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Enroute alternate required at the planning stage

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Enroute alternate required at the planning stage

Old 20th Jan 2016, 15:13
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Enroute alternate required at the planning stage

Gentlemen,

Question, something that has been bothering me for awhile. I've tried google and came across some discussion on the topic on this forum but the answers seemed inconclusive.

It's about alternates. Under specific conditions we need a take off alternate. We almost always need a destination alternate( EU OPS have conditions where you don't need a destination alternate, but that's beside the scope of my question), sometimes two. If we want to reduce the contingency fuel from 5% to 3% we need an enroute alternate.

There is a table that specifies the weather that the destination alternate and 3% alternate have to comply with and that is ultimately where my question is later on.

We also need 60 minute alternates if we fly a twin(B73) but they only need to be adequate and,

If we cannot enroute, for a twin maintain at least a positive climb gradient at least 1000 ft above terrain we need to clear al terrain and divert to an alternate where a landing can be made taking into account performance and meteorological conditions.

So, to summarize, there are 5 different type of alternates. Each specifies their WX requirements.

- TO alt: you need to be able to land taking into account N-1 conditions;
- 3% ERA: you need WX according to table in EU OPS 1.297
- DEST alt: you need WX according to table in EU OPS 1.297
- 60 minute alternates which only have to be adequate according to EU OPS
- Alternates in case of engine failure over high terrain where you cannot maintain a
Positive climb gradient at at least 1000 ft above terrain, you need to be able to clear
all terrain and be able to divert to an airport where a safe landing can be made taking
Into account field conditions and WX conditions

This is all very clear to me!

However, EU OPS 1.192 mentions an enroute alternate required at the planning stage!!

Furthermore EU OPS 1.297 mentions the table that specifies the WX requirements for the following alternates; destination alternate; isolated destination alternate; 3% fuel alternate AND enroute alternate required at the planning stage.

WHAT IS MEANT BY THIS enroute alternate required at the planning stage????

- It is not the TO alternate!
- It is not the destination alternate since it is already covered in the table!
- It is not the 3% alternate since it is already covered in the table!
- It is not the TO alt since it only needs to comply with WX taking into account N-1 limitations.
- it is not the alt required according OPS 1.500 since that only requires weather reports or forecasts, or any combination thereof, and field condition reports indicate that a safe land-ing can be accomplished at the estimated time of landing.

So my questions is: what does EU OPS mean with the phrase enroute alternate required at the planning stage??

Below are copy/paste segments from the applicable regulations.

Many thanks in advance








OPS 1.192

Terminology

(a) Adequate Aerodrome. An aerodrome which the operator considers to be satisfactory, taking account of the applicable performance requirements and runway characteristics; at the expected time of use, the aerodrome will be available and equipped with necessary ancillary services such as ATS, sufficient lighting, communications, weather reporting, navaids and emergency services.

d) En-route alternate (ERA) aerodrome. An adequate aerodrome along the route, which may be required at the planning stage.

(e) 3 % ERA. An en-route alternate aerodrome selected for the purposes of reducing contingency fuel to 3 %.

Routes and areas of operation

(a) An operator shall ensure that operations are only conducted along such routes or within such areas, for which:

5. If two-engined aeroplanes are used, adequate aerodromes are available within the time/distance limitations of OPS 1.245;

OPS 1.297

Planning minima for IFR flights

(c) Planning minima for a:

destination alternate aerodrome, or

isolated aerodrome, or

3 % ERA aerodrome, or

en-route alternate aerodrome required at the planning stage

An operator shall only select an aerodrome for one of those purposes when the appropriate weather reports or fore-casts, or any combination thereof, indicate that, during a period commencing one hour before and ending one hour after the estimated time of arrival at the aerodrome, the weather conditions will be at or above the planning minima in Table 1 below.

Tabel not included!!



OPS 1.500

En-route One engine inoperative

(a) An operator shall ensure that the one engine inoperative en-route net flight path data shown in the Aeroplane Flight Manual, appropriate to the meteorological conditions expected for the flight, complies with either subparagraph (b) or (c) at all points along the route. The net flight path must have a positive gradient at 1 500 ft above the aerodrome where the landing is assumed to be made after engine failure. In meteorological conditions requiring the operation of ice protection systems, the effect of their use on the net flight path must be taken into account

(b) The gradient of the net flight path must be positive at at least 1 000 ft above all terrain and obstructions along the route within 9,3 km (5 nm) on either side of the intended track.

c) The net flight path must permit the aeroplane to continue flight from the cruising altitude to an aerodrome where a landing can be made in accordance with OPS 1.515 or 1.520 as appropriate, the net flight path clearing vertically, by at least 2 000 ft, all terrain and obstructions along the route within 9,3 km (5 nm) on either side of the intended track in accordance with subparagraphs 1 to 4 below:

4. the aerodrome where the aeroplane is assumed to land after engine failure must meet the following criteria:

(i) the performance requirements at the expected landing mass are met; and

(ii) weather reports or forecasts, or any combination thereof, and field condition reports indicate that a safe land-ing can be accomplished at the estimated time of landing.
flyburg is offline  
Old 20th Jan 2016, 15:58
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1. EU-OPS is not valid anymore, except for Subpart Q, which is due to be replaced next month. Look at EASA AIROPS.

