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parkaboy
12th Aug 2011, 08:20
Greetings, I hope I have the right forum and please excuse any inaccuracies in terminology.

I am interested to know the procedure for take-off when ferrying a four-engine aircraft with one engine inoperable. I have read a little about one airlines procedure of applying max thrust to the two symmetric engines and derating the odd engine and manually bringing up that engines thrust to max during take off.

How does this work in practice? Is there any automated procedure for doing an asymmetric derate in such situations?

Cough
12th Aug 2011, 09:37
Nope, its just as you say.

Nothing automated, just a bit of pilot skill/training...

renard
12th Aug 2011, 11:06
On an RJ100, the basic procudure was:

Use max thrust - no derating

On runway, brakes set, set full power on the asymmetric engine and mak a pencil mark on the quadrant, so you can set full power easily when you take off. Reduce the thrust to 50%N1.

Set full power on the two symmetric engines.

Release brakes.

When at 60kts set full power on the asymetric engine - any earlier and you will not be able to maintain directional control.

Some limitations were

1600m viz and 1000ft ceiling at depature destination at alternates.

Max crosswind 10kts.

Whenwe
12th Aug 2011, 11:46
Have done a few in turbo props and the procedures outline already, all correct.

To make life a little easier; when at Vr don't rush it, plenty of runway ahead and lift the wing into the good engines about 5 degrees. It will help a lot with directional control.
Enjoy it, I did.

itsresidualmate
12th Aug 2011, 12:30
As a 146/RJ LAE and having fitted numerous lock out kits to a knacked engine, I was always curious what would happen if you lost the other good engine on the same wing as the u/s one on take off? Because Sod's law says that's the engine that would take the flock of seagulls! Once you're commited to take off, would you keep control easily enough if you only had two engines on the same wing?

Non Zero
12th Aug 2011, 12:33
What kind of 4 eng airplane you need to ferry?

Meikleour
12th Aug 2011, 12:40
I had the dubious pleasure of conducting a 3-eng ferry flight on a Vanguard (VC9) in the early `70s.
There were quite a number of different performance considerations eg. 2-eng inop. climb + VMCA2
The procedure was, as others have stated, basically full power against the brakes on the SYMMETRICAL ENGINES. Then a lower power on the "third" engine - followed by brakes off and the power from the "third" engine fed in progressively as speed is gained. Obviously with a much higher Vmcg used. I seem to remember ( I think ) that there was no V1 as such.

Much later in life I did undertake 3-eng ferry simulator training for the B747 but never did one in anger.

With the advent of wide body freighter aircraft which could carry spare engines the procedure would appear to be much less common.

Of historical interest: many 3 and 4 engined aircraft were fitted with an underwing "hardpoint" for carrying a spare engine. I have even seen a VC10 with a 5th engine podded under its wing - most strange sight!!

parkaboy
12th Aug 2011, 12:44
Many thanks to all. This is just the information I was looking for.

18-Wheeler
12th Aug 2011, 14:42
I've done one in a 747-200F a few years back.
Much as described above, though I can't remember the details accurately. #4 engine was out (Damaged fan blades) and it took both of us to work all the controls for takeoff.
Note that we were extra careful during this takeoff as it was during the Dubai airshow and we knew there'd be hundreds of people there with video cameras - if that's not a recipe for disaster ..... !
FWIW the plane climbed away just fine and went straight to the high 20's for the initial cruise. We got up into the low 30's late in the cruise and were well ahead on the fuel burn as the 3-eng flight plan was very conservative. We cruised at something like M 0.74 or so.
(I think we actually passed an A320 ....)

Swedish Steve
12th Aug 2011, 18:56
I was always curious what would happen if you lost the other good engine
I have travelled on two Tristar ferries. The concensus was that in the 90 secs between take off and V2, you would go down!
Because of this we used to do full boroscopes of the two good engines first.

Procedure was one minute at full power on the good wing engine, then back to idle. Then one minute at take off on Nbr 2, then release the brakes. Feed in the good wing engine at 60 knots, and keep the N1 aligned with the ASI.
There is no V1!, rotate at Vr and pray.


What kind of 4 eng airplane you need to ferry?
BA normally ferries B744 back to LHR for engine change when required. It is cheaper than sending out all the equipement and engine.

galaxy flyer
13th Aug 2011, 03:58
As a bow to 411A, Eastern Airlines did a two-engine ferry in the L-1011, lost one donk during flap retraction and returned. Story was that it happened at Mexico City. I do believe all OEI ferry flights are planned to account for an engine failure, they were in the C-5.

GF

Capt Claret
13th Aug 2011, 04:38
What kind of 4 eng airplane you need to ferry?

I'd guess any 4 engined aeroplane that isn't where the spare engines/engineers are. In my case WABP (Timika) & YBAS (Alice Springs).

And ref. sods law and a second failure, one Sim recurrency session (to allow 3 ENG ferry) saw the second starboard engine fail ex RWY 15 at Cairns. We made the 120 degree left turn to avoid the hills, albeit over water and below the acceleration altitude. :\

I no longer remember the limitations but the procedure as stated by renard is as I recall it.