THIS is the FlightGlobal article on the topic.

It says:

I do enjoy how they spin the more direct routings as "good for the environment" rather than "saving money on fuel".

I use to fly hours over water with one engine, I don't much care for it but never had a problem. I like more then 2 engines also but in reality, how many is enough?

It will not be long before there will be no ETOPS restrictions.


It is inevitable.

Surely its 3:30 Etops AKA 210 minutes

ANZ aren't opening up the ill-fated Antarctic sightseeing trip again are they ? :-o

It's sad that many of the posts on here show so little understanding of what EDTO/ETOPS certification involves.

Not strictly true.

ETOPS Maintained a/c need to have similar critical systems checked/serviced by different personel. This includes engine oil servicing, IDG servicing, etc. :ok:

compressor stall said : "It's sad that many of the posts on here show so little understanding of what EDTO/ETOPS certification involves."

My understanding is that it means the aeroplane has sufficient redundancy with such things as generators driven from the hydraulics and hydraulics driven off the lectrics - as well as direct from the engines, systems that allow all the systems (undercart deployment, flaps, elevators, ailerons) to be driven in the event of a single engine failure; plus a proven record of low engine inflight shut down rates and an approved minimum equipment list at dispatch, that the certification authorities believe the risks of flying some specific time (distance at a given speed) from the nearest available airfield are acceptable.

The new acronym is Extended Diversion Time Operations and this is one document that sets out one set of rules http://www.casa.gov.au/wcmswr/_asset...s/ops/82_1.pdf

Why do you think other posters are wide of the mark ?

@blade

Nope. It's 330 minute, not 3 hour and 30 minute.

See THIS Flightglobal article.

Only in Aus.

But there are many routes where 330 min could be useful. NZ to South America, any flights crossing Antarctica, US to South Africa etc.

And NZ where these Aircraft are to operate from. Consider this in the context of EDTO (not ETOP's) and things become clearer. As for those states that dont have EDTO, Im sure they soon will.

'Tis easy to do, fuel savings x 3 = tonnes of CO2 (approx) ...:ok:

The real deciding factor for ETOPS times is not "how long can you fly on 1 engine", as the answer is effectively infinitely; these engines have a phenomonally low IFSD rate.
It is fire suppression (for the holds) that is the limiting factor.

When I first heard that it was No. Eight

Lost an engine on a 747 during climb, dumped and went back. Co-pilot queried this decision as we had enough fuel to continue to destination on 3, it being one of those fuel-tankering sectors - i.e. cheaper to top up ( and carry ) with cheap(er) fuel at that departure point. I pointed out that there was a lot of shark infested ocean between departure and arrival points.

QED

Ah yes, but the chances of its also being built on a Monday morning are only 1 in 7...

That's what I like about discussion boards :E

Cold hard facts

actually the poster's assesment that it's mostly aircraft and not engines as the issue is correct

pointless username
 

The crew will have 5h+ to think about the IFSD rate at max continuous thrust.

Who knows? A few tests by Boeing / Engine manufacturer but not enough hours to be statistically valid.

Just build them all with one engine to start with, imagine the fuel savings and other economies that will deliver. If the rationale is to continue flight on one engine for a time which would cover most transit sectors in the world then why do you need two engines to start with? Most commercial flights take off using reduced thrust settings to start with and then reduce thrust further once in the cruise so that the combined thrust of 2 engines would be roughly equal to one engine operating at higher thrust settings. Redundancy can still be supplied and applied through design for one engine (as it is now for ETOPS). It is nothing new for single engine jet aircraft to operate over large expanses of ocean, it was being done long before ETOPS was ever thought of, with the limiting flight time factor being the engine oil capacity.

Sorry to say, servicing (eng oil, idg, bug) does not require separate maintenance crew. Only so many eng systems require separate maint teams, this can also be negated by testing. ETOPS rules with regards to critical system maintenance have never been totally definitive so room for different interpretations exist. I have worked for 2 operators of 777 etops and they both play it differently, which demonstrates the point.