This question relates to this article at Leeham, essentially this article challenges the concept that twin engined airliners are more efficient than quad engined. However the article fails to show the data and prove the arguments. My question is asked to those who are able to confirm the arguments of the article. I will describe my argumentation and formulate the specific answer at the end.
Essentially, in the industry it is preferred to use twin engines vs quad engines based on the following arguments:
- Twin engines have less maintenance cost (2 vs 4).
- Less aerodynamic interference and weight.
- Less cost (4 enginers are more expensive including systems for the same power)
- However less bypass ratio for twin engines and overdimensioning due to compliance with the take-off certification at engine failure.
Netly, twin engines win against quad engines except in the past for ETOPS certification.
Ok, previous statement is my understanding of the trade-off between twin and quad. The article argues (using always seat mile costs) the following:
- Little efficiency between B777-200ER and A340-300 / A380-800.
- 4 CFMs engines or A380-800 4 engines have less maintenance costs than B777-200ER 2 engines. Fleet of CFM is higher as well.
- Argues that B777-200ER requires more powerfull engines. This argument does not contribute, as finally is an efficiency driver and the important is the first argument.
- Previous comparisons are not valid to previous low bypass engines.
- Article is not introducing airplane cost in the comparison (important for capital costs)
So, my explicit questions are the following:
- Can somebody demonstrate with evidences that the efficiency of B777-300ER is lower or higher than A340-300 or A380-800?
- Can somebody demonstrate with evidences that the maintenance cost of the engines of B777-300ER is lower or higher than A340-300 or A380-800?
- Can somebody support further my arguments or support the article?