Getting a 787 back in the air after a diversion

Post by mulmen » Sat, Jan 04, 2020, 6:42 AM UTC

sajomojo wrote: post #34

jacquesm wrote: post #26

Earlier quoted context omitted.

Contrary to your assertion the two engined craft are just as safe (or safer!) as the four engined craft because of changes in procedures. Fuel management, weather forecasting, general engine reliability, lubricant reserves are all different and much more stringent for a twin engined jet over water on a straightline route. The effect is the aircraft is less long in the air anyway which has a big effect on the risk cal…

Doesn't the fact that the twin-engine planes have to submit to more stringent ETOPS requirements mean the FAA believes they're less reliable than four engine planes?

Post by WalterBright » Sat, Jan 04, 2020, 6:47 AM UTC

sajomojo wrote: post #31

WalterBright wrote: post #24

Earlier quoted context omitted.

> If the FAA wanted to prioritize safety, it would still require the use of four-engined planes, as it used to for most long ocean routes. The desire to fly twin-engine planes over the ocean is entirely driven by a desire to maximize airline profits. That intuitively makes sense, but it's incorrect. The FAA certified twin engines over water because it's safer. Half the number of engines mean half the failures, and ha…

Can you point to the statistics? I'm sure modern twin-engine planes are more reliable than very old four engine planes but what about modern vs modern?

Post by WalterBright » Sat, Jan 04, 2020, 6:47 AM UTC

jacquesm wrote: post #27

WalterBright wrote: post #23

Earlier quoted context omitted.

I might add that lighting a fire under a gas engine that likely has leaks and drips is a pretty ballsy thing to do.

Usually done for big rigs, diesels not gas engines.

Post by jrockway » Sat, Jan 04, 2020, 6:49 AM UTC

sajomojo wrote: post #42

jrockway wrote: post #38

Earlier quoted context omitted.

ETOPS seems to have done pretty well. As far as I know, no ETOPS-certified twinjets have been lost due to both engines failing. There are a couple cases of the jet running out of fuel (the famous Gimli glider and Air Transat Flight 236), but that is going to be bad no matter how many engines you have. There are cases of airplanes flying into volcanic ash clouds and losing all engines; but more engines doesn't help yo…

Thanks for the thoughtful replies, all. I still don't buy the idea that this change was made with public safety as the top priority. I do get that it might be a reasonable trade off of safety/profits. I really do hope the ETOPS rule changes turn out to be a good choice over the long term.

Post by CaliforniaKarl » Sat, Jan 04, 2020, 6:51 AM UTC

sajomojo wrote: post #31

WalterBright wrote: post #24

Earlier quoted context omitted.

> If the FAA wanted to prioritize safety, it would still require the use of four-engined planes, as it used to for most long ocean routes. The desire to fly twin-engine planes over the ocean is entirely driven by a desire to maximize airline profits. That intuitively makes sense, but it's incorrect. The FAA certified twin engines over water because it's safer. Half the number of engines mean half the failures, and ha…

Can you point to the statistics? I'm sure modern twin-engine planes are more reliable than very old four engine planes but what about modern vs modern?