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AviationHas the wrong engine ever been mounted after maintenance?
[+11] [1] user14481
[2016-04-14 19:11:12]
[ jet-engine engine flight-testing multi-engine ]
[ https://aviation.stackexchange.com/questions/26939/has-the-wrong-engine-ever-been-mounted-after-maintenance ]

Keeping in mind that a plane can fly with different engine models ( e.g. for test purposes [1]), has an error ever happened during normal operations that led to the wrong engine being mounted? Is some kind of calibration or check necessary before flight to ensure that the engines are the correct ones?

(3) Is the included video meant to be an example of a different engine being mounted? It's not as simple as swapping engines, there's a lot more modification that has to be done. - fooot
what kind of modification? I would like to have some info. edited video link to start at 0:57 where it zooms on the engines and you can clearly see they are different. also look at 1:37, really clear also in that point. - user14481
(1) I would say no, its not possible. Maintenance is tracked very carefully by serial number. If they did something like this it would mean the correct serial numbered engine for another aircraft was missing. - Ron Beyer
You are realizing, aren't you, that the whole point of the flight in that video is to test a new engine? - TomMcW
(13) Excluding test engines, most airliners that have different engine options also have different pylons for each engine option (the 787 was intended to have a common pylon for both engine options, but this was quietly dropped as a concept, as was the ability to quickly convert from one option to the other), so you would have to bodge a lot of stuff to hang a different engine off of a pylon meant for something else... - Moo
Is it possible to have an 2 nearly identical engines, one ETOPS rated and the other not? - GdD
(3) You imagine they have got a bunch of engines sitting around in the corner of a hanger? - kevin
Possible... it is. Now is this likely to happen... definitely no. You should rephrase your question asking for what does prevent an inversion to be made from technical and methodological standpoints. - mins
@kevin if you have engines in the corner of a hanger, I want to see your wardrobe! If instead you have an hangar, I would like to have a guided tour. - Federico
@kevin most airlines do. The biggest risk I could see is airlines that have engines that are physically the same but have different name plate thrusts, but I am pretty sure the Avionics on modern airliners check the name plate of the engine through the FADEC. - OSUZorba
(5) The closest thing I can think of is the Air Transat 236 flight that was caused by a different engine being mounted. However, the issue was that they used an incorrect pump, the engine itself was fine. - Pondlife
I saw a documentary on Trumps 757 where after being sent for a repair the wrong engine was sent back. It was on the crane about to be mounted when they checked the serial numbers and saw they didn't match. Same type of engine, but still technically "wrong" - Mennyg
@Mennyg I think it was just the inlet that they thought was wrong. - fooot
[+2] [2017-05-11 09:59:33] TayE

January 2016: a "wrong" or non-functioning engine was mounted onto a Qantas 747. QF63 departed from Sydney to Johannesburg with a 5th engine.

The 747 is capable of carrying these kind of loads through anchor points on each of their wings.

enter image description here

Disclaimer: this wasn't by mistake, it was intended to get the "5th" engine to Johannesburg ASAP, to be fitted onto another aircraft.

As for the possibility of mounting an incorrect engine on an airplane by accident, it's very unlikely (impossible really). Jet engines are designed exclusively with the aircraft in mind. Further, jet engines are expensive you would make certain you order the correct engine for the corresponding aircraft. Aviation mechanics also receive sufficient training and the an engine replacement process isn't a one man job. It circulates through a group of individuals prior to actually making a purchase or deciding to fit a new engine.

Besides, even in the case where some unqualified individuals were to attempt mounting an incorrect engine, it wouldn't work. First, they would easily be able to distinguish the existing engines from the replacement. Second, the mounting the engine in the place wouldn't work, the mount points would be of a different shape and would consist of bolts and screws in different locations.


(1) The 5th pod stuff is irrelevant to the question - Steve Kuo
(2) That's a bit harsh. It's a great answer that covers all the bases and gives us the "closest case". - Fattie
(1) Is there a mount point under each wing, or is there only the 5th one? - T.J.L.
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