A320 Generator MEL

[MD83FO]

Good Morning,

Any Ideas why the MEL limits to FL335 on Gen Inop dispatch?
Thanks.

[Ollie Onion]

I seem to recall that it has something to do with the APU generator. The APU generator is required to run throughout the flight and I am pretty certain that above FL335 there is a risk of 'arching' in the APU GEN. That may not be correct as I am reaching way back in the old brain to come up with that.

[WhyByFlier]

The limitation is to ensure that you have 100% of the APU output available. If you go to FCOM LIM 49-20 P1/4 at the bottom of the page there is a table containing generator loads in flight for different levels. There you will see at ISA and 35000 Feet you only have 93% or 84 KVA available.

[100.above]

If you draw a line on the graph as well you will see that FL335 gives you 90kvA at approx ISA + 23 or so. So this would cater for most environments

[MD83FO]

got it, thanks guys.