ETOPS and the ETP

[vincenzo vaughnetto]

Fact or fiction?
Within the last month, an Australian registered Airbus 330, en route from Australia to Honolulu, had an engine roll back to idle prior to the CP for Honolulu and the Marshall Islands ETOPS segment, and continued on to destination.
The flight was completed safely. That is the most important point.
However, what caused the problem and what do we consider to be a critical system failure, if not an engine rolling back to idle?
There are many considerations. If the event occurred, can we have a fair and balanced discussion of all options?

[AutoPilotA]

Hmmm

That would be either Jet* or QF ? Not sure if QF ever use the 330 on that route ?

[unseen]

What do you think they should have done and why?

Are you suggesting they should have diverted to the Marshall Islands because they were prior to the CP?

[AutoPilotA]

Would be a brave man (or woman) to take take 300 odd pax to a little island in the middle of the ocean !..... in the dark !.... I reckon..... unless there was no other option that could be justified !

[Wizofoz]

I'm not familiar with the route, but know a little about ETOPS.

Just because an airfield has been nominated as the ETOPS suitable in order to comply with ETOPS, this does not mean the aircraft must divert to that particular aerodrome in the event of a failure.

"Land at nearest suitable airport" (or AB equivalent) still applies- as does the decision making in determining what is and isn't the most suitable at that moment.

If it was clearly safer and not much further to continue, that is absolutely justifiable.

[waren9]

etp and cp have different definitions.

suggest you reword your post to get the discussion you are fishing for

[haughtney1]

Without knowing what is specifically contained within the relevant QRH et al, it is hard to do anything other than speculate.
A rollback as you suggest, would not, I assume, mandate diverting to the nearest piece of tarmac. You still have all the relevant services associated with the engine, so at least initially from a generic standpoint you have a little more time up your sleeve to think.
Its far more cut and dry when for example you have to secure the engine due to indications of further damage, no oil pressure/quantity etc etc.
But lets assume its just a rollback, what are the other engine indications showing? have you had any external confirmation/information regarding further damage to the engine airframe? Is the other engine performing as expected? Did you dispatch with an APU? (you can fly ETOP's without one)
Whats the weather like at your likely diversion airfields? navaid status etc etc etc, the list goes on and on.
Only then, with a decent amount of situational awareness can you realistically come up with a reasonable set of options, one of which might be continue to destination:E

[compressor stall]

Out of interest - where does the company (which ever one it is) define the EEP on that route....

(I'm not trying to second guess the crews actions, but the unique Australianism of the rules' interpretation is worth discussing).

[blueloo]

Would not the critical point re engine failure or rollback (other than severe damage considerations) be primarily concerned with drift down to E/O cruise altitude and being able to make the nearest suitable or adequate with the appropriate reserves.

If sufficient fuel is on board to make destination (plus required reserves) and assuming they have not gone past the nearest suitable then there probably shouldn't be an issue. (I think the actual requirement is that it can't be beyond the maximum diversion time or distance....)

Additional fuel ordered over flight plan fuel will in some cases change your ETOPS /DPA/CPE data. (Also depends on airport availability on certain routes)... It's just that many do not recalculate it.

Airmanship may ultimately dictate a different course of action.

[gordonfvckingramsay]

From CAO 20.6, "Continuation with 1 or more engines inop":

3.2 The pilot in command of a multi-engine aircraft in which 1 engine fails or its rotation

is stopped, may proceed to an aerodrome of his or her selection instead of the nearest

suitable aerodrome if, upon consideration of all relevant factors, he or she deems such

action to be safe and operationally acceptable. Relevant factors must include the

following:

(a) nature of the malfunctioning and the possible mechanical difficulties which may
be encountered if the flight is continued;

(aa) the nature and extent of any city, town or populous area over which the aircraft is
likely to fly;

(b) availability of the inoperative engine to be used;

(c) altitude, aircraft weight, and usable fuel at the time of engine stoppage;

(d) distance to be flown coupled with the performance availability should another
engine fail;

(e) relative characteristics of aerodromes available for landing;

(f) weather conditions en route and at possible landing points;

(g) air traffic congestion;

(h) type of terrain, including whether the flight is likely to be over water;

(i) familiarity of the pilot with the aerodrome to be used.


Most airlines employ some sort of decision making model. I assume the crew took all of these items into account and made the call based on that.

[1a sound asleep]

MAJ has no ATIS only a unicom. No idea how long it takes to wake somebody up there. I think I would continue to HNL assuming everything else seems ok

PPR FOR NGT LNDG BY ARPT MGR/DIST ADMIR, EXCP EMERG, RPRT WI 48 HOURS.

200' TWR LCTD 07-06-15N & 171-22-22E OBSTN LGTD.

PARTIALLY PAVED WATER CATCHMENT AREA BOTH SIDES OF RWY WITH VENT PIPES 1' ABOVE SFC.

[swh]

3.2 The pilot in command of a multi-engine aircraft in which 1 engine fails or its rotation is stopped

Excuse me if I am pointing out the obvious, I would think an engine operating at idle has not failed or stopped rotating. Otherwise I have multiple engine failures every flight.

[compressor stall]

MAJ has no ATIS only a unicom. No idea how long it takes to wake somebody up there.

IF - and I repeat IF - MAJ was one of their nominated EDTO alternates, then according to the regs they would be ready in 30 mins.

(That, however, still doesn't mean you must head there).

[FYSTI]

SWH beat me to it.
which 1 engine fails or its rotation is stoppedThis is the key clause, in the case of roll-back, did either of those conditions occur? A malfunction yes, a failure or its rotation stopped, hmm? Airbus go to great lengths in their FCOM bulletin to give guidance for the avoidance of unnecessary in-flight shutdowns. More info directly from Airbus (http://www.airbus.com/fileadmin/media_gallery/files/safety_library_items/AirbusSafetyLib_-FLT_OPS-SUPP_TECH-SEQ07.pdf).

