United Flight 328 Engine Explodes

[RkFast]

I had an interesting "argument" on twitter (I know, I know) with folks trying to make the point that it was "government regulations" that "forced" Boeing to design the 777 (and all their other two holers) to be able to fly on only one engine.

 

'Twas a good one....

Edited March 1, 2021 by RkFast

[GG1]

49 minutes ago, RkFast said:

I had an interesting "argument" on twitter (I know, I know) with folks trying to make the point that it was "government regulations" that "forced" Boeing to design the 777 (and all their other two holers) to be able to fly on only one engine.

 

'Twas a good one....

 

Hasn't been this a standard practice for all plane manufacturers since they introduced double engines?

[Sherpa]

13 hours ago, GG1 said:

 

Hasn't been this a standard practice for all plane manufacturers since they introduced double engines?

 

The FAA never forced airplane manufacturers to move to two engine airplanes.

The reasons were that engines became so overwhelmingly reliable and thrust increases made it so that more than two isn't necessary.

 

The other main reason is the approval of two engine airplanes on ETOPS (Extended range Twin engine Operation Standards) in the mid 1980's.

 

That approval permits twin engine airliners to operate on long range international, largely over water or areas with minimal divert airport availability.

Once that rule, called the 120 minute rule, was approved, two engine airplanes could fly the North Atlantic Track System between the US and Europe as well as many other routes previously limited to three or more engine aircraft.

Prior to that, two engine airplanes only made sense on shorter routes.

 

The 777 operates under the 180 minute rule, opening up US-Asia routes.

The 777 with GE engines or Rolls Royce Trent engines are so approved.

Not sure about the Pratt and Whitneys. I flew the 777/Rolls Royce Trents.

 

The engine manufacturer must prove through extremely demanding testing that the airplane can lose an engine at cruise altitude, descend to it's single engine cruise altitude capability, and divert to an acceptable alternate airport from that route within that time limit.

In addition, years of testing must verify certain expected mean time between engine failures to even get to ETOPS consideration.

 

Aside from that ETOPS ruling, which really made two engine operations possible, the basic rule for a two engine airplane is that it must be able to accelerate to "decision" speed, (which is  calculated and called out on every takeoff), and the speed below which you abort and above you continue the takeoff.

From that speed, called "V2," with a critical engine failure, the airplane at max gross weight must be able to continue the takeoff roll, get airborne, and once the landing gear is retracted, obtain a 2.4% climb gradient with the remaining engine at max power.

 

Edited March 2, 2021 by Sherpa

[Sherpa]

Small type.

Decisin speed is V1 not V2.