4 engines, one fail. Go, no go?

[TO MEMO]

Hi guys,

Not trying to bring the BA flight LAX-LHR on 3 engine, but I`m just wondering those of you flying 4 engines, what are your company SOPs in regards to flying with one engine out.

Thank you

[alextop]

SOP is to land as soon as possible!

[Rainboe]

Well I've flown 747s around on 3 engines quite happily. I do not believe 'land as soon as possible' is sensible or desirable. But you know what a can of worms this is opening! I would rather be in a 747 on 3 engines than any twins or trijets with all engines working! Until you know a 747, you cannot criticise it. But there are many factors to weigh up: weather, alternates, fuel reserves, spare engines, maintenance capabilities. It's not just a yes/no decision. Anyone who is interested can dig up the old BA thread!

[Phil Squares]

Have to agree with Rainboe. I have flown both the Classics and 400 around on 3 and it's not a big deal at all. I would say doing an overweight landing or a rejected takeoff at MTOW close to V1 presents more risks than flying on 3 engines.

But again, it depends on the situation. However, with all things being equal, I'd continue on 3!!!

[Jumbo Driver]

It is certainly not to land at nearest suitable airport. That is the requirement of the twinjet - and for obvious reasons. It is absolutely not required on a 747 as there is so much system redundancy available. Each situation should be considered on its merits. In 23 years on the 747 (Classic and -400), I have had several in-flight shutdowns - none were significant events - and in two cases we continued on to destination.

I'm very much with Rainboe on this one ...

JD
:)

[barit1]

But again, it depends on the situation. However, with all things being equal, I'd continue on 3!!!

As Phil Squares says, it depends on the situation. If you have a dozen suitable alternates enroute, and the system redundancy of the airplane is 747-like, and your home base staff deems it a good plan, then sally forth.

That said, I hope you'd never second-guess he captain's judgement - go or return..

[A Comfy Chair]

I agree with Rainboe that it is not a simple decision. I might be one of the conservative ones, but I'm still all for landing in a reasonably short timeframe.

The 747 does fly excellently on 3 engines, and for that reason I agree that I wouldn't be considering landing overweight, or necessarily at the nearest airport, but at the nearest "practical" airport. Would I fly past a company destination airport that is able to take my aircraft size? No. Others might. Thats their decision. To qualify that, the routes I flew on the 747 were ones with very few airports that you'd want to go to close by, and some with reasonable terrain issues... so that probably biases me in the land direction.

Phil... I'm not sure why you think that rejecting close to V1 with an engine failure would be more risky than continuing... expecially if your V1 was calculated to be the minimum "Go" speed, not the maximum stop speed!

[TO MEMO]

Thank you guys!

I see that 747 drivers are pretty much go minded! How about 340 drivers?

[Karl Bamforth]

So how does a 747 fly on two ? How does it fly with 2 out on the same side.

[boeingboy737]

I think alot of folks might be missing the point sure it will fly around on 3 engines BUT I think if you look to the bigger issue with regards to Regulatory compliance if you have an engine failure Im pretty sure it dont matter if its on a 1,2 3,4, or 8 engine jet. if you are carring pax you are supposed to land at neariest airport. cant find the reg at this moment ill have to look it up I would land!

[Jumbo Driver]

Phil... I'm not sure why you think that rejecting close to V1 with an engine failure would be more risky than continuing... expecially if your V1 was calculated to be the minimum "Go" speed, not the maximum stop speed!

