Etops Extra
Etops Extra
Join Date: Jul 2000
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[Guess mode]
Say you are 3 hours (s/e flying time) from your coastal destination, with your alternate very close by. You are past your ETP and your nearest airport is your destination.
Your engine then fails...
Question is, in this state, might you need a little extra gas to make your destination?
[/guess mode]
Say you are 3 hours (s/e flying time) from your coastal destination, with your alternate very close by. You are past your ETP and your nearest airport is your destination.
Your engine then fails...
Question is, in this state, might you need a little extra gas to make your destination?
[/guess mode]
Per Ardua ad Astraeus
Join Date: Mar 2000
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Hi Cough - not quite sure I understand - you should ALWAYS have sufficient fuel for the 'worst case' div (press'n failure) at any point on the ETOPS route, so if your 'dest' is 'nearest' ETOPS alt then you have the fuel? The only 'extra' would be for, as I said, airframe icing or mum etc. At the last ETP you would have had enough fuel to reach either ETOPS alt (including the one near your dest) with press'n failure and you are then closing with that airfield. .
Join Date: Sep 1999
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ETOPS extra is the extra fuel required to ensure that the aircraft can meet the Critical Fuel Scenario.
On my type, the worst case scenario is considered to be a two engine cruise at 10000' following a loss of cabin alt. We have to be able to fly to the en-route alternate (up to 180 minutes away) at 10000' all engines with a reserve.
In practice, twins flying west across the Atlantic will rarely need it as the destination is usually a long way past the equal time point. Hence they will have lots of fuel remaining for the onward flight anyway.
Heading east, if the destination is western Europe, it is likely to be much closer to the ETP, so not as much fuel on board. Thus the need to sometimes carry ETOPS extra so that you can still make the scenario described above.
In very simple terms, if you were flying eastbound to Dublin and using Shannon as your ETOPS alternate, you would be burning a lot more fuel flying 3 hours from your Equal Time Point to Shannon at 10000' than flying 3 hours 20 minutes to Dublin at FL370.
On my type, the worst case scenario is considered to be a two engine cruise at 10000' following a loss of cabin alt. We have to be able to fly to the en-route alternate (up to 180 minutes away) at 10000' all engines with a reserve.
In practice, twins flying west across the Atlantic will rarely need it as the destination is usually a long way past the equal time point. Hence they will have lots of fuel remaining for the onward flight anyway.
Heading east, if the destination is western Europe, it is likely to be much closer to the ETP, so not as much fuel on board. Thus the need to sometimes carry ETOPS extra so that you can still make the scenario described above.
In very simple terms, if you were flying eastbound to Dublin and using Shannon as your ETOPS alternate, you would be burning a lot more fuel flying 3 hours from your Equal Time Point to Shannon at 10000' than flying 3 hours 20 minutes to Dublin at FL370.
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BOAC,
Well, I was half way right!
Having looked at a BUS FCOM on the matter, its the higher of the extra needed to either cover either the s/e or decomp fuel requirement taking into account the failure occurs at the worst point in the flight and you still should be able to hold for 15min and do a g/a to a VFR circuit + extra needed for APU burn + airframe and engine anti ice requirements + anything else thats relevant (MEL?)
Well, it was a guess!
Well, I was half way right!
Having looked at a BUS FCOM on the matter, its the higher of the extra needed to either cover either the s/e or decomp fuel requirement taking into account the failure occurs at the worst point in the flight and you still should be able to hold for 15min and do a g/a to a VFR circuit + extra needed for APU burn + airframe and engine anti ice requirements + anything else thats relevant (MEL?)
Well, it was a guess!
Per Ardua ad Astraeus
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I am quite correctly admonished by 763 jock there - I was away thinking about the 'extra' I would take on ETOPS above that 'Etops Extra' which is, as 763 says, normally automatically added by your Flt Planning system to your PLOG to ensure you meet the worst ETP fuel case. THEN you need to add the extras for icing/mum etc.
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We used to see ETOPS extra on our flight plans from time to time. It might have been about 1500 kgs, depending on the day. Now the price of fuel is so high, the planners will try to find a suitable set of ERA's that avoid us having to cart the stuff around.
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It's Actually to do with your ETOPS Rule distance. Basically, if you declare 180 mins ETOPs, you have to carry 180mins of fuel from your CP. Sometimes you can reduce your ETOPs Extra by having a flight plan for a lesser rule time. If you take a northern Route from the UK to JFK, for example, you may be able to satisfy a 60 mins or almost certainly 120mins ETOPs rule time distance. Thus you can load less fuel and save some dosh!
Bob.
Bob.
