What happened with the 'landing' Korean took much longer than the incident (accident ) with the Turkisch. But... the landing of the A340 was definitely more scary.
Today a turkisch B777 and the particular A340 departed from Rwy25R without any problems. The A340 took off without engine nr1, what I find quite strange. I doubt that many companies would depart with an A340 already missing 1 engine. They are not the most performing a/c... at least for what concerns their climbing capabilities. I thought it didn't even departed from full rwy length (not w4 but rather b1) and it was airborne quite late (b8, b9.. difficult to say)
katarsis wrote:I doubt that many companies would depart with an A340 already missing 1 engine. They are not the most performing a/c...
I don't know the procedures on 4 engined aircraft. 2 engined aircraft are powered to be able to climb out at take-off weight with n-1 (-50% thrust available). I think the same rule applies to 4 engined aircraft, but that rule has different consequences: n-1 for a 4 engined aircraft means they only loose 25% of their available thrust. In other words: 4 engined aircraft are less overpowered than 2 engined aircraft.
The question: is an A340 capable of climbing out at take-off weight with n-2 (worst case would be fully assymetric). I know the A340 was probably light compared to its MTOW, nevertheless i think katarsis has a point when he questions safety as an aircraft takes of with one engine inoperative.
katarsis wrote:I doubt that many companies would depart with an A340 already missing 1 engine. They are not the most performing a/c...
I don't know the procedures on 4 engined aircraft. 2 engined aircraft are powered to be able to climb out at take-off weight with n-1 (-50% thrust available). I think the same rule applies to 4 engined aircraft, but that rule has different consequences: n-1 for a 4 engined aircraft means they only loose 25% of their available thrust. In other words: 4 engined aircraft are less overpowered than 2 engined aircraft.
The question: is an A340 capable of climbing out at take-off weight with n-2 (worst case would be fully assymetric). I know the A340 was probably light compared to its MTOW, nevertheless i think katarsis has a point when he questions safety as an aircraft takes of with one engine inoperative.
The A340 -just like any other quad- is certified for 1 engine out ferry flights, provided certain operating procedures are taken into account by the pilots, like stricter limitations of take-off weight, runway width, cross wind and WX. On top of that performance calculations need to be done to guarantee obstacle clearance in case of a second engine failure on take-off, but there are dedicated graphs for this in the flight manuals.
Really no big deal, you know: it happens regularly and is a nice option quads have as it is much cheaper to simply ferry the plane home where the maintenance base is, than to send an engine overland to the airport where the plane is stuck.
FWIW, SN regularly does it on their RJs too, at least a couple of times per year...
Thanks for the info tolipanebas. So i guess the A340 can maintain balanced flight with 2 engines out on 1 side and climb power on the remaining 2 engines then?
teddybAIR wrote:Thanks for the info tolipanebas. So i guess the A340 can maintain balanced flight with 2 engines out on 1 side and climb power on the remaining 2 engines then?
why wouldn't it?
Think about it, it's just the same situation as a single engine failure on a twin really, isn't it?
Yet, I thought that the fact that the number 1 and 4 engine our farther from the longtitudinal axis, might play a role here.
Example: I wouldn't wan't to be faced with a 1 engine out on a V-22 Osprey
The military aren't certifying their planes under FAA/EASA rules though: who knowns, their solution might be to eject. Haven't come across that in the Airbus FCOM.
The V-22 example was just to illustrate that I assumed that the moment-arm of the operative outboard engine could be a factor in the initial climb-out. But I'm quite confident that all procedures were respected! That is probably the reason why it took so long before it departed from Brussels anyway...
teddybAIR wrote:The V-22 example was just to illustrate that I assumed that the moment-arm of the operative outboard engine could be a factor in the initial climb-out. But I'm quite confident that all procedures were respected! That is probably the reason why it took so long before it departed from Brussels anyway...
and they have not removed the Justice Palace or Atonium out of the way
it is correct that twin engine a/c are more overpowered than 4-engine a/c. With 1 engine out at the critical moment during take off, an a/c must still be able to maintain a positive climb (I suppose even when at MTOW). For a 4 engine a/c however it does indeed mean that still 75% of the total engine power can be used for while there's only 50% left for the twin engine a/c.
I suppose the A340 can only depart safely with 3 engines if it's weight is well below MTOW. In this case I think the airbus had no pax nor any other payload. It would not have been easy to return to the field when his engine nr2 gave up as well ... glad that didn't happen
Gents, of course the ferry flight had to be operated empty.
And I can tell you, an empty A340 with 2 eng-out has still got some performance. (probably not at JNB, but at BRU on a cold day, it surely has)
3-engine ferry flights have been around for decades. If the airline is not too dumb, follows the procedures and makes sure the crew is properly trained it's not a big deal.
TCAS_climb wrote: If you have the time and curiosity to search the internet you will even find pictures of a DC-10 with a fourth engine attached to the wing.
Sorry for going off topic , but are you sure about this ? I have seen photos of a Lockheed Tristar carrying a spare engine under the wing , but I was not aware that the DC-10 had this capability too .
edited to add : Sorry , I should have done a search before doubting you - sure enough here is a link to a photo of an LH DC-10 carrying a spare
Three engines ferry flight is part of the FM, therefore it is allowed for non-revenue flight.
T.O. computation takes into account worst case scenarii:
- With outer engine unserviceable, failure of the other outer engine @T.O. and LDG extended.
- With inner engine unserviceable, failure of the outer engine on the same wing.
When the engine is seized, I don't think 3 Engines ferry flight can be performed, also, derated T.O and flight with gear down are not allowed with one engine inop.
I think three engine ferry flight is an option, and operators have to pay the manufacturers to have access to the specific performance database of such operation.
By the way, the THY captain of that flight has resigned from THY saying he had been very tired and had made some errors during the landing???
THY has immediately released an announcement saying all their pilots do have enough rests and they make sure the pilots don't exceed the allowed flying times at time.
hakan wrote:
THY has immediately released an announcement saying all their pilots do have enough rests and they make sure the pilots don't exceed the allowed flying times at time.
One engine out ferry flights are common practice on quads. The only thing that needs to happen is an authorization made by the OEM and the authorities. However, one engine out ferry flight on a twin have, as far as I know, never happened. Just to clarify, the plane takes off, flies and lands, all on one engine. There is quite a large debate going on about this topic in the Tech/Ops forums of airliners.net, which is actually quite a good read.
) with the Turkisch. But... the landing of the A340 was definitely more scary.
