ETOPS calculations.
Thread Starter
Joined: Apr 2005
Posts: 7
Likes: 0
From: Europe
ETOPS calculations.
Hello there,
I have a question regarding the critical fuel scenarios with the etops calculations.
When the single engine speed has been determined for example TAS of 340 kts. Do the critical fuel scenarios have to be calculated with this speed or is this speed only of use to determine the range? For example 120 min so the range rings will be 680nm.
Any help on the subject is very much appreciated.
Or any directions on where to find it.
Thanks
I have a question regarding the critical fuel scenarios with the etops calculations.
When the single engine speed has been determined for example TAS of 340 kts. Do the critical fuel scenarios have to be calculated with this speed or is this speed only of use to determine the range? For example 120 min so the range rings will be 680nm.
Any help on the subject is very much appreciated.
Or any directions on where to find it.
Thanks
Joined: Oct 2004
Posts: 381
Likes: 1
From: KORR somewhere
Not sure, but this is something I use at work for rough planning...
Great Circle Mapper
The blue hyperlinks off the ETOPs rule/time section should give you some guidance.
Hope its of some help.
Great Circle Mapper
The blue hyperlinks off the ETOPs rule/time section should give you some guidance.
Hope its of some help.
Joined: Jul 2008
Posts: 1,335
Likes: 0
From: south pacific vagrant
If you plan your range circles at a certain TAS, you must also carry the fuel to achieve that TAS, with minimum reserves at landing.
Whether or not the crew elect to fly at that speed is another matter.
If this amount of fuel is not carried then they must fly slower and then by definition could be outside the 120min (or whatever) approval. Remember, an ETOPS requirement is to be within a certain time of an adequate airport, not a certain distance.
Whether or not the crew elect to fly at that speed is another matter.
If this amount of fuel is not carried then they must fly slower and then by definition could be outside the 120min (or whatever) approval. Remember, an ETOPS requirement is to be within a certain time of an adequate airport, not a certain distance.
Joined: Jan 2001
Posts: 242
Likes: 0
From: Rome, Italy
There are two conditions:
1) ETOPS Route validation. It means the route must be within the circles with centers on adequate airports and calculated according to the single engine approved speed per time (still air).
2) Fuel critical scenario. It must include the engine out fuel calculation plus decompression, emergency descent fl100 etc... and consider the higher fuel.
Normally the planning system would use a IAS (costant value), to be then converted in TAS at 10.000ft (then you would see a critical fuel scenario showing different TAS).
1) ETOPS Route validation. It means the route must be within the circles with centers on adequate airports and calculated according to the single engine approved speed per time (still air).
2) Fuel critical scenario. It must include the engine out fuel calculation plus decompression, emergency descent fl100 etc... and consider the higher fuel.
Normally the planning system would use a IAS (costant value), to be then converted in TAS at 10.000ft (then you would see a critical fuel scenario showing different TAS).
Per Ardua ad Astraeus
Joined: Mar 2000
Posts: 18,575
Likes: 4
From: UK
Just to ezxpand on vipero's post - the critical fuel calculation DOES have to allow for wind effect - as in normal route/div fuel planning, whereas as stated, the route planning does not (as long, of course, as the actual limiting critical fuel requirement can be achieved on the planned route)..
