3 ms·

General Aviation Pilot here - one thing they also leave out is the relaxation on the rules for overwater flight with 2 engines. Prior to the change, it was hard

General Aviation Pilot here - one thing they also leave out is the relaxation on the rules for overwater flight with 2 engines. Prior to the change, it was harder to fly oceanic routes as you had to fly way north to ensure that your nearest airport in case of engine loss was no more than X distance away. With the changes in reliability for engines, they have relaxed that rule which has made 2 engine flights (notable for US => Europe) more profitable as 2 engines flights consume way less fuel than 4 engines flights

phil21 10y ago
Doesn't ETOPS vastly predate the A380? I don't think it's really that relevant, other than in a general sense. To put this in context, ETOPS is what killed MD11 development in the 1980's. The A380 was proposed well after etops-120 was widely utilized by airlines, and etops-180 was announced in 1988 with airlines taking advantage of it relatively quickly. These were certainly were not new unexpected market conditions the aircraft faced after production.
- dorfsmay 10y ago
  Yes. To note also, ETOPS is specific to airplanes with more powerful APU that somehow can help in the case of an engine loss, so they are more like 2.5 engines.
  - frenchman_in_ny 10y ago
    That's not right - the APU doesn't generate thrust.
    - dorfsmay 10y ago
      From a frenchman in YYC! So, you're right, APU cannot deliver trust, but... I just looked into it, I cannot find a definitive answer (without spending hours reading actual legislation, and I don't want to), I think the situation is that some manufacturer use the APU to provide all electrical power in case of single engine operation as a way to leave 100% of power for trust to the one engine that works in order to meet the ETOPS time/distance requirement. In those cases, there are extra regulations around the APU needing to be able to be started at all altitudes etc... In order words, and again if I got that right, you don't need a special APU to be ETOPS, but you can, and if you do there are more constraints on the APU.
      - mrpippy 10y ago
        During single engine operation the APU will definitely be started, if only to provide power/bleed air in case the remaining engine also stops. I believe all ETOPS planes need to be able to start the APU at maximum certified altitude. Interestingly, until recently the 737 (which was not designed with ETOPS in mind) had to leave the APU running for the whole duration of ETOPS flights. It took a few years of data gathering before the FAA was sufficiently convinced that a cold-soaked 737 APU would start at cruise altitude. They now are, and "APU On-Demand" is now used on 737 ETOPS flights (i.e. Alaska Airlines flying west coast US to Hawaii)

phil21 10y ago

Doesn't ETOPS vastly predate the A380? I don't think it's really that relevant, other than in a general sense. To put this in context, ETOPS is what killed MD11 development in the 1980's. The A380 was proposed well after etops-120 was widely utilized by airlines, and etops-180 was announced in 1988 with airlines taking advantage of it relatively quickly. These were certainly were not new unexpected market conditions the aircraft faced after production.

dorfsmay 10y ago
Yes. To note also, ETOPS is specific to airplanes with more powerful APU that somehow can help in the case of an engine loss, so they are more like 2.5 engines.
- frenchman_in_ny 10y ago
  That's not right - the APU doesn't generate thrust.
  - dorfsmay 10y ago
    From a frenchman in YYC! So, you're right, APU cannot deliver trust, but... I just looked into it, I cannot find a definitive answer (without spending hours reading actual legislation, and I don't want to), I think the situation is that some manufacturer use the APU to provide all electrical power in case of single engine operation as a way to leave 100% of power for trust to the one engine that works in order to meet the ETOPS time/distance requirement. In those cases, there are extra regulations around the APU needing to be able to be started at all altitudes etc... In order words, and again if I got that right, you don't need a special APU to be ETOPS, but you can, and if you do there are more constraints on the APU.
    - mrpippy 10y ago
      During single engine operation the APU will definitely be started, if only to provide power/bleed air in case the remaining engine also stops. I believe all ETOPS planes need to be able to start the APU at maximum certified altitude. Interestingly, until recently the 737 (which was not designed with ETOPS in mind) had to leave the APU running for the whole duration of ETOPS flights. It took a few years of data gathering before the FAA was sufficiently convinced that a cold-soaked 737 APU would start at cruise altitude. They now are, and "APU On-Demand" is now used on 737 ETOPS flights (i.e. Alaska Airlines flying west coast US to Hawaii)