A heavyweight rejected take-off on a 747 at or close to V1 involves considerable energy absorption and should not be undertaken lightly. Stopping around 380 tonnes using heavy braking will at the very least generate considerable heat in the brakes and tyres - including blowing some fusible plugs - and I can assure you this focuses the mind somewhat as you taxy off the runway (if you can!), usually at the far end. Add to that the problem that prompted you to reject the take-off in the first place and you will have quite a lot to consider in a short space of time. If you can take the problem into the air and give yourself a more relaxed approach to the problem, as well as the decided advantage of a more normal deceleration, using the whole runway, it may well be a far better option in my opinion.

if you are carring pax you are supposed to land at neariest airport. cant find the reg at this moment ill have to look it up I would land! This is not correct - either in USA or UK. The requirement only applies to the twinjets. As far as USA is concerned, I would refer you to FARs (para (b) below being the most relevant), which say:

Sec. 121.565 - Engine inoperative: Landing; reporting.

(a) Except as provided in paragraph (b) of this section, whenever an engine of an airplane fails or whenever the rotation of an engine is stopped to prevent possible damage, the pilot in command shall land the airplane at the nearest suitable airport, in point of time, at which a safe landing can be made.

(b) If not more than one engine of an airplane that has three or more engines fails or its rotation is stopped, the pilot in command may proceed to an airport that he selects if, after considering the following, he decides that proceeding to that airport is as safe as landing at the nearest suitable airport:

(1) The nature of the malfunction and the possible mechanical difficulties that may occur if flight is continued.
(2) The altitude, weight, and usable fuel at the time of engine stoppage.
(3) The weather conditions en route and at possible landing points.
(4) The air traffic congestion.
(5) The kind of terrain.
(6) His familiarity with the airport to be used.




JD
:)

[mutt]

cant find the reg at this moment ill have to look it up I would land! We will wait patiently until you find that regulation!

Its interesting to see that those who operate the aircraft say they would assess the situation and make a decision, those who know nothing about the aircraft say land ASAP!

IIRC the longest that we have continued a B744 following an IFSD was 6 hours! Totally legally under the FAR's as quoted above.

Mutt

[Capt Claret]

BUT I think if you look to the bigger issue with regards to Regulatory compliance if you have an engine failure Im pretty sure it dont matter if its on a 1,2 3,4, or 8 engine jet. if you are carring pax you are supposed to land at neariest airport

Australian CAO 20.6 says otherwise.

2 APPLICATION

This section applies to all Australian aircraft.

3 REQUIREMENTS

3.1 When an engine of an aircraft fails in flight or where the rotation of an engine of an aircraft is stopped in flight as a precautionary measure to prevent possible damage, the pilot in command shall notify the nearest Air Traffic Services Unit immediately, giving all relevant information and stating the action he or she intends to take in regard to the conduct of the flight.

3.2 The pilot in command of a multi-engine aircraft in which 1 engine fails or the rotation thereof 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. These factors shall include the following:

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

(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;

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

Issue 4: 8 December 2004

[411A]

IIRC the longest that we have continued a B744 following an IFSD was 6 hours! Totally legally under the FAR's as quoted above

Indeed so, it most certainly is.
The same is true for my three engine airplane.
However, we should remember that these regulations were originally designed for the enroute IFSD situation.
To apply them to a takeoff situation, followed by a very long overwater sector, with limited enroute alternates is, in my opinion, stretching the (legal) regulations just a tad thin.

[TopBunk]

So how does a 747 fly on two ? How does it fly with 2 out on the same side.

It flies just fine. Some procedural differences on approach for us relating to sterile runways, commital points etc, but it flies nicely. Obviously it is not designed to take off with 2 failed or failing, but even at high weights, once you get to a couple of thousand feet and flaps to 5 or 1 cleaning up you will generally be ok.

I doubt you would be able to say the above with 2 failed on a Tristar on A340-300:}

[A Comfy Chair]

JumboDriver,

I think you might have missed my point. These days, everyone is "go" minded, which I agree is a good thing.
I fully agree that there are risks associated with high energy stops.

If we're talking a couple of knots short of V1, then yes, you'll end up continuing because you won't have started the stopping action in time.

