Engines for ETOPS

[chornedsnorkack]

Which planes can apply for ETOPS?

Twinjets can apply for ETOPS over 60 minutes, from 75 to 207 minutes - and if the airframe, engine and airline qualify, they can get it.

Are nonjets permitted to apply for ETOPS? Say, a twin turboprop - if the engine, airframe and airline meet the necessary qualifications, are they allowed to fly under ETOPS?

And what about other engine types? Like piston of wankel twins - can they apply for ETOPS?

And what about trimotors? Trijets can fly arbitrarily long routes without any extra ETOPS limits, but propeller aircraft need 4 engines for long-haul without extra qualifications. Can trimotors apply for ETOPS?

Are geared turbofans classed as jets or as turboprops? What about propfans?

[Old Smokey]

That's 9 questions in one post chornedsnorkack.

Which one would you like answered first?

The answer to most of the 9 questions is - YES:ok:

Regards,

Old Smokey

[Re-entry]

4 engines 4 long haul. ETOPS= Engines Turn Or People Swim.

[nnc0]

It's going back a ways but I recall the DHC dash 8 (PW 120's turboprops) had an ETOPS AFM supplement for some south pacific/ aus/nz operators.

I doubt a piston engine would ever be ETOPS qualified.

[chornedsnorkack]

It's going back a ways but I recall the DHC dash 8 (PW 120's turboprops) had an ETOPS AFM supplement for some south pacific/ aus/nz operators.
I doubt a piston engine would ever be ETOPS qualified.
What about wankel engines?

And how many piston engines are needed for long haul? Is 4+ needed (B-36 has 6, Hughes Hercules has 8, Saunders-Roe Princess has 10 and Dornier X has 12), or is 3 enough?

[Wizofoz]

Errrr.... And exactley which aircraft has flown equipped with Wankel engines???

As to the pistons you've quoted, none of them had more than four engines because of redundency. They had that many because they needed that much power from the best avaialble engines at the time.

A three-engined pison would no have any distance restrictions on it, provided it could maintain height on any one, but the engineering difficulties of odd numbers of engines has meant that these have been a rarity (Tri-lader and Drover- both modifications of existing twins,and the 1930's Fokker and Ford tris are the only ones that spring to mind).

[barit1]

Wardair operated 727's YVR-HNL long before ETOPS. However in the early days of DC-10 & L1011 marketing, there was some reluctance to employ trijets for transoceanic routes -- some airlines thought their customers might not accept the idea.

There was never a regulatory problem, was there?

BTW - ETOPS applies only to twins - not to 3/4/5/6/8/10 engines!

[chornedsnorkack]

BTW - ETOPS applies only to twins - not to 3/4/5/6/8/10 engines!
How to read, e. g. FAR 121.161 a) then?

[Wizofoz]

I do see your point.

"Unless authorised by the administrator"= ETOPS, which have been developed especially for twin engined, turbine powered aircraft.

If you want to fly a piston twin more than one hour from an airport the answer is usually no except for special authorisations such as ferry flights.

If you want to get authorisation for your three engined Piston or twin wankel aircraft, put together a case showing that the particular airframe/engine/operator combination provides equivelent safety. Difficult because very few of the former and none of the latter exist.

[chornedsnorkack]

I do see your point.
"Unless authorised by the administrator"= ETOPS, which have been developed especially for twin engined, turbine powered aircraft.
If you want to fly a piston twin more than one hour from an airport the answer is usually no except for special authorisations such as ferry flights.

How does the reliability of a piston engine newly designed in 2006 compare with the reliability of a piston engine designed in 1956? What about comparing a piston engine of 2006 with a turbine engine of 1966 or 1986?

Is there any literal regulatory rule that even if a piston engine were to demonstrate IFSD statistic matching the ETOPS thresholds, it would be ineligible to ETOPS just because it is a piston engine?

[Wizofoz]

What about comparing a piston engine of 2006 with a turbine engine of 1966 or 1986?


I would dare say still pretty lousy (plus the fact that most piston engines still in production are varients of 1930s designs!!!). However, etops weren't granted to turbine engines designed in 1966.

As I said, ETOPs is basically an exemption from the rues under a particular set of guidelines. I suppose it is concievable that a theoretical piston could demonstrate the required reliability, in which case you could request that it be included or a new set of guidelines be set up. I doubt that any such engine exisits, however, and would be interested to know what operation you propose would need an ETOPs piston rather than a turbine?

[barit1]

Compare the number of ditchings of turbine-powered aircraft to piston-powered ditchings. :eek:

[chornedsnorkack]

I would dare say still pretty lousy (plus the fact that most piston engines still in production are varients of 1930s designs!!!). However, etops weren't granted to turbine engines designed in 1966.
However, the concession of unlimited diversion time to trijets like B727 does date back to 1960-s. The wording of the rule sounds like turboprop trimotors also automatically have unlimited diversion time.


As I said, ETOPs is basically an exemption from the rues under a particular set of guidelines. I suppose it is concievable that a theoretical piston could demonstrate the required reliability, in which case you could request that it be included or a new set of guidelines be set up. I doubt that any such engine exisits, however, and would be interested to know what operation you propose would need an ETOPs piston rather than a turbine?
Then what are the disadvantages of turbines?

Why are there still piston-engined propeller planes - why aren´t they all turboprops? And on land, while Mazda keeps producing Wankel cars, gas turbine cars do not appear popular.