Splitting hairs, yes, but there are subtle differences between the regulations & the manufactures guidance creating a large grey area in the case of reduced thrust operation - which is Airbus policy unless a checklist directs the engine to be shutdown.

[gordonfvckingramsay]

Was thrust restored or available? If not, it is little more than an APU.

Either way, CAO 20.6 allows the crew to make a decision to continue to a suitable alternate based on all those criteria and not just the closest one. That was my point :ok:

[The Green Goblin]

Sounds like another faulty thronomeister.

Unless you were on the FD, then the decision making is not your business.

[Capt Fathom]

Unless you were on the FD, then the decision making is not your business.

It is of interest if you happen to be a passenger on that flight!

[aveng]

How long ago was this? Because QF fleet have been modified to prevent this. The dedicated generator is used to supply power to the engine computer when running above 15%, since the mod - aircraft power can supply the EEC if dedicated gen supply fails.

[clark y]

Failed/rolled back what's the difference? Splitting hairs. As Gordon said it's little more than an APU. Your basically in a 200 ton single engine aircraft in the middle of the Pacific. As for the incident in question I was not on the flight deck so will not comment on the decision making process.
Manufacturers and airlines do not like inflight shutdowns because it may affect ETOPs/ETOPs approvals and makes the media. I'd like to know what caused the roll back and how to rectify it. Shame you can't have direct law on the engines like flight controls.

[The Green Goblin]

Quote:
Unless you were on the FD, then the decision making is not your business.
It is of interest if you happen to be a passenger on that flight!

That's why the crew are paid the big bucks :hmm:

To keep the Trents and Shazzas of this world oblivious. After all, modern aircraft fly and fix themselves. We are glorified bus drivers who just sit there, push buttons and drink coffee.

:ok:

[ekolbregit]

I operate ETOPS/EDTO a couple of times per month, so I have a genuine interest in this topic.

Once upon a time, twin engine high capacity turbine aircraft had to be operated within 60 minutes of an adequate airport.

In case one engine failed, the reliability of the remaining engine was seen to be no more than 60 minutes, based on statistics and the probability of a further in- flight shutdown. (My interpretation and understanding.)

That was as far as the authorities allowed us to go.

Even today, if we depart an airport that is closed for arrivals, we still need to provide a take-off alternate within 60 minutes flight time of departure at single engine cruise speed in case we have an engine failure during the departure. Why is this?
Safety of aircraft, safety of the passengers, further technical difficulties etc.

Then, we wanted to go further, so straighter tracks were planned taking us greater than 60 minutes from an adequate airport, and ETOPS/EDTO evolved.
Still based on statistics for an in flight- shutdown, 90, 120, 150, 180, 240 minutes from an adequate airport was granted, based on the regulators approval for such operations.

Often during ETOPS/EDTO, there are other available adequate airports closer than the ETOPS pair that can be considered. That is why my ETP pair is always the 2 closest available airports, in case something unforeseen should happen. ETOPS/EDTO just defines the area of operation. It doesn't dictate where you must go within the area of operation.

So, PKMJ to PHNL. It's great circle distance is 1981 NM. No other airports available. An offset ETP will be at slightly greater or much greater than half great circle distance (990 NM). It really doesn't matter as long as we don't fly more than 3 hours in either direction. Otherwise, we are flying contrary to our aviation authorities ETOPS/EDTO regulations. Refer CAO 82.0 appendices 4 and 5, EDTO.

United Airlines fly to Majuro 3 days a week in a B737-800, so the airport is more than capable of handling an A330. RNAV approach both runways. As good as an ILS. Would we have any qualms about performing the 34 RNAV approach at YMML? Probably not I'm guessing. Given 2 hours notice, how unlikely would it be that the airport, stipulated for such eventualities, would not be available for us to use? Forget PAX comfort for the minute. We are up to 3 hours over water from the closest available airport, now on 1 engine. Passenger and aircraft safety are the only things that matter.

At what point do we say continue to Honolulu. 3 hours before Honolulu? definitely. At 3.5 hours before Honolulu? most likely. Any longer than 3.5 hours when an adequate airport, let's assume with ok WX is available, at less flying time? Where do we draw the line?

It would depend on the nature of the problem, where the problem occurred, whether you continued toward destination while trying to sort it out, (should you turn towards the closest airport while trying to sort it out?), the possibility of further problems and where all this left you reference to either airport once the final decision was made.

Either way, the flight time remaining needs to be less than 3 hours on single engine.

It is all about passenger and aircraft safety within the regulations. Operator convenience and PAX comfort have nothing to do with it.

[waren9]

Even today, if we depart an airport that is closed for arrivals, we still need to provide a take-off alternate within 60 minutes flight time of departure at single engine cruise speed in case we have an engine failure during the departure

not the case for jq unless departing from nz or japan

It really doesn't matter as long as we don't fly more than 3 hours in either direction. Otherwise, we are flying contrary to our aviation authorities ETOPS/EDTO regulations

again, not the case at jq

Either way, the flight time remaining needs to be less than 3 hours on single engine.


as above

what mob do you fly for ekolbregit? sounds like a few differences there

[compressor stall]

Either way, the flight time remaining needs to be less than 3 hours on single engine.

Not true, even for 180 minute EDTO.

[PPRuNe Towers]

This situation and thinking about it was first mooted on PPRuNe more than 10 years ago.

A very similar incident with a heavy, trans Pacific twin and an engine going sub idle.

The surprise, discussed as part of the wash up afterwards, was the 3 tonne hole in the fuel plan options they thought they had with a useless engine plodding away alongside them as a very large, thirsty APU.

Rob

[ekolbregit]

I'm happy to be wrong. I just referenced CAO 82.0. Perhaps CAO 26 trumps COA 82. I'm not sure.
Please show me the references.
When an ETOPS airport becomes unavailable during cruise, we always had 3 options: turn around, divert to remain in ETOPS coverage of an other available airport or land. Of course with 2 engines operating, and engine failure probabilities being low, we would most probably keep going if time intervals were reasonably insignificant.
Either way, here we are talking about a specific airport pair, both available, and what is or is not considered to be an acceptable risk.
Like I said, I deal with this a couple of times a month and my licence is on the line every time.
Perhaps I'm about to be re educated.