I am also aware, however, that if your V1 is based on your minimum engine out "Go" speed, to attempt a continued take off below that speed could be more dangerous than stopping! The point is that engine out below a minimum "go" V1 you will either not meet your screen height at the end of the runway (which is only 35ft anyway), or you won't meet the required climb gradients in the second segment. Not a situation I'd like to be taking into the air to sort out!

Topbunk, yes it flies ok on two... although on takeoff at 397 tonne I'm not sure I'd be saying that! A big catch is the 18,000 odd max performance altitude limit that causes problems with 20,000ft safety heights ;)

[Jumbo Driver]

A Comfy Chair, sorry if I missed your point - I was trying to help - perhaps I should have left it to Phil S to answer, after all it was to him you posed the question.

However, I think to a large degree you have now answered your own question. Any attempt to continue the take-off with a power failure below V1 has the potential for disaster. Typically, a reject close to V1 (especially when heavy) will only be called for a fire warning, engine failure, configuration warning or predictive windshear - most other events will be better carried into the air. Multiple failures or external circumstances such as an obstructed runway may also of course dictate a reject. The chance that VMCG will not have been achieved if you reject below V1 is also a possibility - but I will leave further discussion about the thorny subject of the relationship between VMCG and VMCA and V1/VR/V2 to those techies far better qualified than me to express an opinion!

As you will know, it goes without saying that critical decisions in circumstances such as we are discussing are ultimately what Command responsibility is all about. ;)


JD
:)

[tournesol]

If I may add, the B747 is also certified for initiating a take off with an engine out. This is a special procedure that is sometimes performed by different operators.
This obviously is for positioning the aircraft where repairs could be made, i.e. NO Revenue flt.
So if it is capabel of taking off on 3 engines it should be capable of continuing on 3 engs provided all the considerations cited in previous reply are considered.
:)

[Checkboard]

The performance for FAR 25 (or equivalent) aircraft is based upon a guarantee that the aricraft can keep flying if an engine fails at any point of the flight.

This performance guarantee only became possible with the advent of jet engines, and their excess of power at low (i.e. take-off) altitudes. Compare the regs for FAR 25 aircraft with FAR 23 - no guarantees for an engine failure in a Piper Navajo!

If you have a FAR 25 aircraft with more than two engines then continuing is always possible - provided you can give the passengers the same guarantee. That is: if you now lose the most critical remaining engine, you can guarantee the aircraft's performance - the big advantage is that (being airborne already) the most performance critical time (take-off) doesn't have to be taken into consideration.

SO, the engine fails (and you are making these decisions airborne of course):
Satisfy yourself that the failure is an isolated one. If the techlog mentions that all of the oil pressure sensors were changed over night, and you have just shut down an engine for low oil pressure, it is time to land!
On the decision to continue - check that you can have enough fuel to complete the trip at the lower level and new winds, with the reduced number of engines.
Check that you have sufficient fuel to divert, following a failure of the most critical engine at the most limiting CP [critical point]
Check that you can maintain above the lowest safe altitude, following a failure of the most critical engine at any point along the route, or perform a safe drift-down.
Check the reduced Go-Around weight limit, assuming a critical failure on the approach, and increase the approach minima as required.


Provided all of the above is completed, then the aircraft is perfectly safe to complete the route, flying as a "three engined" aircraft instead of as a four engined one.

Now those performance calculations should all be within the ability of any competent crew on board the aircraft, however it would always pay to radio the raw data to the airline performance department (should you have one!) to have the calculations cross-checked by someone relaxing on the ground.

