Equal Time Points
Join Date: Sep 1999
Location: Geneva, Switzerland
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There is no hard and fixed rule on the number of ETP's you would present to any given route. The number of ETP's is directly related to the number of ETOP's alternates required for the sector in question and the number of ETOP's alternates directly relates to your ETOP's certification.
For example. (Great Circle routes used)
London to New York (on a 120 minute certification) would require 3 ETOP's alternates, EINN, BIKF & CYQX. If I was dispatching it, which is unlikely at the moment, I would be providing ETP's for at least EINN/BIKF, BIKF/CYQX and EINN/CYQX.
For a more southerly routing, for example London to Montego Bay, you would need 4 alternates EINN, LPLA, CYQX and TXKF. ETP's would be provided for EINN/LPLA, LPLA/CYQX, CYQX/TXKF, TXKF/MKJS.
Moving even further to the south, London to Barbados gets a bit more tricky and would probably need 180 minutes certification or (and preferably) at least another engine!!
Common sense is the key to good dispatch practice.
Whooaahh!!!
For example. (Great Circle routes used)
London to New York (on a 120 minute certification) would require 3 ETOP's alternates, EINN, BIKF & CYQX. If I was dispatching it, which is unlikely at the moment, I would be providing ETP's for at least EINN/BIKF, BIKF/CYQX and EINN/CYQX.
For a more southerly routing, for example London to Montego Bay, you would need 4 alternates EINN, LPLA, CYQX and TXKF. ETP's would be provided for EINN/LPLA, LPLA/CYQX, CYQX/TXKF, TXKF/MKJS.
Moving even further to the south, London to Barbados gets a bit more tricky and would probably need 180 minutes certification or (and preferably) at least another engine!!
Common sense is the key to good dispatch practice.
Whooaahh!!!
Join Date: Jun 2002
Location: England
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ETOPS ETP's
Whooaahh could not have put it better. There is a lot of misunderstanding about ETP's, one of which will be the Critical Point on the flight. The whole point is to establish, prior to departure, that enough fuel will be available, at any time in the ETOPS portion of the flight, to divert to an alternate, with the specified fuel reserves.
There is no maximum or minimum number of ETP's, they are purely related to the number of alternates selected in the flight planning process.
Of course, the longer the trip and the fewer the alternates selected (thus ETP's) the greater will be the diversion fuel required. If you don't divert, you arrive at destination with more fuel on board than a KC10. Sensible dispatch is the key to safe and economic operations.
There is no maximum or minimum number of ETP's, they are purely related to the number of alternates selected in the flight planning process.
Of course, the longer the trip and the fewer the alternates selected (thus ETP's) the greater will be the diversion fuel required. If you don't divert, you arrive at destination with more fuel on board than a KC10. Sensible dispatch is the key to safe and economic operations.
Join Date: Jan 2001
Location: UK
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Surely Monty, the ETOP's points to be plotted on a flight plan conicide with time as opposed to fuel reserves???
The ETOPS's certification is measured in time from alternate airfield not fuel required to get to those alternates
The ETOPS's certification is measured in time from alternate airfield not fuel required to get to those alternates
Join Date: Jun 2002
Location: England
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ETOPS
Confirmed, are you sure you are not confusing ETP's with ETOPS? Equal Time Points (ETP) are points where the time to divert to one alternate is the same as to another. At those points you are furthest from an alternate, at all other points you will be nearer. The ETP where the diversion fuel required compared with the fuel on board is most critical, becomes the Critical Point for the ETOPS portion of the trip.
All parts of the ETOPS portion of the trip must lie within the still air distance calculated from the ETOPS approval time (say 180 min) at an agreed speed (approx 400 to 425), depending on your approval.
All parts of the ETOPS portion of the trip must lie within the still air distance calculated from the ETOPS approval time (say 180 min) at an agreed speed (approx 400 to 425), depending on your approval.
