The two engine long haul ops will continue to replace 4-engine types on many routes. This is clearly evident from developments so far.

4 engines, for all but a very few ops...are dead as a doornail.

Except...possibly freight, and even then, as two engine freighters become cost effective in the future, freighters will become twins.

Just the way it is...like it or not.
The only exception is the MD11, but not all that many of those are available.

4 engines, for all but a very few ops...are dead as a doornail
 

Not while I've got a Pound (or Euro) or two in my pocket. Give me four engines every time. The only reason I travel with 4 is there is none around (going where I go) with 6.

Long live the 747 and 340 and 380.


STL

Oceanic Long Haul - 2 or 4?
 

Done lots of trans-atlantic on Stratocruisers, B763s, 2s, 742s, 744s, 340s, 330s.
Done trans-pacific on DC8-43s. 63s, B707s, 747s.
Slightly concerned about B738s west coast NA to Fiji, especially midway between Hawaii and Nandi. Anyway, nevermind.

What are your thoughts on 2 or 4 engines and the comfort level over the vast stretches of the Pacific?

Amelia, you there?

Have operated transPacific with three and four engine jets, and the DC6B and 1649A.

Early types had 4 engines because they needed 'em, such was the reliability...and power requirements.

Don't see how the 4 engine types will survive such is the economics/reliability of twins.

Take the route SFO-HNL for example.
No off-route diversion airfields available...and yet the only type to get a wet footprint on that route was a Stratocruiser (lost two)...a very long time ago.
All survived as it ditched alongside OS November.

2 or 4
 

RT,

The answer to this question might simply relate to the comfort level in the cockpit when you are OEI.

Now, speaking strictly for myself, if I have one shut down I sure feel a deal more comfortable knowing there's 3 out there still churning away.

Give me 4 any day.


STL

I fly with 4 now, but I'd happily take a well-maintained twin over a badly-kept-up 4... though fortunately that's not a problem at our outfit.

It IS nice to be able to keep going to destination should one out of 4 decide to quit, though.

TT

It aint the engines or lack of em that are gonna put you in the drink.

Its fire, or fuel, and fire controll on ETOPS is required to be better than on the quad jets (though many of them have been brought up to similar standards, but not all of em). cargo fire protection is required on etops twins.

Cheers
Wino

Four engines for longhaul, never a truer word said.

Why, with the reliability of modern turbofan engines & ETOPS operations, should "4 engines 4 longhaul" (like the Virgin fallacy displayed on its hulls) be any better?

Before replying emotively I think we should look at the statistics. Have any modern longhaul twin-engine airliners had a double-engine failure? I don't mean those due to fuel starvation, this is just as likely to happen to a four-or-more engined machine.

If anyone can quote some figures that would be great!

I thought the Bearded One was looking into acquiring the Triple as well.... :E

True, unless you lose too many of them... If you start with 4, you can afford to lose 1, and can keep it flying with 2. If you start with less, you can afford to lose less...

However, 4 engines also bring 4 generators, 4 separate full-time hydraulic systems, 4 sources of bleed air for pressurization... Loss of any one of those is usually not a big deal, and loss of 2 is controllable. Again, start with less, and you can afford to lose less...

BlueDog

good at theory of probabilities ?

If one aircraft has two engine failures within three days (not the
same engine), how many more flights will you probably have until
one aircraft has two engine failures within 207 minutes ?
(BTW how many flights exceeded their ETOPS limits until today ?)

It is absolutely scandalous to calculate the life of a passenger
against the operational cost difference between a two and a
four engine airplane.
I cannot believe that so many of my professional colleages
accept the decisions of their bean counting management.
Would it be me alone, no worries, I d fly on a single engine
biplane across the globe but dont we have a responsibility
for our passengers to make their journey as safe as possible ?
Sooner or hopefully later we will have the answer.

As I have just written my thesis on the future of long range operations...Wino has it right IMO, the principle issues are not related to engine reliability. Double engine failure from independent causes is highly unlikely, whereas common cause failures are a) more frequent and b) just as likely to occur aboard a twin as a 3 or 4 engine a/c.

What I find concerning is the push by manufacturers for diversion times " to the limit of the aircraft's most time limited system" LROPS, as proposed by Airbus, might allow for direct flight over Antarctica from South America to South Africa and Australasia. Such flights would involve diversion times up to 8 hours (apparently). Anyone fancy flying 8 hours with a cargo fire?

There are also the usual arguments surrounding "adequate" and "suitable" diversion airfields etc. but the upshot is that the number of engines is less important than it used to be.

HOWEVER..ETOPS and it's succesors (which will probably be called ETOPS btw) should have safety as the primary driver. ETOPS207 in the North Pacific is (IMHO) the first time ETOPS was extended primarily for economic rather than safety reasons. This sadly has given ammunition to those who claim that the FAA sometimes acts as marketing department for U.S industry. This is a shame as the conclusions of the ARAC ETOPS working group are generally quite sound.

topoftheloop,

True, but unfortunately it happens every day. The likes of the NTSB in the states calculate if the cost of a new safety device is worth fitting or not, in terms of how many passenger lives it will save versus the cost of implementation.

This, has, unfortunately been going on for years....

2 vs.4
 

(Airshow conversation with retired United Capt. regarding ETOP's)

Rumer has it that a United 777 had to shut one down last summer over the Pacific.

Apparently cruised beyond ETOP forcing FAA to re-address the time and distance on 1. Can't confirm never heard anything to come of it.

On a related subject. A close friends son works for either P&W or GE running around the world repairing fan blades on BIG THRUST ENGINES. I've been told that the failure rate on the blades have been higher than the past due to their enormous size.

I understand the blades are pitting and wearing at abnormal rates.

I would prefer 4 any day, at least over the Pacific, but as we all know, the airlines would rather save a few dollars and spend less on fuel.
:ok:

Cost of a life.
 

Every safety related industry now calculates the cost of saving a life.

This should not frighten anyone. Every time you or I get into a car, we are making the decision that we are prepared to accept the risk of a fatal accident (which sadly is all too high). We do the same when we fly.

Unfortunately money is not endless. So in order to properly focus investment, we have to have some reference to what is 'cost-effective'. It sounds gruesome, but we all know that there will never be enough money to make railways, cars, or even aircraft 100% safe. So we need a mechanism to make the best decision possible.

No need to panic...the approach has worked pretty well up to now. And I speak as someone works in an industry which uses the approach.

Well I'm sure all of you have heard the old joke.

Two guys sitting in a airport bar.

First guy, "Hey Bob how come you will only fly on 4 engine airplanes?"

Bob, "Because nobody makes 5 engine airliners."

With that in mind, 3 or more for little ole me.

But I have to agree with a lot of points made by Wino.

:uhoh:

I would just HATE to lose an engine over the ocean and only have one remaining.
I am sure all the statistics in the world wouldn't be able to wipe the sweat off my brow at the time.

Can't remember who it was exactly, but some senior bod at Rolls-Royce was once asked what he thought defined a really safe aircraft.

His reply was something to the effect: "If my co-pilot told me that an engine had failed...and I asked him which engine...and he said 'Number 29 sir'...and then I asked him 'Number 29 on which side?'..."

ETOPS - Engines Turn or People Swim

I've done transpac in a twin a couple of times - every sound is amplified, every gauge is more closely examined.