[compressor stall]

There is no time limit on a takeoff alternate in oz - unless your company mandates it. You just have to get somewhere else in any timeframe (less than max endurance!). Most other sensible states follow ICAO Annex 6 stating a 60 minute takeoff alternate if dept weather is cr@p.

If an EDTO airport went out in cruise - and you were already past your EEP, what states you have to divert to remain within three hours of another EDTO alternate? Why couldn't you just keep going?

And your EDTO area is predetermined by distance - not time. This is a common misconception. It is the distance travelled in a time (eg 180mins) at a predetermined speed and weight. For arguments sake, let's assume your EDTO threshold is 1300nm @ 180 mins. You can now fly up to 1300nm from your nominated EDTO aerodrome, irrespective of winds. If then you had a 100kt headwind for the divert, you'd end up taking 234 mins to get there. Totally legal under the regulations. Of course your EDTO xtra fuel on your plan would be significant.

[ekolbregit]

Compressor Stall.

In my first post I mentioned the take-off alternate was required if the departure airport was closed to arrivals. Fair enough regarding Oz. I've not worked there for some time. It was the general principle of a take-off alternate, Australia excluded.

In the last post I apologise for my lack of clarity. I said "Of course with 2 engines operating, and engine failure probabilities being low, we would most probably keep going if time intervals were reasonably insignificant". I meant being already inside the ETOPS threshold for the airport that became unavailable.

With regard to your last point, you may well be correct. ETOPS defines the total area of operation. One may well be able to choose one's preferred airport. But I wouldn't wish to expose my PAX and aircraft to the additional flight time on one engine in case something were to happen to the other one. That's where the probability and risk enter. I'd possibly be facing severe penalty if my judgement was wrong.

Certainly food for thought.

[waren9]

The surprise, discussed as part of the wash up afterwards, was the 3 tonne hole in the fuel plan options they thought they had with a useless engine plodding away alongside them as a very large, thirsty APU.

i wonder if in this case the fms started giving se fuel predictions?

[compressor stall]

But I wouldn't wish to expose my PAX and aircraft to the additional flight time on one engine in case something were to happen to the other one. That's where the probability and risk enter. I'd possibly be facing severe penalty if my judgement was wrong.

If your EDTO area of operation was 1300nm on your aircraft (180mins OEI)and you were flying between two island EDTO alternates 2599nm apart with no others around would you go?

What about if you had a 150kt crosswind all the way there or back?

Is there a difference, legally? Operationally?

[Icarus2001]

etp and cp have different definitions.

suggest you reword your post to get the discussion you are fishing for

Can you elaborate a little? I have been searching.:confused:

[waren9]

a critical point or pnr (point of no return) is the last point you have fuel to divert or return to the airfield being considered

[Icarus2001]

a critical point or pnr (point of no return) is the last point you have fuel to divert or return to the airfield being considered

Waren I think you may be confusing the terms.

Critical Point or Equi-time point is where the TIME to two destinations is equal. It does not take into consideration fuel. It is all about TIME.

PNR is about how far one can fly, often from the departure airport but also can be an off track PNR, and still return to a nominated airport. PNR is all about FUEL which obviously translates to time in the air.

Because in aviation we are not happy unless we keep changing the name of things to suit the latest whim (AFIZ, MBZ, MTAF, non towered...) the acronym LPSD latest point of safe diversion is also used. I stuck with CP/ETP and PNR to KISS.

Am I missing something, happy to be wrong.

[waren9]

there is nothing necessarily critical about an etp unless you are on min fuel.

a pnr/cp is by definition always "critical"

perhaps just semantics

[Jet Man]

I agree Icarus, CP and ETP are synonymous as far as ETOPS/EDTO is concerned. PNR is something entirely different.

In reference to the original post. After the engine rolled back surely thrust was restored?

[Capn Bloggs]

a pnr/cp is by definition always "critical"

Warren, I'll say it also. "CP" is the point of equal time back and on in the middle of the flight, timewise. It is not the PNR, which is a totally different kettle of fish. The CP is also called the ETP.

the acronym LPSD latest point of safe diversion is also used.
Iccy, I have always considered that PNR and LPSD are different. LPSD is an offtrack PNR ie to a place off track. PNR, by definition, is the point of no return to the place of departure.

[oicur12.again]

I am returning to ETOPS flying shortly and have started studying (sort of) before line training kicks in but I find myself a little confused. Either some rules have changed or my memory is getting as bad as my eyesight……

If an en route airport becomes unavailable after the EEP, re route or turn back is NOT required?

“Weather minima at diversion airport(s) going below the company/crew en-route minima, before reaching the ETOPS Entry Point, or diversion airport(s) becoming unsuitable for any reason.”

I read the above from FCOM as though we can continue if wx goes below landing mins after we pass the EEP? Does the same apply to the remaining comment in the passage – “…or diversion airport(s) becoming unsuitable for any reason.”

Thanks for any input.

[The Green Goblin]

Etops is basically a planning exercise.

Once you dispatch you make the best decision you can with the available information and time available.

The end

[compressor stall]

Once you dispatch you make the best decision you can with the available information and time available.

The end


Not strictly true GG.

When you pass your EEP (EDTO Entry Point) it is as you say. Up until that point, however, if the weather deteriorated at your island divert - or you had a mechanical issue rendering you no longer EDTO compliant - you'd have to turn back.

It just so happens that many Australian airlines have chosen to pervert this regulation and declare their EEP as dispatch, not at 90 minutes out from the last suitable aerodrome which by strict definition is the beginning of the EDTO /ETOPS area.

The obvious commercial advantage is that if the weather is good when you takeoff at all your bolt holes across the Pacific then you can sail on your merry way to HNL, even if every one fogged in 2 mins later. Other airlines would reassess the bolt holes just prior to their EEP which might be halfway into the flight and if they have deteriorated below EDTO Alternate minima, then the flight can't continue on that basis.