2. I think the "or enroute alternate required at planning stage" covers the rapid decompression or engine failure over high terrain scenarios.
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Old 20th Jan 2016, 21:19
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WHAT IS MEANT BY THIS enroute alternate required at the planning stage????
The only times I used 3% contingency was only because we were performance limited. Slightly above MTOW, reducing from 5% to 3% (couple of hundred kgs) for long flights (B738). I guess it was indeed a planning stage requirement, otherwise we wouldn't be able to dispatch.

I'm not sure if thats the answer we were looking for but I hope it helped.

Qwerti
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Old 25th Jan 2016, 17:16
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Alternate require at planning stage

I was a bit disappointed to see this one dropping down the page because I find the wording rather ambiguous as well.
Don't blame originator for quoting from EU OPS because it's a lot easier to navigate around than the new EASA stuff.
From what I have seen the wording in EASA is pretty much identical, but still is open ended as to what other ERA may be required at the planning stage. Only a guess but it may be that it is simply a catch-all phrase to cover any eventualities.
My experience of SAFA checks is that they look for Alternates and ERAs on the flight plan and then check to make sue you have the appropriate weather for those airports.
Any ideas anyone?
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Old 25th Jan 2016, 17:37
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No enroute alternates are required if using contingency 5% and not ETOPS operations.
Basically, if not ETOPS, then by definition, there are adequate airports within 60 min. Enroute anyhow.
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Old 25th Jan 2016, 18:20
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As discussed, operators tend to reduce the 5% to 3% when they have restrictions on the amount of fuel they can take either due to MTOW or MLW limitations.

Briefly from AMC:

3. Contingency fuel, except as provided for in (b), which should be the higher of:
i. Either:
ii.
(A) 5% of the planned trip fuel or, in the event of in-flight replanning, 5% of the trip fuel for the remainder of the flight;
(B) not less than 3% of the planned trip fuel or, in the event of in-flight replanning, 3% of the trip fuel for the remainder of the flight, provided that an en- route alternate (ERA) aerodrome is available;
or an amount to fly for 5 minutes at holding speed at 1 500 ft (450 m), above the destination aerodrome in standard conditions.

Location of the Fuel En-Route Alternate (Fuel ERA) Aerodrome (AMC2 CAT.OP.MPA.150(b))
The fuel ERA aerodrome should be located within a circle having a radius equal to 20% of the total flight plan distance, the center of which lies on the planned route at a distance from the destination aerodrome of 25% of the total flight plan distance, or at least 20% of the total flight plan distance plus 50 NM, whichever is greater. All distances should be calculated in still air conditions.
The applicable weather minima are the same as for destination alternate aerodromes:
Avenger is offline  
Old 25th Jan 2016, 21:16
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Enroute alternate is only an issue in non-ETOPS flights for fuel reduction requirements, as a previous poster responded. It enables the operator to plan a flight with a reduced fuel requirement, using 3% contingency fuel rather then 5%, by taking into account the capability to land before destination in case of an adverse fuel use scenario.

Example flight from Canaries to UK, B738 trip 13,000kg thus contingency fuel requirement of 5% would be 650kg, 3 % would be only 390kg.
If this island would be takeoff performance limited, such as ACE, this would enable the crew to take on some additional bags or passengers. Thus by designating e.g. OPO as an ERA it would enhance payload if required.

Think of a BBJ/B737 ETOPS flight flying AMS-IAH, trip ~29,000kg thus contingency fuel of 5% would be 1,450kg vs 3% 870kg this becomes even more pronounced. Such flights may even benefit from decision point procedures enabling further fuel reductions thus extending range/payload...
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Old 25th Jan 2016, 22:10
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Despegue, Avenger, Skyjob

I agree with you all. I think the original question was regarding why the regulations state you need to apply planning minima for the 3% ERA , or 'any en-route alternate required at the planning stage'

Why not just leave it at 3% ERA since there are no other en-route alternates required ( at least as far as we have established in this discussion)
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Old 26th Jan 2016, 08:29
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Thanks for the replies and apologies for the absence. Indeed, EU ops doesn't apply anymore. I have digged out the EASA ops. I work with part A, however, wording in it was (purposely) hard to interpret so I did some digging in the rules. Didn't make it any more clear, hence my question on here.

I'm well aware of the 3% ERA! That wasn't my question. My question was: in the planning table it mentions BESIDES the 3% ERA also that the planning minima have to be applied to " alternate required in the planning stage"! What is meant by this? I, unfortunately, disagree with some of the conclusions. After reading some more into the rules and reading over our part A, I do believe they mean the 60 minute ERA by this! Not only have do they have to be adequate, but also in the planning stage, they have to be above the mins in the table.

Any more insights would be appreciated!

Last edited by flyburg; 26th Jan 2016 at 13:13.
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Old 26th Jan 2016, 12:08
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Flyburg,

If indeed you need an ERA for planning purposes, these ERA must be indeed suitable. Meaning that the same minima apply as to Dest. Alternates. Otherwise, it wouldn't make sense to have these alternates anyhow doesn't it?!

Once you are inflight, planning minima do no longer apply, but you sure must be able to land enroute, just like ETOPS.
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Old 26th Jan 2016, 13:16
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Ok, Thanks!

Last edited by flyburg; 26th Jan 2016 at 13:45.
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