[BelArgUSA]

With PanAm, we had spare engines available at strategic locations.
If no spare engine, we had agreement with other airlines etc.
We also had potentially spare airplanes available for the convenience of passengers.
Trying to minimize delays, and problems for hotels and connecting flights.
xxx
Of course, the final decision as to what and where was with the captain.
But we had to call operations, discuss the situation and options, and take the best.
However, I doubt PanAm did continue for an oceanic flight and destination 10 hrs away.
The 747 is ok on 3 engines, if another fails same side, still ok, but requires landing nearest suitable airport.
xxx
I do engine-out ferries on 747, I have done 3 of them in my career.
There is no V1 speed per se on a 3 engine ferry.
You pray your 3 engines are ok to reach Vmca-2 (160 Kts) and 400' AGL.
Engine-out ferries training is part of our normal recurrent simulator training.
Most captains are qualified to do engine-out ferries, our airline policy.
xxx
:8
Happy contrails

[A Comfy Chair]

JumboDriver,

Sorry if that sounded a bit blunt, I must admit I was a bit quick off the blocks, as these days there have been so many people pressing the "go" case that sometimes some of the "anti-go" reasons (like, as you point out, VMCG/VMCA) seem to be drowned out. Continuing a take off from 15kts prior to V1 because you can carry the problem into the air is one thing... but not actually getting off the runway is an entirely different one :}

The discussion as to if pilots should consider in what way V1 is limiting on a certain day is one can of worms I don't want to open. The relationship between the speeds is something I too will stay away from... someone with a much larger brain than mine is required to debate that one. ;)

I agree with you 100% that this is what command decision making is all about. I'd much rather have the captain to be able to make the call and continue than some rule maker stipulate you must land ASAP.

As to 3 engine ferries... as BelArgUSA points out, they are approved... although the 3 major airlines I have any knowledge about all prohibit 3 engine ferries on their aircraft, with the preference being to taking a spare to the aircraft, rather than the aircraft to the spare.

I've recently moved to a 2 engine aircraft, so I guess I can happily continue on my "land soon" way without causing a fuss :E

[Pugilistic Animus]

91.7 Civil aircraft airworthiness.
(a) No person may operate a civil aircraft unless it is in an airworthy condition.
(b) The pilot in command of a civil aircraft is responsible for determining whether that aircraft is in condition for safe flight. The pilot in command shall discontinue the flight when unairworthy mechanical, electrical, or structural conditions occur.


in the US--that means land, as soon as practicable to me--never flew a four engine craft---[check the history of FAA prosecutions]----then offload the pax-- obtain a waiver--and then ferry the aircraft legally and safely on three---or---the FAA will say--

§ 91.13 Careless or reckless operation.

(a) Aircraft operations for the purpose of air navigation. No person may operate an aircraft in a careless or reckless manner so as to endanger the life or property of another.
(b) Aircraft operations other than for the purpose of air navigation. No person may operate an aircraft, other than for the purpose of air navigation, on any part of the surface of an airport used by aircraft for air commerce (including areas used by those aircraft for receiving or discharging persons or cargo), in a careless or reckless manner so as to endanger the life or property of another.


just lately the FEDs have been in a very bad mood-:\

PA----:ouch:

[barit1]

Compare the regs for FAR 25 aircraft with FAR 23 - no guarantees for an engine failure in a Piper Navajo!

Here's a case of attempted TO continuance after engine failure in a PA-31 - He must have thought he was in a 747:

DCA80AA002 (http://www.ntsb.gov/ntsb/brief.asp?ev_id=34515&key=0#)

BTW he had plenty of r/w remaining.

[barit1]

If I may add, the B747 is also certified for initiating a take off with an engine out. This is a special procedure that is sometimes performed by different operators.
This obviously is for positioning the aircraft where repairs could be made, i.e. NO Revenue flt.

This is a special AFM chapter, special inspections, procedures, limitations and training...

And it dates back to the DC-6. I believe almost all 3- and 4-engine transports have this certification, although the operator may have to pay extra for the rights.

[411A]

The performance for FAR 25 (or equivalent) aircraft is based upon a guarantee that the aricraft can keep flying if an engine fails at any point of the flight.

This performance guarantee only became possible with the advent of jet engines, and their excess of power at low (i.e. take-off) altitudes.

I'm terribly sorry, Checkboard, but that is simply not true.
CAR4b regulated the required performance of 4-engine piston types, and I can assure you that these were fully capable as well, for three engine continued flight.

