ETOPS Flight Planning

[Celestar]

Question about ETOPS dispatching.
Maximun Diversion time (90, 120,..) is only used for determining area of operations, and therefore is not an operational limit for conducting a diversion which has to cope with the prevailing weather conditions (Airbus ETOPS Manual). An ETP is therefore obviously calculated in forcasted atmospheric conditions (logical).
So you determine your area of operations drawing circles using the, let’s say, 90min diversion distance (based on your 1LE speed) centred on each adequate airport.
You then calculated your optimized routing, based on forecasted atmospheric conditions, and make sure this route stays within the circles. You then make sure you have enough fuel for the most critical fuel scenario at CP(ETP). This seems obvious.
Now, what I don’t understand is that I’ve been told that I ALSO have to run my optimized routing OFP in still wind conditions. Your fuel required will of course be different (and could be more restrictive in still wind )… but why do you have to do that?
Any written requirement on this somewhere? I don’t find anything.
In Jetplan user manual:
“To determine if an optimal route meets the requirement of ETOPS, an ETOPS flight plan must be calculated using the optimal route under a “zero wind” condition.”
My opinion is that, if your optimized route stays within the circles (still winds) and you have enough fuel for most critical scenario at CP (forcasted winds), you meet the requirements.
I am probably wrong.

[Lauderdale]

You are not wrong at all Celestar,

The only time you would ever work with still air (as far as I am concerned, is at the planning stage).

I will post a more detailed reply later - unfortunately ETOPS is often the subject of lack of knowledge, especially after the latest FAA update.

For now - rest assured, you are correct! BTW - what do 'they' want you to do with the still air plogs? Hopefully not send them out to the flight crew as well?? Cuz that would just be a recipe for disaster - inmagine mixing up the paperwork when you calculate you fuel requirements!

Cheers buddy - hope the share some ETOPS know how soon!
:ok:

[AxelF]

Hello..

ETOPS;

Rule time 90-120-180
Engine Out Speed just one for Example: 450Kts
With this data you can create Etops Aera Operation Wind=0

Easy...

Last Airport that cover 60Minutes = 450NM you are None ETOPS Area

Then you have a route where the airport range 450NM doesn´t cover the route. You need to extend that area for 90Minutes/675NM or 120Minutes/900NM.

Then you have a suitable aiport for ETOPS within that distance range, remember 675NM or 900NM Wind=0.

ETP Will be the equal time point between the ETOPS Airports.

When you run a Flight plan check the distance from ETP to Airport 1 and ETP Distance to Airport2 that will the same (Equial time/Distance Point), Because the real plan has wind if wind=0 then Time=Distance.

Also that distance will be within the range calculated in the ETOPS Area Operation.

For 90Minutes < 675NM
For 120Minutes < 900NM

I Hope this help your question.

Confirm if you agree and understand?

All the Best.

Axel Fuentes
Consultant Flight Operations

[Lauderdale]

But when you produce the plogs on the day of dispatch the circles on the map are always 0 wind, otherwise you would have very wobbly circles!

So therefore your circles are your gross error check.

It could well be that on the day your time from say ETP2 to ERA is 2.11 on a 120 minute ETOPS approval but you are fully legit as if it were 0 winds you would be <120 minutes - or the other way round; ETP1 to ERA is 01.58 on the day but can be illegal as with 0 winds you are >120 minutes (or whatever your approval is 90,120,138,180 etc). But hey, that is what the circles are there fore - they would have been created during the planning/route analysis stage, so there fore on the day of dispatch you should not have to run a still air plog.

As a seperate issue, you guys have ITT and AMT (both) on your plogs?

[Aviation Jackass]

Axel,
Seems like you are very knowledgeable person seeing you have listed your self as a Flight Operations consultant.

I have a question on 120MINS operations in the North Atlantic?
Is there any specific geographic area where you'll never able to achieve 120MINS ETOPS compliancy?

Thanks
Aviation Jack

[merlinxx]

This does seem to need a little more clarity for some folks, considering the vastly differing interpretations there seem to out there.:ok:

[moodymoosey]

Celestar,

Lauderdale is correct that your circles are your check - in my opinion it is completely unnecessary to have still air plogs and I have never known anyone else do this - unless there is perhaps another reason?

