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Non-ETOPS/EDTO diversion planning

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Non-ETOPS/EDTO diversion planning

Old 11th May 2016, 10:20
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Non-ETOPS/EDTO diversion planning

As the title says, I'm looking for some info on diversion planning pre-dispatch for non-ETOP/EDTO flights.

As an example flight, SYD to HKG in a 777 has numerous adequate airports within 60 min, so only normal fuel calculations apply. Most regs require the depress and OEI scenarios also be planned, with the highest fuel of the three taken.

Obviously to avoid taking unnecessary extra fuel, the depress & OEI scenarios are planned based on additional airports along the route, as looking solely at SYD and HKG would require loading extra fuel, most likely for a depress at the depress crit point.

Logical safe thinking/airman-ship aside, is there any additional requirements such as monitoring or weather minimums that become applicable to the airports used to calculate these scenarios, even though they are not officially designated 'alternates' of any kind, and are just used to show fuel planning compliance?

Also do these airports, and their respective depress/OEI crit points need to be provided to the crew? I don't imagine flying in NA or Europe where adequate airports are everywhere this would be the case, even though the calculations still have to be made. If not, do dispatch keep a record of how this was calculated for any future audit/incident investigation?

I have heard 3rd hand that QF provide info (airports, fuel required, diversion time etc) used to calculate the most critical depress and OEI crit points only on flights longer than 1000nm.

I understand that each operator may handle this differently so I may get a number of different responses, but any additional info would be greatly appreciated.
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Old 11th May 2016, 11:04
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I fly this route frequently in an A330 and we use ETOPS180. Not as many suitable airports for a widebody as one might think... I don't know what other airlines do (I'm not QF, nor CX)

A better example for your question would be eg. S.E. Asia - India. It's a non-ETOPS longhaul flight with numerous enroute alternates listed.

Technically, ETOPS scenarios don't have to be applied to these alternates, as this is a non-ETOPS segment. However my airline still assumes the most penalizing scenario (normally single eng decompression).

Even so, enroute diversion fuel is seldom (if ever) critical. Since the enroute alternates are close-by (within 1 hr), I'd expect the fuel to destination + dest altn + reserves to be more than enroute diversion fuel. Therefore, no extra fuel required.

The only time I see extra fuel due to enroute requirements are eg. ETOPS flights from Asia to Hawaii. HNL is the destination and an ETOPS alternate at the same time. So there must be enough fuel to reach HNL from the critical point (which is 3 hrs away) on single engine and after decompression. That's 3 hrs s.e. cruise at FL100, so it is normally more penalizing than normal flight to dest+altn+reserves.

As for the second part of your question - yes, the enroute alternates are listed on the CFP, even on non-ETOPS flights. For flights less than 2 hours, origin and destination are normally sufficient (weather permitting), since you're always within 1 hour from either of them. For longer flights, an intermediate alternate has to be designated, with adequate wx. When I was flying in Europe, it was the same. Even though there were zillion airports fulfilling the requirements, one of them had to be officially designated as enroute alternate for dispatch. Of course it was more of a paper exercise - once you were airborne you could land anywhere...

Last edited by C_Star; 11th May 2016 at 11:20.
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Old 11th May 2016, 13:28
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Thanks for the reply C Star.

My experience so far is only in long haul and ETOPS ops, as I toiled away in GA prior, hence my questions. Where I work now we operate our medium-long haul flights much the same in that they are always ETOPS flights, regardless of the presence of numerous adequate airports within 60 min.

I have however observed a regional Asian flight of about 4 hours. The CFP didn't contain any enroute alternates and no crit point info was included. I assume additional airports were used to calculate the depress and OEI fuel scenarios as without you'd be looking at about 2 hours depress. Unless of course I'm wrong and the departure and destination did cover all scenarios. I just found it interesting there was nothing published regarding diversion calculations.
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