I should know, I flew enough of 'em to find out, first hand.
DC-7, especially.:}

[lomapaseo]

I'm glad to see that this has been a calmer thread then the BA 3 engine flight of a year or so ago.

It looks like a good job so far of sorting out the safety related regulatory issues which seeem to put the knowgeable pilot in charge of rational decision making seeing as there are many considerations at play.

I had mentioned in that earlier thread that crew workload during landing should be at least one of the major considerations if an alternate airport were chosen. An engine out during flight is well trained. The larger concerns in the historical data base have been with landing. Adding in to this with an unfamiliar airport makes this a more critical consideration in decision making.

However I am drawn back to the original question from the initiating thread post.

Do we really have a lot of variance in the SOPs between operators?


Hi guys,

Not trying to bring the BA flight LAX-LHR on 3 engine, but I`m just wondering those of you flying 4 engines, what are your company SOPs in regards to flying with one engine out.

Thank you

[BelArgUSA]

Lomapaseo -
xxx
Well, I am unfortunately not as qualified as BA pilots...
And my 747 has not been maintained as well.
xxx
Would the BA situation have happened 20 years ago, with PanAm... (SFO-LHR)
(1) The 747 would have continued to ORD or JFK, on 3 engines. Plenty airports between SFO-JFK.
(2) Captain would have made a PA advising pax of unscheduled stop.
(3) PanAm would have had a spare 747 ready with fresh crew at JFK.
(4) That is the safest and most acceptable operational considerations.
(5) It would have been the joint decision of captain and dispatch.
xxx
Of course, PanAm pax would have incurred late LHR arrival (3 or 4 hrs).
Darn Yanks... they cannot run on-time operations.
:*
Happy contrails

[chornedsnorkack]

So, 4 engined planes can take off for engine out ferry. They are not allowed to do so with passenger payloads, they do so with light loads, but they can do it. Actually, 3 engine planes can do the same - and in the way they operate, there have been actual cases of 3 engine planes like Tristars starting takeoff with 2 engines, losing one of the remaining engines during takeoff, climbing out on one engine and successfully returning to airport. And I understand that every 3 and 4 engine plane is supposed to be capable of climbing out of takeoff with 2 engines out, at ferry loads, after starting takeoff with 1 engine out.

Then what is the "minimum Go" V1 about? Are airplanes commonly in situation where they are able to Go with one engine loss early in takeoff?

[boeingboy737]

I stand corrected!! thanks for the info to all who posted. being a two engine guy it is land at nearest airport. regards and happy and safe flying

[TopBunk]

BelArg

What happened 20 years ago in another lifetime is one thing (and mostly irrelevant nowadays). BA used to have spare engines dotted about the network as well, but don't nowadays (as I'm sure applies to many other carriers). This is mainly because of engine developments and monitoring technology rendering it unnecessary. Only last week in the in-house weekly paper I read that one of our 747-400s had just had an engine change. Nothing unusual in that, I hear you say. Exactly, but it had been 'on the wing' since delivery from Boeing in about 1997!

Yes, you read correctly - over 10 years and over 40,000 hours. The average (iirc) is over 25,000 hours on the wing.

ChornedSnack

Re 'min Go v1': Airlines can determine v1 on a variety of parameters. They include v1 which uses maximum stopping capabilities where the aircraft will only just stop on the paved surface (may be used to maximise payload for example) and the minimum Go v1, which is the point a which a failure still gives sufficient runway to reach take off speed.

As an example, a shorthaul aircraft taking off from a 4000m runway would only need about 1500m or so, it could accelerate to about 250kts and still stop (in the max v1 case) but that is pointless.

[mutt]

Pugilistic Animus,

Thank you for quoting FAR91. As one of the few operators who operates B747 aircraft under FAR91, we would not consider an engine failure to have made the aircraft unairworthy, therefore the flight would continue. In fact, one of the main reasons for buying 4 engined VVIP aircraft is to ensure that we dont land!

