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]

Originally Posted by A Comfy Chair

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.

Originally Posted by boeingboy737

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]

Originally Posted by boeongboy737

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):

1. 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!
2. 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.
3. Check that you have sufficient fuel to divert, following a failure of the most critical engine at the most limiting CP [critical point]
4. 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.
5. 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]

Engine-out procedures

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

Happy contrails