View Full Version : Equal Time Points
76mike
14th Jul 2010, 22:45
If you are on a 120 minute ETOPs flight, upon reaching the Equal Time Point (ETP), must the time to fly to either airport ALWAYS be less than or equal to 120 minutes? Thanks...
shortfuel
14th Jul 2010, 23:55
Nope:
Your Authority has granted your airline with a maximum diversion time of 120 min. This ops specs is only used to determine the ETOPS area of operation (along with the associated max diversion distance).
120 min is not an operational time limitation to conduct a diversion.
FE Hoppy
14th Jul 2010, 23:57
No.:ok:
The actual wind is not used at the planning stage.
... and when push comes to shove, the Commander may decide to fly a different speed than the one used to determine the 120 min distance. As previous posters said, not an operational limitation.
A totally different matter would be to decide to continue to destination instead of proceeding to ETOPS alternate without apparent reason as one airliner did, not too many years ago.
76mike
15th Jul 2010, 01:26
Thanks for the replies, everyone. Yes, there is often confusion between ETOPS--which IS time limited (distance, actually), and the ETPs--which are not. Mike
ImbracableCrunk
15th Jul 2010, 18:16
Wind is considered for ETP. EEP and EXP do not - they are calm wind. (at least that's what they do at my airline.)
Checkboard
15th Jul 2010, 21:53
the Commander may decide to fly a different speed than the one used to determine the 120 min distance.
... but at the planning stage must carry sufficient fuel to fly the speed schedule used for the certification.
ie. you can't use a high speed single engine speed to determine a wide area of operation (with its associated high fuel flow), but on the day plan a fuel-efficient low speed single engine diversion in order to uplift a higher payload.
c100driver
17th Jul 2010, 05:26
Thanks for the replies, everyone. Yes, there is often confusion between ETOPS--which IS time limited (distance, actually), and the ETPs--which are not. Mike
To be precise ETOPs is not time limited at all, but as 76mike said, a fixed distance limit derived from an authorised still air single engine speed for 120 (or 180 etc)minutes.
Also the ETP is always out by approx 2 minutes as no account is taken for the turn (assuming the airfields are ahead and behind):E