Jet liner with different engines?

Question

These days, when an airline buys a new plane such as the Jumbo, it has the choice to select jet engines from different manufacturers, such as Rolls Royce, Pratt and Whitney or General Electric.

Can the airline choose to select different engines for its jet liner? For example, can the airline choose one engine from Pratt and Whitney, one from Rolls Royce and one from General Electric for the Jumbo it has bought? The Jumbo will have different engines after its assembly.

Answer 1

no, this is not allowed. different engines have different thrust levels, and fuel consumption. having more thrust on one side of the aircraft would be a bad idea.

Answer 2

Never.  The manufacturers may offer to build a new airliner giving the airline the choice of engines.  Usually no more than two choices. Never would their be different engines on a single plane nor would they be likely to order more than one type of engine for the planes of it's fleet. There are advantages to using only one engine when it comes to ordering spare parts and doing maintenance.

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The 757 when first offered could only have Rolls Royce engines as did the L1011 Tri-star. In the case of the L-1011 it led to it's downfall and failure to make a profit for Lockheed.  

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The 777-200 for example, can have Rolls Royce or Pratt and Whitney engines but never are they mixed on the same plane.  It's an advantage for an airline to use planes which use the same engines because unlike the aircraft itself the engines are changed during it's lifetime.  Being able to order engines in bulk so to speak makes the deal economically sound while on occasion the engine type will be chosen only for political reasons.  When a plane is ordered it's up to the airline to negotiate for the best deal from engine suppliers.

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For decades airlines in the UK specified RR engines out of national pride since they are manufactured there.  G.E. broke that tradition and shocked the world when they sold British Airways the GE90 turbofan for it's 777s over the Rolls Royce engine.

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Answer 3

Technically you could do just about any thing you want. Our executive 727 has a Valsan conversion. The two outboard engines were removed and replaced with higher efficiency and quieter JT8D 219 Pratts. The center engine is original with the thrust reverser removed and a hush kit installed. The aircraft now meets ICAO stager III noise standards and is much more efficient. Especially with the added winglets. So yes, you can get just about anything certified but there has to be a reason.

Answer 4

It would be an expensive and pointless exercise.

Different engines require different control circuitry and in some cases, completely different mountings. There would be no advantage to be gained by mixing engines from different suppliers on the same aircraft.

Fiscal savings in maintenance are gained by standardising equipment, not by radicalising.

Four different engines on the same aircraft require four times as many spares, four times as many maintenance publications and Engineers that are type rated on all four different engines.

Answer 5

Err... No and no.

Answer 6

There are many good points and bad points but i will tell you 1 good point and hopefully you get it from there:

If I have 4 747 in my fleet, 4 engines X 4 planes will have 16 engines on use. Given you have a minimum spare of 2 engines on stock. That is, all engines are GE. the available spare in your fingertips could well supply your needs say engine driven pumps for your hydraulic, oil pressure transmitter could well be cannibalized from your spare engine if you have zero in your stock. BUT if your fleet of 4 747 has different engines then you might be needing a lot of spares whereas if the same fleet of engines, parts are most likely interchangeable and spare problems wouldn't be another cause of your headache. Sometimes just getting spare parts could take you say 3 days and 3 days AOG (aircraft on ground) one loses thousand dollars revenue.