[Icarus2001]

Iccy, I have always considered that PNR and LPSD are different. LPSD is an offtrack PNR ie to a place off track. PNR, by definition, is the point of no return to the place of departure. That sounds reasonable to me. I had a dig through some old notes and text books and came across the phrase "off track PNR" but LPSD works just as well.

A rose by any other name...

Etops is basically a planning exercise.
Once you dispatch you make the best decision you can with the available information and time available.

I tend to agree with this sort of KISS philosophy.

The important point in this incident is that it appears they had an engine operating at idle, thereby supplying services, versus an IFSD. Two different beasts. I look forward to reading more.

[DutchRoll]

When you say they turned back before the "CP", was this the CPE ("Critical Point ETOPs"), or was it the ETP (equi-time point)?

They are not the same thing.

An A330 CP (ETOPs) is calculated on simultaneous engine failure and depressurisation, which is the most fuel critical scenario. If you don't have both, the CP (ETOPs) becomes rather meaningless, not to mention that its calculation is a preflight requirement but not an inflight requirement. A cruise depressurised at 10,000ft with an engine out is not equal to a cruise at engine out cruise ceiling.

Now, they did not divert to the Marshall Islands (Majuro) but proceeded to to HNL:

For an A330 (at least in QF), Majuro is classed as a "Category C Airport". That is, it is only to be used as an "adequate" airport for the purposes of ETOPs planning. It is not an approved "Main" and it is not an approved "Alternate". In QF rules and regulations at least, it is stated crystal clearly that there is no requirement to land at the nearest adequate (i.e., a cat C) airport in the event of a critical systems failure.

The crew (at least if they were QF) were completely and totally within their rights to continue to Honolulu - and probably quite sensibly too. I've flown a lot into the remote Pacific airports and to force me to do it in an A330 the situation would want to be pretty grim.

**yes I'm qualified on the A330 in QF.

[AnQrKa]

Dutch

Interesting:

"In QF rules and regulations at least, it is stated crystal clearly that there is no requirement to land at the nearest adequate (i.e., a cat C) airport in the event of a critical systems failure."

I assume then that QF require a diversion to the nearest suitable airport in event of a major technical problem? How do QF differentiate between the two?

[DutchRoll]

I assume then that QF require a diversion to the nearest suitable airport in event of a major technical problem? How do QF differentiate between the two?
Correct.

A "suitable airport" is a Cat A or B airport which doesn't require an alternate, or for which the appropriate holding fuel is carried.

A Cat C airport (these are obviously different for various different aircraft types) cannot be a "suitable" airport. Thus Majuro can never be used as a "suitable" airport for diversion (for an A330).

Essentially by defining it this way, QF have said "yeah you could conceivably divert to a Cat C airport or an emergency airport if you really think you need to, but it's not the most desirable airport on account of a number of factors, so we're not going to force your hand". These pre-determined categories of course take into account the runways available, navigation aids, emergency services, lighting, and a bunch of other stuff.

QF also gives the Pilot in Command an out, in that he can do whatever he feels is necessary for the safety of the flight under the circumstances (except proceed past the nearest suitable), irrespective of all these definitions. But certainly in the incident described, there would be no rules or criteria broken at all by continuing to HNL. I think JQ operate by the same or similar principles.

[Jet Man]

Hey DutchRoll

What is the difference in fuel burn for DP and OEI DP for an A330. I know there's not a big difference on the T7. So at the end of a diversion out might not have a lot more fuel.

I know a lot of EDTO is a fuel planning exercise but if you are EDTO fuel critical and you're below flight plan fuel I think it's just airmanship to consider your options and make contingency plans, just part of being situationally aware.

[Ichiban]

In JQ, a Company Approved Adequate Airport does fall under the definition given of "Suitable Airport".

PKMJ, Majuro, is classified as a company approved, Category A, Adequate Airport.

[DutchRoll]

There's not a massive difference in F/F (a few hundred kg/hr), so yeah what you say may well be the case depending on the diversion time.

However that's nil wind. The wind can be markedly different at EO LRC ceiling (say, around FL250), and 10,000ft (in the depressurised case). This is the thing I've seen many guys ignore when they sweat on the CPE, which for the Bus assumes you're both single engine and depressurised, as if it's the same thing as an ETP with an engine failure but not depressurised.

I agree with your sentiment regarding contingency plans, etc. I wouldn't like going below the ETOPs flight plan fuel either (my attitude to fuel planning is certainly never going pave me a path to Management ;) ). It is planned that way to cover the worst case and if it's not your lucky day, you might need every drop of it!

Certainly in relation to the original post and the info we have, it doesn't seem the crew did anything untoward by continuing as they did. Christmas Island is a flight planned ETOPS adequate (Cat C airport) too, and honestly my A330 would have to be in a very serious condition to head to a tiny speck in the middle of a massive ocean in the dark of night (as QF and JQ flights to HNL are conducted) with one 2000m runway, a non-precision approach, PAL, no ATC, and landing on one engine. Majuro is similar, but marginally longer.

PKMJ, Majuro, is classified as a company approved, Category A, Adequate Airport.
Well that's an interesting difference! Strange that it can be considered cat A for a JQ A330, but cat C for a QF A330, especially when you look at the airfield and it's facilities. :confused: I mean, QF and JQ A330s are one and the same. As I say, I'm speaking from a QF perspective. What you just told me is weird.

[Jet Man]

Hi DutchRoll

My question was comparing DP with OEI DP (ie both at same altitude) so wind is irrelevant other than making the diversion quicker/longer. My rough calcs put the difference at about 800kg/hr for B777.

My point is that a lot of pilots say the chances of getting engine problem and depressurisation at the CP is minuscule, but that's not quite the case.

[Icarus2001]

My point is that a lot of pilots say the chances of getting engine problem and depressurisation at the CP is minuscule, but that's not quite the case.Could you post some examples to illustrate your point?