Mutt

[Jumbo Driver]

Pugilistic Animus, IMHO that (http://www.pprune.org/tech-log/348823-4-engines-one-fail-go-no-go-2.html#post4491507) really is an inappropriate and totally irrelevant post.


JD
:)

[Carnage Matey!]

Have the Feds ever prosecuted someone for continuing on 3 in a manner approved by the Feds?:confused:

[RB Thruster]

Nice to see the RB211-524 getting a mention. An era has just ended actually, with the delivery of the very last RB211 powered 747F to Cargolux. Various marks in production for around 30 years.:ok::D

On the 3 engine discussion, does the 747-400 have a lot more "spare" thrust than earlier -100 and -200s, or does the increase in max take off weight mean the later variant is similar?

RB

[chornedsnorkack]

What are 747-s doing under Part 91? They clearly have over 2700 kg payload capability, so that should be Part 125?

Also, for the people who want 4 engined VVIP planes, A340, A380 and Il-96 are obvious alternatives. How much spare thrust do they have for the case of one or two engines inoperative?

[Pugilistic Animus]

b) If not more than one engine of an airplane that has three or more engines fails or is shut down to prevent possible damage, the pilot-in-command may proceed to an airport that the pilot selects if, after considering the following, the pilot makes a reasonable decision that proceeding to that airport is as safe as landing at the nearest suitable airport:
(1) The nature of the malfunction and the possible mechanical difficulties that may occur if flight is continued.
(2) The altitude, weight, and useable fuel at the time that the engine is shutdown
(3) The weather conditions en route and at possible landing points.---low fuel:confused:
(4) The air traffic congestion.
(5) The kind of terrain.---oceanic/polar flight:\
(6) His familiarity with the airport to be used.--ok
(c) The pilot-in-command must report each engine shutdown in flight to the appropriate communication facility as soon as practicable and must keep that facility fully informed of the progress of the flight.
(d) If the pilot in command lands at an airport other than the nearest suitable airport, in point of time, he or she shall (upon completing the trip) send a written report, in duplicate, to his or her director of operations stating the reasons for determining that the selection of an airport, other than the nearest airport, was as safe a course of action as landing at the nearest suitable airport. The director of operations shall, within 10 days after the pilot returns to his or her home base, send a copy of this report with the director of operation's comments to the certificate-holding district office.---so they can pin all the blame on you!!!!

§ 91.611 Authorization for ferry flight with one engine inoperative.

(a) General. The holder of an air carrier operating certificate or an operating certificate issued under part 125 may conduct a ferry flight of a four-engine airplane or a turbine-engine-powered airplane equipped with three engines, with one engine inoperative, to a base for the purpose of repairing that engine subject to the following:..............................................,5) Persons other than required flight crewmembers shall not be carried during the flight.


RB-I saw you'd already posted 121, but didn't include part D--it's not irrlevant :=--read between the lines

part 91 applies to all pilots:O:O:O--91.3 IS the BEST example, as well as 91.13!!!

as far as prosecution--well almost they DID try-no?

and furthermore many criteria have to be assured and if they aren't then you broke the law--that's the ADMINISTRATOR:E---

I think BelArgUSA has the BEST answer--and it's very conservative:ok:

oh--I said I never flew a four engine jet I never commanded one:O--I do have the 707 rating and about 15 hrs RHS before they switched planes on me--it was free:}

[BelArgUSA]

FAR Part 91 applies to ALL operations... including "121", "125" and "135" as well.
The "VIP" 747 could not be under a Part 125 if operated under foreign, non-US certificate.
So, FAR 91 "Subpart D" applies.
xxx
:)
Happy contrails

[galaxy flyer]

Perhaps not all that useful, but USAF has for a long wanted 4-engines for the reason of being able to "carry on". We could in airlift continue past a divert with OEI, if no compounding problems had resulted, performance was considered, etc. Then on Xmas Eve, some crew shutdown an engine just airborne off Mildenhall, proceeded home to US. A little sheepish, they logged it as having been shutdown on descent. Well, the maintenance recorder caught 'em! Doh! Taken in shackles, and the rules were rewritten. I have used that the authority several times and agree that any of the four-engine steeds is completely airworthy with one shutdown, if it was "clean" shutdown and all other systems are operable. Crossing any ocean, not so much.

