FAA NEW RULE 180 minute for multiple engines
 

Has the FAA introduced a new rule for multiengine aircraft so they can't go further than 180 minutes from an alternate airport.

Knew it was coming, ETOPS will affect all aircraft despite the twin in the abbreviation.

On the face of it, that seems utterly ridiculous.

What is the rationale for this decision? Who does it affect: all traffic originating from US airspace or any aircraft operating anywhere where the airline is US based?

The OP asked a question rather than making a comment. He just forgot the question mark.

Knew it was coming, ETOPS will affect all aircraft despite the twin in the abbreviation

One needs to look at the history.

Pre-ETOPS, the design/operating standards required that multi-engine aircraft be able to meet certain performance standards with two failed engines else they were restricted by the 90 minute rule.

Clearly this affected all twins but, also, restricted some 3/4 engined machines.

As the reliability of engines improved, we saw the introduction of (progressively longer) ETOPS operations by the larger twins.

As engine and systems reliability has improved over the years, the concern, for some years, has been less with the (number of) engines and more with other systems considerations - ergo, the number of engines is now largely irrelevant, with the concern being more along the lines of "if we are a LONG, LONG way from a safe haven, how are we placed if this, that, or the other circumstance might occur ?"

It might be better to replace ETOPS with something like "operations remote from suitable aerodromes" and move away from a concern specifically directed towards the number of engines.

JT,

I think a lot of this has to do with diversion planning as related to route planning. It places more onus on the planners to assure airports which can accept large 3 or 4 engine airliners are along the route and within the 180 minute limit.

j.t.:

John,

Pre-ETOPS, twins couldn't make "crossings."

As I recall with 3 or 4 engine birds, we had to turn around under circumstances.

Ahh, 180min with extension is not a big deal. 3 and 4 engine aircraft will not be as restricted having more redundant systems anyways. To the question above, as far as I know being in the US it will apply to FAA reg acft, expect the world to follow or be onboard. 180 ETOPS is more a burdon on MX... But there will be less rules as negociated with the CAA as there are redundant systems a twin can not provide.

TD & A,

Indeed, the extant operational problems are the day to day drivers. However, the two-engine out cruise capability driver in concert with the restrictive 90 minute rule started the gameplay originally.

Yeah, J.T. , hope you would agree that the 180 minute rule will not harm most segments, hell for those that they do they will only build more airstrips... Correction, lengthen runways, creating more jobs.


Edit.. Back to the days that Pan Am built airports. "If you build it they will come" may be a good thing, pioneering once again!

Utterly ridiculous, the FAA has no knowledge or concern for 3 and 4 engine operations. They are trying to fit everything into their narrow 2-engine view. While ETOPS experience has made ALL airliners, regardless of engines, more reliable and safer, there is no reason to restrict 3 and 4 engine airliners to having 180 minute ERAs. A 747 OEI has more redundancy than a B777 takes off with.

Engines are not redundant when you run into ice crystals, dirty fuel, ash, or quik chk maint. that forgets to put the caps back on the oil tanks or borescope or even when an engine blows up on one side and sheds its parts into its neighbor.

Yes, lomapaseo

But, if any of those events happen, it doesn't matter how many engines the plane has. A four-engine plane is a very different beast the the twins and twin operations rules should NOT be applied to them. The FAA is showing its lack of knowledge and experience in restricting quads. But, then again, they might just be in the pocket of Mr. Boeing and Company.

GF

"A very different beast" :confused:

Yes, 2 vs 4 .

Yes, both certified to fly with a single engine out. Both in need of a diversion with two engines out. And the one with more engines has a greater chance of independent failure combinations, not to mention the myriad of risks having nothing to do with muliple engines out.

I never thought of this as a Boeing or Airbus design issue because it hurts my brain to figure out why it is good or bad.

I deal with historical data and safety analysis.

But in the greater sphere of things it's small change in contribution to overall risk, so I only get into this fray for fun :)

Lamapaseo:

Quote:

---

Yes, 2 vs 4 .

---

No, the twin doesn't because it's going into the drink.

The four engine aircraft has a greater chance of an engine failure and thus a turn around fairly early in the flight. But, that chance is very small. Once you get far out the 4 engine aircraft is simply safer than the two engine aircraft, but the economics are not as good. So, ETOPS is all about money.

The greater chance of an engine failure "early on" in a 4-engine bird is an "insurance payment" for greater safety when out somewhere in the middle, more or less.

Assuming the engines to be perfectly reliable (100% reliability no matter the conditions), what is left on the aircraft that is now more of a factor in terms of adversely affecting safety?

Put another way, of ALL diverts of aircraft flying hours away from the nearest suitable, how many were due to something NOT engine related?

Any figures?

EDIT to add:

Agreed that more engines increases the risk of an engine failure, but what is the chance of a 4 engine suffering dual-engine failure compared with a twin suffering dual-engine failure?

Assuming the engines to be perfectly reliable (100% reliability no matter the conditions),

With such an assumption then we can presume that folks will fly in single engined airliners - why waste all that money on more than one really needs ?

Put another way, of ALL diverts of aircraft flying hours away from the nearest suitable, how many were due to something NOT engine related?

Don't have any figures to hand. However, systems other than engines are the driving concern in recent years - multiple electrical failures, on board fire are but two which spring to mind.

what is the chance of a 4 engine suffering dual-engine failure compared with a twin suffering dual-engine failure?

Somewhat higher, I suggest - two engines are on the same side. If one lets go in a big way, there is a rather higher probability that debris will take out the adjacent engine rather than (the) one on the other side. Plently of examples around to back up that thought.

It was hypothetical. :) In other words, if the engines are removed as a concern, then what is next? You addressed this though in your next part of your reply.

Quote:

---

Put another way, of ALL diverts of aircraft flying hours away from the nearest suitable, how many were due to something NOT engine related?

---

Fire is a strange one; it is thought in a lot of cases they couldn't reach the surface in time even if the airport was ideally located (e.g. Swissair Flight 111).

Quote:

---

what is the chance of a 4 engine suffering dual-engine failure compared with a twin suffering dual-engine failure?

---

That is a good point. Even the Qantas A380 ended up being unable to control #1 after the #2 let go, despite #1 itself being undamaged.

It was hypothetical.

.. as was my tongue-in-cheek response ..

There were three Nimrods, one made it, one ditched and one didn't.

OK not a modern design and based on the Comet but in each case the time from fire to catastrophe was extremely short. Of the one that landed and the one that ditched, neither was at a normal transit altitude when the emergency occurred.