[stiffwing]

Dutchy
I agree
The categorisation of YMAV is another example of this 'disconnect' between JQ and QF
I'm sure the QF94 would prefer greater access to it ex LAX

[Jet Man]

Oops, missed a 0 on my last post, should be 800 not 80!

OEI only is somewhere in between but winds are different as has been pointed out.

Won't post specific examples. Glance at performance manuals should suffice.

[ernestkgann]

Jet man what do you reckon the actual likelihood of suffering an engine failure and a depressurisation, and being at 10 000' exactly at the CP is? How many times has it happened so far in the history of commercial jet flight?

[oicur12.again]

So in the QF case, lets assume for simplicity its CAVOK at all fields in the pacific.

Can a QF twin dispatch under EDTO using MAJ (for example) as an EDTO ERA, then suffer an engine failure over MAJ and the crew can elect to continue several hours to destination?

[stiffwing]

Yes. Cant proceed beyond nearest SUITABLE airport, as defined in ops manual.
(Maj is not a 'suitable' for this purpose)...

[AnQrKa]

What precludes MAJ from being deemed suitable by QF? Considering the CAVOK scenario mentioned above?

[stiffwing]

A conspiracy theorist might suggest that, if MAJ was a 'suitable' , then, under the QF rules, the PIC may feel more obligation to land there, (CAO 20.6 notwithstanding, as discussed in this thread)... I guess QF, like all other airlines, wants the a/c at the dest rather than another port.
The only reason that airports like MAJ (and PHTO and PLCH) are even up for discussion is to be able to dispatch a two-holer from (say) SYD to HNL or west coast USA legally on the 180 ETOPS rule (A330). No-one wants or even envisages going there. IMHO, thats why they are categorised this way..

[Jet Man]

ernestkgann

Less than the chance of medical diversion
Less than the chance of an engine problem
Less than the chance of a depressurisation
etc ......

My point was to be aware of fuel state for other scenarios as well and don't just dismiss if you are below the CP fuel because of the minuscule chance of a OEI DP happening at the most critical point.

[Buckshot]

Not a huge margin for error!

Photos: - Aircraft Pictures | Airliners.net (http://www.airliners.net/photo//0521476/M/&sid=c10ac5908b7409556695490ff7311a73)

[LeadSled]

Folks,
In the early days of the B767, a QF 767-238 visited Majuro, for an "on the spot" proving of the "suitability".
Tootle pip!!

[Mstr Caution]

Isn't the logic of EDTO, that after a critical system failure the AOC approval requires an aircraft to land within the maximum diversion threshold of 3 hours?

Are you guys saying an aircraft can fly past an adequate or suitable airport (where it initially has enough fuel to divert to) and set course for it's destination single engine purely cause it has enough fuel?

What if the destination is more than 3 hours away and you get something like a cargo fire warning? After travelling a certain distance past the suitable or adequate airport single engine where there would then be insufficient fuel to return to the adequate or suitable airport with sufficient reserves (ie: the return suitable or adequate has a tempo weather requirement)

MC

[ekolbregit]

United Airlines fly to Majuro 3 days a week in a B737-800, so the airport is more than capable of handling an A330. RNAV approach both runways. As good as an ILS.

If the airport is classed as Cat C, not suitable, then why bother nominate it as an EDTO alternate. It's your licence. Why would you fly on one engine, further than you had to do so, over nothing but water.

The passengers wouldn't be happy if they knew they were being put at extra risk.

[Mstr Caution]

Im with you Ekolbreigit.

Its similar to departing an airport where the weather is below minimums for a return. An ETOPS dispatched aircraft (in Australia) requires an airport where weather is forecasted above Adequate dispatch minimums within the ETOPS maximum diversion threshold.

So why would someone become airborne and suffer a critical system failure only to continue to the destination, further than the ETOPS diversion threshold?

Its comparable to getting airborne in Sydney, choosing not to land in Williamstown or Richmond and continuing to Auckland.

[BuzzBox]

If the airport is classed as Cat C, not suitable, then why bother nominate it as an EDTO alternate. It's your licence. Why would you fly on one engine, further than you had to do so, over nothing but water.

I don't work for QF/JQ, but I'm guessing it goes something like this:

For ETOPS planning purposes, Majuro meets the legal requirements and is considered acceptable to be nominated as an enroute alternate. That is, if the s@#t hits the fan, the aircraft COULD land there if necessary. That doesn't mean it MUST go there. As stated previously, under Australia's CAOs (and QF/JQ rules apparently) there is no requirement to land at the nearest adequate airport if such action is deemed to be safe and operationally acceptable. That gives the commander much more leeway in deciding where to go in the event of a failure.

In a nutshell - Majuro isn't considered desirable ('suitable'?) as a diversion port and isn't approved as such by QF, however, it is 'adequate' and an aircraft could land there if the situation demands it.

[Jetsbest]

Williamstown is the dock area near the bay in Melbourne. Williamtown is the fighter base near Newcastle, and is shared by myriad civil traffic. :}:O

[Mstr Caution]

Jetsbest - My typo.

Further, I was of the understanding that AFTER a CRITICAL SYSTEM failure.

The maximum diversion distance or EDTO limit takes into account other system failures. So that in the event of the sH#t really hitting the fan the aircraft was within a reasonable range of an airport to land at.

The certification of maximum diversion distance limitations takes into account additional system features or failures such as:

Cargo Fire Suppression
Cargo Fire Hold (lining) containment
Propulsion on the remaining engine
Equipment Cooling
Ice protection Failures (should you be down single engine / depressurised picking up ice)

So its not only the initial critical system failure, but the what if's if something else fails later.

MC

[BuzzBox]

Isn't the logic of EDTO, that after a critical system failure the AOC approval requires an aircraft to land within the maximum diversion threshold of 3 hours?

So why would someone become airborne and suffer a critical system failure only to continue to the destination, further than the ETOPS diversion threshold?

