EDTO planning
Thread Starter
Joined: Nov 2010
Posts: 161
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From: N/A
EDTO planning
When preparing an OFP for a transatlantic flight that includes EDTO, the critical fuel scenarios (OEI, depressurization, or both) are always considered. However, should the dispatcher also account for other aircraft limitations when selecting an EDTO alternate? For example, if a dual hydraulic failure limits max crosswind to 15 knots, does this need to be factored in when choosing an alternate, or is it outside the dispatch planning scope?
Joined: Aug 2009
Aviation Qualifications: ATPL
Posts: 616
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From: GPS L INVALID
EDTO rules are pretty specific, there are some traps to consider. A nice example I've personally seen was a flight to eastern China from Europe, there's a fair amount of high terrrain around the airport of Urumqi (which is usually a conventient intermediate alternate). That airport was closed by NOTAM, so the dispatchers planned an ETOPS segment with the ETP located very near to Urumqi. Here's the issue - its towards the end of the flight, and the diversion scenarios usually require more fuel than you have left at this point - so additional fuel is required. Now - because of the terrain, at least my company has escape routes that lead you out of this area, but those are much longer than the 'direct to' diversions which are considered for ETOPS/EDTO. You end up with a flight plan which barely accounts for 'direct to' diversions at FL100 to the next alternates, but in reality unfortunately there is a lot of granite in your way if you try to fly this.
Only half a speed-brake
Joined: Apr 2003
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From: Commuting not home
1400 NM from ZWWW to "east China". Hard to imagine that remaining trip fuel would be insufficient to cover the ground to ETOPS altn. Almaty (non-direct), Karaganda, Lanzhou... but indeed that part of globe makes you feel lonesome.
I mean no disrespect to the value of the exercise presented; just that this particular example is hard to replicate.
I mean no disrespect to the value of the exercise presented; just that this particular example is hard to replicate.
Joined: Jun 2008
Posts: 80
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From: Some hotel
When preparing an OFP for a transatlantic flight that includes EDTO, the critical fuel scenarios (OEI, depressurization, or both) are always considered. However, should the dispatcher also account for other aircraft limitations when selecting an EDTO alternate? For example, if a dual hydraulic failure limits max crosswind to 15 knots, does this need to be factored in when choosing an alternate, or is it outside the dispatch planning scope?
