ETOPS Requirements Routes Atlantic

[dl777jet]

Hello,
some European airlines using Santa Maria, Portugal (LPAZ) as a fuel stop for caribic flights. I'm learning for flight dispatch license and I wonder if this routing would allow an ETOPS 120 on a 757-200 aircraft, provided both the operator and aircraft meet requirements:

LPAZ-MUVR

DCT 37N040W 35N050W 32N060W DCT WINGZ DCT
SHEIL M330 RUDLI M593 GRATX/N0464F360 B646 ZQA R628 TANIA/N0413F240 R628 UVA


Which alternate airports would be the right to choose ?


thanks for your help

[BOAC]

Just get a map and draw the circles! Try 800nm.

[Henry VIII]

Remember by heart the canadian CYYT, CYJT, CYYR, CYHZ, CYQX and afterthat Bermuda TXKF (take care to the night closing), US shoreline apt as like as KBGR, KBOS, KEWR, KJFK, KORF, KILM, KCHS down to KMIA or other carribeans like TAPA, TJSJ, MDSD.

As said, try to draw the circles :ok:

[dl777jet]

Do I also take actual wind forecast into consideration ? Do I use the right formula ? 389 kt TAS + 10 % for GS in FL100 + or - winds in 100 ? Or is a dumb formula 120 minutes at 389 kt GS ? If the winds etc. plays a role could it be that a flight must be canceled because no alternate available in given 120 minutes ? Does all the EU carriers have the possibility to add 15 % margin for ETOPS 120 so that it makes ETOPS 138 ? thanks for all your help friends

[Henry VIII]

Wind, as like as all wx, to be considered from 1 hr before earliest ETA to 1 ur after latest ETA. Do not know the reported GS rule of thumb.

If wx do not allow to consider suitable an adequate airport you have to find another way to reach destn.
From Europe to Americas you can consider nothern routing via Iceland taking into account Greenland apt or the Blue Spruce routes. With refuelling stop in Canada Newfounland.

[Green Cactus]

You do not have to take the wind into account, if you have 120 minutes approval, just take your driftdown speed and draw the circles.

Of course all airports need to be open (weather/notams/opening hours) when you actually might need them.

I do recall there was a certain allowance for the initial deceleration, not sure how much that was.

[BOAC]

The route has to stay within 120 mins IN STILL AIR AND ISA at the given single-engine ETOPS speed approved by the regulator. Just simple circles on the chart! If you are studying for an exam question you will be given this figure.

138 mins after 3 months of 120 mins operations as far as I know.

Try Google for 'ETOPS' or search PPrune for more. AB have a good publication.

[slamer.]

Great Circle Mapper (http://gc.kls2.com)

[Checkboard]

Do I also take actual wind forecast into consideration ?
No - ETOPs are stated as "120 minutes" as an indication of the time flown on one engine, but the actual approval is for a circle of a specific distance.

Do I use the right formula ? 389 kt TAS + 10 % for GS in FL100 + or - winds in 100 ?
The operator selects a single engine cruise speed which will result in a large enough circle of operation around each adequate airfield. The higher the selected single-engine cruise speed, the larger the circle approved - but the penalty is the higher fuel load required to be carried to permit a single-engine diversion at the nominated speed from the most critical diversion point.

Or is a dumb formula 120 minutes at 389 kt GS ?
See above - the distance is different for each operator.

If the winds etc. plays a role could it be that a flight must be canceled because no alternate available in given 120 minutes ?
Wind doesn't play a role - for the reason you have stated - a scheduled airline would be constantly cancelling flights, based on the winds aloft, not to mention the pain calculating the correct area of allowed operation for each flight. As the "120 minutes" is a somewhat abitrary figure, based upon the statistical chance of a furthur failure in that time, the few minutes either way added by the wind is negligible in the risk calculation.

As stated above, though, the wind does need to be allowed for in the flight planning of the single engine diversion contingency fuel to ensure that the aircraft always has sufficient fuel to reach an alternate given an engine failure at any point along the route.

Does all the EU carriers have the possibility to add 15 % margin for ETOPS 120 so that it makes ETOPS 138 ?
ETOPs are approved on an operator basis. They cost money, so are not applied for unless you need the performance. 60 minutes is "standard". 120 minutes covers twin engine operations across the Atlantic. 138 minutes covers northern routes, when an airfield is closed due weather. 180 minutes give you Pacific operations etc. You apply for what you need.

[Tim Zukas]

No idea what alternates are allowed, or what ETOPS distance you can use-- but if you can use 800 nm from St Johns and Bermuda, then...

World Aeronautical Database (http://www.worldaerodata.com) says CYTT is at 47.618610N, 52.751945W and LPLA is at 38.761842N, 27.09079W. It turns out that 36.16543966N, 43.54313521W is the place that's 800 nm from both of those positions. It turns out that 34.58778995N 48.94366471W is 800 nm from St Johns and Bermuda, assuming the latter is at 32.364042N 64.678703W. So you need to stay north of those two points, and at a glance it looks like your route does so. You can confirm that by using the NGS calculator

INVERSE computation (http://www.ngs.noaa.gov/cgi-bin/Inv_Fwd/inverse2.prl)

to find your initial course from 37N 40W to 35N 50W is 259.15 degrees, while the initial course from 37N 40W to the first corner of the no-fly zone is 254.78 degrees and to the second corner is 254.34 degrees. So you are indeed passing north of both of them.

Once past the second corner you're always well within 800 nm of someplace.