thanks for the replies.

Sorry BOAC but I think the answer to your question is no.

I haven't mentioned mutiple failures. I don't consider weather at destination below landing minima a "disaster" at all, especially if it was already forecast to be below the minima and you already planned to carry diversion fuel.

It is simply a matter of identifying, before departure, the most critical point to suffer an engine failure or cabin depressurisation and then calculating how much fuel it would take to enable the flight to proceed from that point to an aerodrome that you (or the company) consider usable.

Sure if while enroute the destination weather suddenly and without notice, reduces below Alternate or Landing Minima (or what ever it is that triggers a change in your fuel requirements) and you've passed your PNR or CP then that's when you'd say you're having one of THOSE moments!

All I'm saying is that I reckon in those cases when the destination requires an alternate, the most critical point to suffer an engine failure or cabin pressurisation failure is during a missed approach overhead the destination.

I was hoping someone might have some data that compares two engine diversion fuel burn with engine out diversion fuel burn for the B737. Perhaps B767 or B777 or even twin engine Airbus drivers might have some idea of the comparison.

John I don't think my company (or many others from what I've gleened here) have identified this as an issue. Actually I tell a lie. The company policy is to not pass that enroute CP unless the destination weather comes good. But if that is the case, why bother carrying diversion fuel? Why not take it that extra step and put on the extra fuel and then all eventualities will be covered, the regulations will have been complied with, and everyone is happy.

So yes when I have faced this scenario during the flight planning an have made that decision to put on the extra fuel. But the amount has been nothing more than an educated guess based on the enroute figures I mentioned in my earlier post. I know I could do better if I had the information I am seeking.

Cheers.