Lets use the B757 as an example. Engine options are PW2000 and the RB211. As I'm sure they are both FADEC engines we don't have to worry about and mechanical linkages and such. But each engine although comparable in thrust ranges have different requirements from the aircraft.

As a B757 pilot are the procedures different between the airframes with different engine options?

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    $\begingroup$ Are you asking only about FADEC controlled engines on large aircraft? For example, the B206 helicopter has 2 different starting systems, the CECO and the Bendix. Getting a CECO engine start wrong can cook the engine before you do anything about it. Bendix starts are a lot more forgiving. $\endgroup$ – Simon Jan 25 '17 at 20:58
  • $\begingroup$ No, I'm asking if airframes with different engine options have different procedures for handling. FADEC or not. The example I used happens to have engines with FADEC. $\endgroup$ – LuftBier Jan 25 '17 at 21:19
  • $\begingroup$ As a general rule, you may want to wait a while before accepting an answer. Questions with accepted answers often don't get additional answers, and that may limit the amount of information you receive. I'm not implying in any way that Stefan's answer is wrong, just that someone with additional information may skip over this question because they see it has an accepted answer already. $\endgroup$ – FreeMan Jan 26 '17 at 19:11

I can only speak for the Boeing B787, but the 787 Flight Crew Operating Manual (FCOM) indicates that there are slight differences between different engine options. Three examples:

  • autostart modes (different failures can be automatically detected and corrected for during engine autostart),
  • warm-up times before take-off and cool-down times after landing,
  • take-off thrust setting ("GE engines: Advance the thrust levers to approximately 40% N1" vs "RR engines: Advance the thrust levers to approximately 20 TPR" - this also indicates that the primary engine indications are slightly different: N1 and EGT vs. TPR, N1 and EGT).

I don't know though how much these slight differences translate to different procedures, as I am not a pilot.

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  • $\begingroup$ Thank you. I imagine that technology has helped as many of the functions a pilots used to have to accomplish have become automatic. My question originally stemmed from the thought that with older airframe engine combinations would this even be possible. By older I mean engines that would have had mechanical linkages between the throttle and engine. Since most engines are designed with the accessories in different locations I don't think they would be able to be interchangeable. But as I think back, offering different engine options is a relatively new idea probably dating back to the 80s. $\endgroup$ – LuftBier Jan 26 '17 at 11:02
  • $\begingroup$ This seems to be common difference—RR, and IAE, engines show EPR and use it as primary reference while most others have just N1. It is so on Airbus aircraft too. $\endgroup$ – Jan Hudec Jan 28 '17 at 22:35
  • $\begingroup$ @LuftBier, when there are multiple engine options, a different nacelle is designed for each. So the interface is in the pylon and the accessory layout does not really matter. Also note that while early jets were not offered with alternate engine options from the start, they were often re-engined later. Especially the military ones (air force still uses many 707-based planes, but all have modern engines). $\endgroup$ – Jan Hudec Jan 28 '17 at 22:40

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