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Cat 3
14th Feb 2009, 04:49
During a discussion with my instructor he mentioned that the only strategy we can use in an ETOPS SEGMENT is the fixed speed strategy as this strategy is what is used to determine the Airline's area of operations and hence the maximum diversion distance. I was under the impression that the fixed speed strategy is only for planning purposes and the Commander is free to adopt any strategy from Standard, Obstacle Clearance and Fixed Speed depending upon the circumstances under which the failure occurs.( terrain, smoke, fire etc). My Instructor mentioned that these strategies are only applicable for an engine failure scenario and not for ETOPS. Could someone please enlighten me ?:ugh:

bobrun
15th Feb 2009, 02:44
The speeds schedule or strategies are only for flight planning purposes and to calculate the Rule Distances. In the event of a real diversion during a ETOPS segment, it`s up to the crew to use whatever speed strategy they see appropriate. There's also no need to complete the diversion within the Rule Times either.

Old Smokey
15th Feb 2009, 03:06
What bobrun has said is absolutely correct. The only intention of this post is to reinforce this, in case you thought it a "one off" statement.:ok:

Regards,

Old Smokey

Mansfield
15th Feb 2009, 03:19
And a third voice of concurrence. I believe that I spent a few days in hot water some time ago after our FAA Principal Ops Inspector told me that I had to fly the fixed speed schedule in the event of a diversion, and I rather pointedly told him he was dead wrong. It really depends on how much fuel I want to arrive over the ETOPS alternate with, and how low I want to go in the event of an engine failure. One of the biggest concerns is how much time you spend in ice and how much of a penalty in single engine ceiling that extracts. Faster speed may mean a higher TAT and no ice while at a very low altitude, while a slower speed may mean a below freezing TAT while above the ice nearly al the way there. Of course, if you can't get the TAT high enough, you may be speeding along IN the ice. Lots of variables, which is why the final decision must rest with the operating crew.

Cat 3
15th Feb 2009, 03:30
Thank you guys for the insight, yes I do see that taking into account the variables the strategy depends upon the Crew and further validates the point I was trying to make to my Instructor. Bob run you mentioned that there is no requirement to complete the diversion within the required time limit is that correct ?

c100driver
15th Feb 2009, 05:21
What is important is the intention to fly the airlines ETOPS speed. What you actually fly during the diversion is up to the PinC on the day. You can expect to be questioned by the authority why you deviated from your airline published ETOPS approval.

By briefing anything different your instructor is correct that you are not meeting the ETOPS certification requirements held by your airline. You can however brief different failure case options but the standard ETOPS speed must be the primary option you intend to use, i.e. that is the approval your airline operates under.

I have had this discussion with two different CAA airline inspectors in the passed year from their observation check flights.

bobrun
15th Feb 2009, 06:18
Our ops manual specifically mentions that the ETOPS speed strategy (single engine Mmo/Vmo) is for planning purposes only (to calculate the Rule Distance), and that on the day of a diversion the actual speed strategy used is entirely up to the crew.

Cat3, there's also no requirement to complete an actual diversion within the Rule Time used for planning, correct.

Old Smokey
15th Feb 2009, 11:08
An additional point not covered earlier. You don't have to divert to the airport upon which the ETOPs areas are calculated. If a more distant but more suitable alternate is available, and, in the strategy devised by the crew, safer, then they are free to proceed there.

Regards,

Old Smokey

Checkboard
15th Feb 2009, 13:01
The single engine cruise speed used for ETOPS calculations varies from airline to airline, as each airline can choose the cruise speed they will use for their calculations. Once the cruise speed is chosen, it is used to determine the area of operations (the circles on the ground in which the operator is approved to fly) - and those circles are fixed. That is, they don't change with daily changes in wind or temperature. The trade-off is in choosing a faster single engine cruise (and hence a wider area of operations) the fuel flow increases significantly (and the amount of fuel carried to cover the worse case diversion - which is planned for each flight, taking wind and temp. into account.)

As such, the speed must be one that the aircraft is capable of, and the fuel carried must be enough to support a diversion at that speed. These are purely planning considerations. On the day, the PIC may choose any scenario required to safely return the aircraft to the ground.

What is important is the intention to fly the airlines ETOPS speed. What you actually fly during the diversion is up to the PinC on the day. You can expect to be questioned by the authority why you deviated from your airline published ETOPS approval.

By briefing anything different your instructor is correct that you are not meeting the ETOPS certification requirements held by your airline. You can however brief different failure case options but the standard ETOPS speed must be the primary option you intend to use, i.e. that is the approval your airline operates under.

This is simply incorrect. the only time you can "expect to be questioned" is if you choose a scenario which uses more fuel than you have available at the time - which has nothing to do with ETOPs, as you can expect the same questions any time you run low on fuel.

Cat 3
16th Feb 2009, 07:32
Thanks guys for your invaluable inputs as I do understand the strategy planned upon depends upon the criteria and conditions of flight. The decision rests on what the Commander decides to choose based upon the circumstances. :ok: