Hi Captain Lim,
Firstly, let me say thank you very much for this extremely informative and helpful website!
I have read through it many times! I also have to admit that it helped me through my last turbulent flight!
I have some question concerning the engines of aircraft. It appears to me that sometimes the same aircrafts types can have different models of engines. Not only can they use different engine products but also different types of similar models too, for example, Singapore Airlines uses on its Boeing 777-200, Rolls Royce Trent 884 as well as Trent 892 and so, as far as I know, Emirates and a lot of other Airlines too.
Why would they use different engine types on the same model of aircraft?
Does it make a difference to you being a pilot? Would you prefer flying the Boeing 777 with engines that have more thrust?
Different engines (eg. RR, GE, PW) have even in their similar models different thrust ratings? So is there something like a specific engine type that pilots love the most? [not taking into account that pilots and passengers like the engines with the lowest failure rate :-)]
As far as I know the climb rate of a Boeing 777 is better than the climb rate of Airbus 340. Does that make a difference for you as a pilot.
Thank you very much in advance for taking your time and effort in answering my questions!
The Boeing 777 has a few models using different engines based on whether the airplanes are used for long haul or medium haul sector. A long haul airplane, for example, the Boeing 777-200IGW (increased gross weight) is fitted with the RR Trent 892 engines. It produces more thrust (90,300 lbs each) because its take off weight, 286,897 kg or 632,500 lbs require more power for take off. The RR Trent 884 engines are less powerful (86,400 lbs each) and are hence fitted onto the medium haul Boeing 777.
It makes no difference to a pilot whether he flies on a Boeing 777 with engines that have more or lesser thrust. It is only a question of whether you are flying on a long haul or on a medium haul route. On a long haul flight, you may be away from your home base longer than usual. It doesn't means that you will fly faster with more powerful engines. The engines with higher thrust will enable you to carry more fuel and take off at a higher weight but both models will still cruise at the same designed speed of Mach 0.84 (84 % speed of sound)
The Boeing 777's are fitted with three different types of engines, depending on which Airlines you are flying with. If an Airline loves British products, they would go for Rolls Royce whereas those who prefer American goods, go for General Electrics or Pratt & Whitney. So these are policy decisions. I have only flown on Boeing 777 fitted with RR engines and I am quite happy with them. Since I have not flown on those fitted with GE or PW engines, I cannot make a comparison except to say that they are all equally reliable.
Comparing climb rates between airplanes can be misleading sometimes because a lighter airplane will always out climb a heavier one irrespective of whether it is a Boeing 777 or Airbus 340. Yes, I believe a Boeing 777 has a better climb rate than a Airbus 340 but it does not make very much difference to a pilot unless there is a race between them :-) Of course, sometimes, it helps if you have a good rate of climb; you would achieve your cruising level earlier but if you are climbing below an Airbus 340, you may be forced to reduce your climb rate in order to provide the safe separation between the two airplanes.