Your flight plan will have a summary that details the diversion time and the critical fuel scenario - this should really be all the thinking you need to do.

The circles are based around a rule DISTANCE and this is fixed according to your approval. All you need to do is, as you said, stay within these circles and have enough fuel to go to either ETP/ERA.

Where you WOULD view the wind or use actual wind is when selecting WHICH airfields to use. For example, if you were routing UK-Antigua (ANU)on 180mins (1200nm) and using just TER vs ANU as your last ETP set, and FDF as your alternate, you would normally be carrying lots of critical fuel.

Therefore, you want to add another ETP set to break up the long 'leg' that is TER vs ANU - so you add BDA and use TERvs BDA and BDA vs ANU. This is normally great and does the trick, except when your route takes you further east towards the Canaries OR if there is a really strong westerly wind making the diversion time to BDA a long one and having the effect of pushing the ETP back up the route to where it was when you were using TER vs ANU.

The answer in this scenario would be to try TFS vs ANU as the winds would not have the same effect on the location of the ETP on this pairing - therefore the forward/backward diversion would be farther down your route and therefore your ETOPS scenario is based on less time at 10000ft and therefore reducing the likelihood of carrying crit fuel

As with any rules, it depends how it is written and how it is interpreted but question your manager to justify the process - ask them why you have to complete the still air plog.

You mention Jetplan so I guess your employer is a Jetplan customer. Jetplan has a significant ETOPS database and there are many options and configurations, other than just your route, that might mean the summary time on your plan exceeds the rule speed yet does not break the circles.

For example, if you bias the distance by 50nm allowing a turn in either direction then your diversion time/fuel will increase yet the actual routing you take remains the same.

I hope this helps

[Lefthandseat]

Hi Mr Axel,
pardon my ignorance but I do not understand some of your points.
U mention check distance between ETP to Suitable Div airports n make sure they are the same but isnt ETP based on TIME? that's why it's called Equitime Point.WHere the ETP will shift is dependent on winds factor & you apply the RWC/CWC formula.In my co.we are more concern if ETP is equal time rather than distance.

Also, in your example, it states 60min=450nm so 120min=900nm. but in both Boeing & AIB ETOPS manual & any performance person will know its not simply a case of rule distx2 as there is the diff of Driftdown slope from EventFL to FL100 (1LE).(depending on which strategy the airline will adopt).
Just wan to confirm.Thank U.
(ps,no offence but I do concur wz the rest here.)

[Falcon_737]

All,

I like to support Axel's explanation. The ETP in this example is 02:12 (normal people will say
more than 120 minutes) but this ETP are under 120Minutes due the distance are within 900NM.

Here some wrong interpretations;
ETP TIME are 2.12= 132 Minutes (Pilots beleve are over 120Min)
But the pilots need to check the distance.


If this distance are inside the 900NM Rule Distance for ETOPS 120Min
That was calculated with WIND=0 for a particular Speed is this case 450Kts

THIS ETP 2.12 is 120Minutes ETOPS operation.


FUEL CRIT TWO ENG
ETP2 AIRPORTS MORA TRK FL DST TIME IAS TAS G/S REQD FUEL FUEL
S0816.70 HKNA 162 298 100 873 2.12 336 395 398 14187 3344 13825
E04942.9 FIMP 039 147 100 862 2.12 336 395 394 14146 3302 13786

[ECBRQ]

HI.

That's OK. I fly for 2.12 hours, but as the distance is less than 900 mn we are legal.

On the other side, if I fly for 1.50 hours but more than 900 nm, am I illegal?

Thanks,

JM

[Falcon_737]

JM,

The time is not important here, just the distance

Bellow 900NM you are in ETOPS 120, You can have times from 1.45 to 2.10 but if you are in the range you are in legal ETOPS 120.

Best Regards.

[to_dan]

Hi all,

What's wrong if I use only one ETOPS alternate instead of two. That may be the case if I consider weather minima which is more restrictive for ETOPS. In that case I would have to use 60mn circle alternate with an ETOPS 90 or 120 etc... alternate

Thanks

[vipero]

to dan... good filosophy. no need to calculate any ETP then...

[to_dan]

to Vipero,

Instead of ETP you have to take into account as ETOPS entry and exit the limit of your ETOPS circle along with the calculation of your diversion time