Isolated Aerodromes!

[capt_d]

Hello, Gents!
I was wondering about EASAs definition of an isolated aerodrome. From one hand in CAT.OP.MPA.106 is written that:

An isolated aerodrome is one for which the alternate and final fuel reserve required to the nearest adequate destination alternate aerodrome is more than:
for aeroplanes with turbine engines, fuel to fly for two hours at normal cruise consumption above the destination aerodrome, including final reserve fuel.

But from the other hand in SOP.OP.105
For the selection of alternate aerodromes and the fuel policy, the operator shall consider an aerodrome as an isolated aerodrome if the flying time to the nearest adequate destination alternate
aerodrome is more than:
(b) for aeroplanes with turbine engines, 90 minutes.

How to understand this? Does this 90 min are a result of 2 hours above destination at cruise consumption minus 30 min of final reserve?

[AerocatS2A]

Definition 1: Isolated is if the nearest alternate requires 2 hours of fuel including fixed reserves (30 minutes)

Definition 2: Isolated is if the nearest alternate requires 90 minutes of fuel not including fixed reserves.

Both definitions are the same, it's just that the first one includes reserves and the second one doesn't.

[Driver 170]

But why would you consider without Reserve Fuel

[AerocatS2A]

You don't. It is just defining a remote airfield. Both definitions are the same but worded differently. They both define a remote airfield as being one that is more than 90 minutes from an alternate.

[TRICAM]

So if I am flying to a destination with an alternate 1hr 40min away, with sufficient fuel to that alternate I have to consider that destination as isolated.

I never thought about it that way. During winter in Russia this has happened a lot and I was not aware of it.... Thanks guys!

[Greyhame]

normal cruise consumption = in still air?

Kr