I don't think anyone is suggesting that it's ok to continue past an enroute alternate (ERA) and fly further than the ETOPS/EDTO diversion threshold or rule distance (call it what you will!). However, it MIGHT be acceptable to continue past the CP/ETP for the nearest ERA and divert to the next ERA, if the more distant airfield is considered a better option and the operation is deemed safe. The distance to that airfield would obviously be one of the many factors that would need to be considered.

[waren9]

route distance limitation is derived at whatever speed is nominated for diversion and is nil wind.

at flight planning stage it is possible with wind forecasts allowed for to have a diversion time from an etp to airfield > 3hrs.

[milleroz]

Depends what the most critical case is. 1inop or DP.
I'd suggest 2 engines operating DP is the most critical

[waren9]

that depends on a/c type and weight

[neon123]

Anyone know why this occurrence is not listed on the ATSB safety investigations website?

[BGQ]

There is so much misinformation about ETOPS and EDTO in this thread and assuming those speaking "authoritatively" are currently pilots operating in the environment it brings into question the quality of the training being provided by some airlines.

[BGQ]

Potentially a B777-300 could be 5hr 39mins away from the EDTO alternate.

Area of operation is determined by 240 minutes at two engine cruise speed...

240 mins at 490 kits = 1960 nautical miles

1960 nm at ETP1D speed (Single engine depressurised @ FL140 = 5hrs 39 mins

I don't know if there are any potential routes where this might apply but....

[itsnotthatbloodyhard]

There is so much misinformation about ETOPS and EDTO in this thread and assuming those speaking "authoritatively" are currently pilots operating in the environment it brings into question the quality of the training being provided by some airlines.

Area of operation is determined by 240 minutes at two engine cruise speed...

If EDTO area of operation is based on 2-engine cruise speed, then you're right, it definitely brings into question the quality of training I received. And my outfit's manuals are so badly in error that CASA should probably just shut the whole joint down.

[compressor stall]

BGQ
There is so much misinformation about ETOPS and EDTO in this thread and assuming those speaking "authoritatively" are currently pilots operating in the environment it brings into question the quality of the training being provided by some airlines.

Area of operation is determined by 240 minutes at two engine cruise speed...


Really? Do you want to amend that before you get hung drawn and quartered here by the professionals?

[BGQ]

For maximum diversion times above 180 minutes there is a requirement to consider 2 cases.

(1) an area which is a function of the all engine operating cruise speed at normal cruise altitude, corrected for wind and temperature and the most limiting capability of the cargo and baggage compartment fire suppression system time minus 15 minutes.

(2) an area which is a function of the single engine inoperative cruise speed at driftdown altitude, corrected for wind and temperature and the most limiting system (not including cargo and baggage compartment fire suppression system) time minus 15 minutes.

Admittedly the second requirement would normally be the most limiting but the point is that diversion times can exceed the 120/180/240 mins

[compressor stall]

That one could exceed 120/180 was not in doubt here ?

You've made a critical opinion elucidated it with a statement (regarding a different ETOPS regulation for a different type of a/c) of fact, and when challenged then subsequently state that the reg that you didn't mention is the normal case. :confused:

It could be that I misread the intent of your post, rereading your last sentence on your middle post.

[haughtney1]

Potentially a B777-300 could be 5hr 39mins away from the EDTO alternate.

Area of operation is determined by 240 minutes at two engine cruise speed...

240 mins at 490 kits = 1960 nautical miles

1960 nm at ETP1D speed (Single engine depressurised @ FL140 = 5hrs 39 mins

Ummm really? (straight from an Ops manual)
"ETOPS is the acronym created by ICAO to describe the operation of
twin-engine turbine aircraft over a route that contains a point further than
60 minutes flying time from an Adequate Aerodrome, at the approved
single engine inoperative cruise speed (under still air ISA conditions).
ETOPS includes operations over remote land areas and water."

So yes you can exceed the time, but most likely due to the wind component. I'm not sure how you can define the area of operation (I'm assuming you mean the ETOPs segment) as being based on the normal 2 engine cruise speed, unless of course this is a local Oz variation.

[compressor stall]

Haughtey - I'm guessing your Ops Manual doesn't cover EDTO/ ETOPS greater than 180 minutes (admittedly not many would). Only that case are actual wind and temp are considered. Not unique to OZ (or NZ for that matter).

There are two (2) things to consider though :}

FAR 121 Appendix P (g) refers.

[haughtney1]

CS, yep it does, up to 207 minutes….all copy and pasted EASA stuff, with a local variation or 2.

ETOPS Fuel Requirements
Unlike the area of operation, which is determined in still air and ISA
conditions, fuel planning must consider the expected weather conditions
forecast en-route (wind component, ISA deviation, icing). For dispatch of
an aircraft under ETOPS, both the standard fuel planning (refer to
Section ****, and the ETOPS fuel planning must be calculated, and the
higher of the two uplifted.

ETOPS Fuel Planning

ETOPS fuel planning requires the calculation of Critical Fuel Reserves by
consideration of a Critical Fuel Scenario. This fuel planning is split into two
parts:
a. Standard fuel scenario from departure to the Critical ETP.
b. Critical Fuel Scenario from the Critical ETP to the diversion
aerodrome.
The Critical ETP is the ETP exhibiting the lowest fuel surplus or the
highest fuel deficit. The highest fuel deficit is considered to be the required
additional ETOPS fuel reserve.
If the ETOPS sector is covered by only one suitable aerodrome, the
critical fuel will be based on ENTRY and EXIT, and in most cases the latter
will be the most critical.

Critical Fuel Scenario

The ETOPS Critical Fuel Scenario is based on the study of three failure
cases, occurring at the Critical ETP, with their respective diversion profiles
and consequent fuel requirements. The fuel requirements for each of the
three failure cases are then compared to the standard fuel requirement,
and the highest quantity will be uplifted. This fuel uplift will then assure
safe completion of the flight, regardless of flight scenario (normal flight or
diversion).
The Critical Fuel Scenario is defined as follows:
a. Descent at the selected speed schedule to the required diversion
level.
b. Cruise at the selected diversion speed.
c. Normal descent to 1,500 ft above the diversion aerodrome.
d. 15 minutes holding.
e. First approach and missed approach as an instrument procedure.
f. Second approach and landing as a visual circuit.