GF

[Rainboe]

So I guess when a B52 loses one out of the eight, it has to land as soon as practicable? Funny rules. But we did establish before that as the US operates mainly twins in competition with foreign airlines 4 engine jets, it does take away the competetive advantage of the foreigners if you absurdly make them obey the same rules as for twin engined aeroplanes! Moi, cynical?

[barit1]

All else being equal, twice as many engines means twice the chance of engine failure. :}

[Roadtrip]

It depends. If you have an engine failure and you think there may be internal mechanical damage (follow the QRH), you probably want to land before you tear up the engine anymore or worse, create an imbalance that causes destructive vibration. Further, it's likely you won't have the fuel to make it to the final destination due to the drag of the inop engine and the requirement to fly lower altitudes. While you probably won't make destination, you can get the company to pick out a convenient airport where maintenance and parts are available, not to mention a good long layover hotel with a beach and pretty girls.

[galaxy flyer]

Quite agree, Mr Rainboe. This has done before, but the FAA is so twin-centric; no one knows how 4-engine planes should be operated so they just apply the rules they know. (the short-sighted, know nothing idea) OR the cynical version, why let those furriners get away 4-engine ops.

The AF rule within the transport types-the bombers could depart on non-combat missions with one out, I believe.

[Rainboe]

....not if the FAA ruled military ops!

Funnily enough, I expect the B52 would be more efficient if it shut down 4 engines and operated 4 at high power? Maybe 2 shut down?

[PantLoad]

What does JAA say about this...comparing to FAA 121?

It's my intrepretation of FAA 121 that the aircraft need not be landed at the nearest suitable airport in point of time IF those six criteria are satisfied. It is NOT intended that the aircraft be flown for another ten or twelve hours (over the ocean, etc.).

I am not familiar with JAA regs in this regard, so someone please educate me. I don't have any four-engine time, but I have some three-engine time.

Fly safe,

PantLoad

[chornedsnorkack]

Doesn´t Nimrod have a SOP of shutting down two engines just to save fuel?

Would any civilian planes find it useful to follow suit? Starting with Comet itself...

[finncapt]

We didn't shut them down but, at light weights and holding at high levels, I seem to recall the VC10 was more efficient if 2 were throttled back and 2 were at a high power setting.

[Semu]

I believe the original post pertained to three engine ferries. At our company, they are performed by all check airman, who are all three engine qualified, and have to have done a relevant sim run in the last year (I think). Though I am not a check airman, I rode support for one regaining his three engine currency recently, and it was quite entertaining. Our numbers for a three engine dispatch are actually predicated on doing the whole takeoff on two engines, which it will do just fine, though you may need a proctologist to find the seat cushion. There is no V1 speed, or rather it is always VR, and so is dropped. Of course you want superb weather, daylight, correctly aligned stars and anything else you can think off. We actually have a couple of check airman who like doing them:eek:.

[Jumbo Driver]

... I seem to recall the VC10 was more efficient if 2 were throttled back and 2 were at a high power setting.

My recollection is that the Queen of the Skies was more economical on three - i.e. with one engine actually shut down ! :ok:

JD
:)

[411A]

Would any civilian planes find it useful to follow suit? Starting with Comet itself...

This was tried many years ago
Dan Air asked the ARB (yes, that long ago, ARB) if it was permitted.
The ARB replied...NO.

End of discussion.
I believe David Davies was involved, and he shot the idea down.

With good reason, IMO.