Jump to content
Sign in to follow this  
Chuck Dreier

ETOPS/Fuel Question

Recommended Posts

As Kyle said you are require to have enough fuel even for 1EO + Decomp, the 3 scenarios that are required for ETOPS briefly are:

 

1- All ENG with Decomp. (10.000ft)

2-1EO with Dcomp. (10.000ft)

3- 1EO without Decomp (Driftdown altitude), Drifdown as you cannot maintain the same altitude with just One Engine.

 

All these calculations + APU running and 10% for icing, these calculations are based on the worse case scenario that 99.99% never gonna happen, if you end up needing more fuel to meet those requirements its gonna be added into ETOPS reserve.

 

Thanks for clarifying that sir. I dream of making my own ngx ETOPS flight to Hawaii by the book and completely legal release. Still a ways away obviously.

Share this post


Link to post
Share on other sites

I was a pax on a Continental B737-700 KSNA-PHOG, and I've simulated numerous B787/738 flights from multiple locations to/from the islands using PFPX and never had a problem with the planning.

 

The flight I took was memoriable because there were more people in 1st Class than coach, we had our choice of almost any seat or row for that matter and the sunset enroute was startlngly beautiful. I say almost any seat because the attendent would not allow you to sit in a "extra cost seat" unless you paid the additional fee LOL. She was nice enough to show us how to use the seat cushion as a pillow.

 

Don't forget to use the fuel crossflow in the last hour of flight, there's also some electrical checks but I'm not up on those.


Dan Downs KCRP

Share this post


Link to post
Share on other sites

Actually we did for a while as an intermediate step of certification, until we had enough data to prove our APUs would start reliably when cold-soaked. Wasn't sure if that was what ya meant.

 

This is something that gives more reliability to the APU which is always a good thing, and it does not affect what was said in my previous post, ETOPS fuel requirements remains the same until there will be a change in that regulation.


Arslan Nouar

Share this post


Link to post
Share on other sites

Out of curiosity - assuming you're using the latest version of PFPX (1.23), what flight levels are you getting throughout the flight?

 

Do you have anything selected in the "Optimisations" section? It defaults to "Fuel" -- but in my experience it is buggy and usually results in holding you down at extremely uneconomical levels for long periods of time. Try selection "None" from the dropdown (should grey out the little green light) and re-run the calculations: you might be pleasantly surprised.

Share this post


Link to post
Share on other sites

I want to fly an ETOPS operation KSEA-PHNL.  Maximum fuel on the PMDG 737-800 is 45,900 pounds.  The required fuel for this trip is 49,165 lbs.  Alaska Airlines flies this route ETOPS daily.  My question is whether there's a way to make an adjustment in the PMDG 737-800 to extend the fuel load?  If not, that eliminates quite a bit of my long route plans.  Thanks guys!

When you have a chance could you provide me with your payload or ZFW.

Share this post


Link to post
Share on other sites

This is my PFPX output using the upcoming 0330z departure 9/23/2015 of Alaska 893 and today's real world routing:

HAROB5 HQM SEDAR 4200N 13300W 3900N 13700W HELOP A332 AUNTI R463 APACK MAGGI3

FUEL ENDUR
TRIP 34650 ........ 05:45
10 PCT 3120 ........ 00:34
ALTN PHOG 2320 ........ 00:21
INTL HOLD 2393 ........ 00:30
ETP ADD 1448 ........
MIN T/O 43931 ........ 07:10
EXTRA 0 ........ 00:00
TAXI 520 ........ 00:20
RELEASE 44451 ........ 07:30

ZFW TOW LDW
MAX 136000 174200 144000
PLN 130269 174200 139545

That is 35,490lbs of payload using a DOW (dry operating weight) of 94,779lbs. and the maximum MTOW Boeing offers on the -800 of 174,200lbs.

Not bad for a 2,563nm (air distance) trip. Almost 200nm greater than the flight-plan distance due to the 33kts of average headwind (forecast).

ETOPS alternates used are (KOAK and PHNL) and using ETOPS 180 with 1185nm maximum diversion distance.

Remember, in the real world Alaska Airlines will carry more payload / lbs of fuel than we will be able to with the PMDG -800! Why?

They are currently going through with the split scimitar retrofit on most of the -800s and all of the -900ERs. Over this trip length a SSW fitted -800 will burn ~2% less block fuel (impressive!) than a blended winglet fitted -800 (as modeled by PMDG). That would result in a ~880lbs block fuel reduction on this flight (more weight for payload).

The U.S. Flag (Jet) fuel policy doesnt make matters better considering the 10% F.A.R. reserve requirement... Many international operators, under EU-OPS and others such as Emirates, Cathay, British Airways, KLM etc. have been using statistical contingency fuel for many years now (very successfully).

In essence they track individual contingency burn over hundreds/thousands of flights on each specific route and then they load contingency fuel to cover 90/95/99% of those flights.

This of course means the statistical contingency figures change on individual routes as the time of year changes and thus the weather etc. Beats having to carry around 5% or 10% like the U.S. carriers have to. At least the F.A.R/s allow in-flight re-dispatch, which allows the 10% requirement to be reduced significantly as it is calculated from re-dispatch point to final destination. That of course is not a option on this specific route, due to the obvious lack of en-route/re-dispatch alternates.

I have heard the FAA will finally move towards a new policy called performance based fuel (different name for statistical contingency). Something the major U.S. operators have long been pushing for, especially the ones such as United, AA, Delta who have to carry thousands of pounds of extra contingency fuel under current regulations. This will of course come with many valid requirements such as tracking individual aircraft burn, route performance etc. (which I'm pretty sure all three already do to monitor aircraft/engines etc.).

In any case, ~35k + payload is a full 160 seater -800 with crew, bags, pantry etc.



Also do not forget about the ETOPS 180 distance you have set in the aircraft profile within PFPX.

Different operators will choose difference maximum diversion distances for 60/120/180 minutes on the 737NG.

For example, one U.S. 737NG operator uses 1185nm as the ETOPS180 distance on their -700/800. Another U.S. 737NG operator uses 1080nm.

Why the difference?

The operator using the latter, and lower figure for planning purposes, does not require more and hence avoids having to carry the extra 105nm of ETOPS critical fuel (when critical fuel is needed) to cover for worst case scenarios (1 engine out, 1 engine out + depress. and depress only). The operator using 1185nm needs the extra 105nm for certain routes. There is of course a maximum still air 1EO distance for each ETOPS aircraft. It is up to the operator and its needs to determine if it needs and wants to plan up to the full capability.

  • Upvote 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

  • Tom Allensworth,
    Founder of AVSIM Online


  • Flight Simulation's Premier Resource!

    AVSIM is a free service to the flight simulation community. AVSIM is staffed completely by volunteers and all funds donated to AVSIM go directly back to supporting the community. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. Thank you for your support!

    Click here for more information and to see all donations year to date.
×
×
  • Create New...