Three separate failure cases must be considered as follows:
a. Engine Failure
1. Descent at the selected speed cruise to the selected level
schedule.
2. Diversion cruise at the selected level and speed.
b. Depressurisation
1. Emergency descent at Vmo/Mmo (speedbrakes extended)
down to FL100.
2. Diversion cruise performed at LRC speed.
c. Depressurisation and Engine Failure (Worst Case Scenario)
1. Emergency descent at Vmo/Mmo (speedbrakes extended)
down to FL100.
2. Diversion cruise at the selected speed schedule.

Additional Fuel Reserves

ETOPS requires that additional fuel be added to the fuel calculated in the
three cases above to allow for:
a. Contingency fuel – 5%.
b. Performance Factor for each individual aircraft.
c. APU fuel consumption.
d. Icing penalty – for total anti-ice (engine and wing) at 10,000 ft.
e. Effect of any MEL items.
f. Effect of any CDL items.
The OFP calculates the fuel requirements for the two engines
and single engine depressurised cases using the actual aircraft weight at
the Critical ETP, and automatically selects the higher of the two fuel
requirements (the single engine pressurised case is never limiting).
Contingency fuel, aircraft performance factor, and APU fuel consumption
are automatically calculated by the OFP. Icing, MEL/CDL penalties are
applied by dispatcher if required.

Pretty comprehensively covered and unambiguous…and fuel is the critical issue..always.

[compressor stall]

Interesting. Must be a regional variation. I'm not that up to speed with EASA regs but here's the FARs, -actually 121.633 (not the ref above).

(a) For ETOPS up to and including 180 minutes, no person may list an airport as an ETOPS Alternate Airport in a dispatch or flight release if the time needed to fly to that airport (at the approved one-engine inoperative cruise speed under standard conditions in still air) would exceed the approved time for the airplane's most limiting ETOPS Significant System (including the airplane's most limiting fire suppression system time for those cargo and baggage compartments required by regulation to have fire-suppression systems) minus 15 minutes.

(b) For ETOPS beyond 180 minutes, no person may list an airport as an ETOPS Alternate Airport in a dispatch or flight release if the time needed to fly to that airport:

(1) at the all engine operating cruise speed, corrected for wind and temperature, exceeds the airplane's most limiting fire suppression system time minus 15 minutes for those cargo and baggage compartments required by regulation to have fire suppression systems (except as provided in paragraph (c) of this section), or

(2) at the one-engine-inoperative cruise speed, corrected for wind and temperature, exceeds the airplane's most limiting ETOPS Significant System time (other than the airplane's most limiting fire suppression system time minus 15 minutes for those cargo and baggage compartments required by regulation to have fire-suppression systems).

(c) For turbine-engine powered airplanes with more than two engines, the certificate holder need not meet paragraph (b)(1) of this section until February 15, 2013.

[waren9]

i didnt know 777s had 5:39 worth of o2

[scrubba]

errhhh, why are we quoting FARs etc in this thread when we are supposedly talking about what applies in Oz?

Unless the relevant Oz rule specifically requires compliance with a particular FAR or EU rule, then quotation out of context is just misleading for those who suffer from PPRuNe Kool-Aid dependency... :ugh: :ugh: :ugh:

[BGQ]

Waren9

Some B777s have extra Oxygen bottles fitted. I would suggest that the Oxygen time limit would be determined by the number of passengers on board versus the available oxygen.

[BGQ]

Haughtney the 120/180/240 time is regularly exceeded. The TAS achieved in the critical fuel configuration is most often considerably slower than that used to establish the range circle or area of operation.

For example, the approved TAS for establishing range circles up to 180 mins on a B777-300 is approx 420 kts established at the nominated single engine cruise TAS.

The Critical Fuel scenario is normally ETP1D (single engine depressurised at FL140). The TAS in this configuration is considerably slower than 420kts

This is the most common reason for long diversion times.

As you say wind can also be a factor for exceeding the time.

[BGQ]

Haughtney your comprehensive post on EASA regs uses different words but mirrors closely the intent and requirements of those in Australia and NZ.

Not surprising.

[waren9]

crew o2 is dependant on pax oxy supply?

[BGQ]

I cannot verify this but I am informed by a B777 pilot that a standard crew bottle filled to maximum will last a three pilot crew 5 hrs +.

Maybe someone who flies one can verify

[compressor stall]

The Critical Fuel scenario is normally ETP1D (single engine depressurised at FL140)

Interesting - Never flown the triple, but on my type is generally fuel critical DP with two engines still turning at 10,000 feet (about 3.5% more fuel required than OEI).


oh, Scrubber - I quoted the FARs as we'd digressed to show it wasn't an Australianism - and there's an App for them; The rules are pretty much the same and it was much easier than trying to download and search in an appendix to a CAO in commlaw. CASA :mad:

[scrubba]

CS,

In that case, you (and the App) might be able to clarify something for me about O2 limitations.

From memory, the FARs allow the pax to be carted around DP at F140 without O2 (15-25 min OBOGS) but not FAs, who have to be supplied with O2 after 30 mins between F100 and F125 or at all times above F125 - is that still the case?

If it is, then I also believe that the FA O2 supply would be additional to the first aid oxy which is for the pax rather than the crew. My understanding is that first aid oxygen is like contingency fuel, in that you can't plan to use it for other than its primary purpose.

If all of that is true, do you know how operators carry enough O2 down the back to make the famous "DP @ F140" scenario work?

[I think those operators would be non-EU, since I think they state quite plainly that the DP scenario is at F100/10K']

[greybeard]

Here's one for new year.

Should you be at right angles to your track for it to be the CP?

How long at normal or S/E cruise at high altitude does it take to turn around??

Allow for a clearance, track incursions in crowded areas.

Where is the REAL CP?????

How much fun to fill in the cruise time to work that out so at the questions which will be asked in the event of.....

You can say "that's why I did>>>>>"

Happy new year if you can.

:ugh::ok:

[*Lancer*]

Firstly, oxygen is not an EDTO critical system. Obstacle clearance driftdown, escape routes, and oxygen endurance is a separate issue.

Secondly, the EDTO area is defined by the most limiting of the two cases, not the least limiting. For twin-engined aircraft, the most limiting area is usually the single-engined second case. For quad-engined aircraft, the most limiting area is usually the fire suppression first case. A 777 will not be 4+ hours from an available adequate airport, but a 747 might be.

Greybeard, the CP is a preflight calculation based on - largely arbitrary - data and regulations. The PNR is the inflight case based on what you calculate on the spot factoring in all your questions and decisions (what is actually happening).

Happy New Year! :ok:

[Jet Man]

Carrying more O2 can save you fuel if you are limited by the ETOPS/EDTO fuel though.

[scrubba]

Hey *Lancer*:

Firstly, oxygen is not an EDTO critical system. Obstacle clearance driftdown, escape routes, and oxygen endurance is a separate issue.

How separate? I would have thought that those issues were a subsequent filter on the overall EDTO route assessment, once the time/distance constraints were identified. :confused:

[*Lancer*]

Scrubba, for what purpose? There are minimum O2 quantities required for dispatch depending on crew/pax numbers, but only to facilitate descent to 10000'. Oxygen limited routes require more O2 simply because it takes longer to get to 10000' due to terrain.

Sure surplus oxygen may allow a different (to the flight-planned) driftdown/diversion strategy to conserve fuel, but this is an inflight consideration. O2 quantity isn't varied preflight to allow a reduction in fuel burn when CPD limited - more fuel is carried!

[BGQ]

Oxygen can be limiting in a two engine aircraft.... HKG-LHR would be a case in point.

There is a requirement for pax oxygen at FL140 but not at 10000ft.

It is up to the operator whether they carry the Oxygen for FL140 or just for descent to 10,000.

Clearly if terrain requirements necessitate the use of Oygen it must be considered.

[*Lancer*]

There is a requirement for fixed pax oxygen above 14000, and supplementary pax oxygen above 10000.

O2 quantity is definitely considered in FCOM/DDG, route requirements and design (L888 for example). If an operator wants to reduce CPD fuel and standardise diversions at 14000 to the limit of crew oxygen endurance, it will be based on a set minimum dispatch quantity (specified in FCOM/DDG).

In any case, it does not alter the EDTO area, it is considered separately. Happy to be corrected if I'm missing something! :)

[Prince Niccolo M]

Compressor stall or Lancer,

Understand that the EDTO area is unrelated to O2 in the first instance. But on the day, can you launch knowing that you have insufficient O2 on board to cover your contingency planning?

I think that was what raised the question about continuing depressurised at FL140 provided you had sufficient flight crew O2. I think the question that has been ignored is what O2 do the FAs need at FL140?

[billyt]

Lancer has it sorted.

[*Lancer*]

Prince Niccolo,

No you can't launch with less oxygen than what is required for dispatch.

At 14000' the FAs have access to portable oxygen bottles (supplementary oxygen) in accordance with CAO 20.4 8.6. The number of bottles available is determined by 8.8.

[Prince Niccolo M]

*Lancer*,

Serves me right for trying to clarify someone else's questions :(

So, we agree that you can't launch with less O2 than required for your plan.

We most certainly do not agree on the relationship between paragraphs 8.6 and 8.8 of CAO 20.4 := := :=

You said:

At 14000' the FAs have access to portable oxygen bottles (supplementary oxygen) in accordance with CAO 20.4 8.6. The number of bottles available is determined by 8.8.First, for the EDTO ops under discussion, the normal supplemental O2 is provided by plumbed in O2 bottles or OBOGS designed to cater for the depressurised descent to a cabin altitude of 10K', where after it is not required. Your basic OBOGS provides 15 minutes and most gaseous O2 tables tell you how much you need to provided the 10 mins for the pax, with the FAs generally being covered the same way. Keeping First Aid O2 out of it (it is a mutually exclusive requirement with a totally different flow rate specified), there are generally no portable O2 bottles on board. So a decision to fly a DP diversion above 10K' would require a conscious decision to add portable bottles suitable for the purpose.

Second, paragraph 8.8 is titled "Supplemental oxygen for passengers" and it is quite separate and distinct from the requirement set out in paragraph 8.6 which is titled "Supplemental oxygen for other crew members".

Now, for me the conundrum is this: how do you calculate the requirements of subparagraph 8.6(a), should you plan a DP diversion at FL139.99? :eek:

Unlike subparagraphs 8.6(b), 8.8(a)(i), 8.8(a)(ii) and 8.8(b) which are easily calculated, how much is enough when you merely need to provide a supply? :E

[*Lancer*]

Prince, I can assure you that supplemental oxygen is absolutely provided by portable oxygen bottles on many airliners (e.g. 767, 737, a320). Their fixed oxygen system is chemicallly generated and not capable of extended use. Aircraft with bottled emergency oxygen (e.g. 747, a380) still carry supplementary portable bottles.

Preflight, 'enough' supplementary oxygen is defined by the manufacturer, whereby the DDG may allow a reduction in accordance with the CAO 20.4 8.8 limit. Post dispatch, flight at 14000' is only limited by flight deck crew oxygen endurance. Bit of a thread drift, happy to chat over PM!

[BGQ]

Lancer,

Not all airliners use Oxygen generators for passenger Oxygen. Those that do would have to carry supplemental oxygen for flight at 14000.

Oxygen can be a limiting system on some routes. One operator ensures there is enough passenger O2 prior to departure for 4 hours flight at 14000. In terms of EDTO beyond 180 they assume flight beyond 3 hours 45 will be at 10000ft (4:00 hrs minus 15 mins)