I was reading about the in flight engine shutdown of Qantas Flight 144 between SYD and AKL. https://www.seattletimes.com/business/q ... ng-sydney/

It got me to thinking, what are the real world statistics of in flight engine shutdowns (IFSD) on ETOPS maintained airplanes? It looks like SYD-AKL requires 90 minute ETOPS.

I did a brief bit of browsing, and it appears that IFSD need to be reported, but I wasn't able to find the statistics at the FAA website.

How frequent are IFSDs in actual operation? (as opposed to for training purposes, which the regulation specifically excludes.)

Boeing used to issue a quarterly report that was very informative. It was somewhat hard to get ahold of, I got aceess at the airline I worked at, I don't think the general public had access. I think that perhaps one reason the information was restricted is that it exposed certain engine manufacturers. For example, on the 767-300ER, the historical IFSD rate of the CF6-80C2 was about half that of the PW4000. I can't imagine that PW liked seeing that out there.

Airbus eventually started publishing similar information. It was formatted somewhat differently and once again circulation was somewhat restricted.

IFSDs are relatively rare. For many years, diversions due to passenger concerns (passenger medical emergencies, a water or lavatory system failure, etc.) have been more common.

ETOPS isn't even a "thing" any more. The procedures are all "baked in" as standard operating procedures. ALPA and Airbus were wrong. Twin engine long range flying is wildly successful and has had many benefits. Some of the benefits are millions of gallons of fuel savings and more international flights at smaller cities.

PS I expect some may argue about my statement about Airbus and ALPA being wrong. ALPA was very tepid about support of ETOPS. Sorry no link, it's just a memory. And although Airbus built the first widebody twin they also were very unenthusiastic about ETOPS. Will they ever live down "4 engines 4 the long haul?" Boeing led the way (many here may recall that I've been very critical of the current Boeing, so I'm not biased) on ETOPS. I find it quite interesting that now that ETOPS has proven successful, the Europeans had to come up with their own acronyms, and claim their A300 props even though the early A300 couldn't fly far enough to even need ETOPS.

So I guess to summarize: the data is out there but may not be readily available to laymen because perceptions are actively and aggressively managed.

SteelChair wrote:

Boeing used to issue a quarterly report that was very informative. It was somewhat hard to get ahold of, I got aceess at the airline I worked at, I don't think the general public had access. I think that perhaps one reason the information was restricted is that it exposed certain engine manufacturers. For example, on the 767-300ER, the historical IFSD rate of the CF6-80C2 was about half that of the PW4000. I can't imagine that PW liked seeing that out there.

Airbus eventually started publishing similar information. It was formatted somewhat differently and once again circulation was somewhat restricted.

IFSDs are relatively rare. For many years, diversions due to passenger concerns (passenger medical emergencies, a water or lavatory system failure, etc.) have been more common.

ETOPS isn't even a "thing" any more. The procedures are all "baked in" as standard operating procedures. ALPA and Airbus were wrong. Twin engine long range flying is wildly successful and has had many benefits. Some of the benefits are millions of gallons of fuel savings and more international flights at smaller cities.

PS I expect some may argue about my statement about Airbus and ALPA being wrong. ALPA was very tepid about support of ETOPS. Sorry no link, it's just a memory. And although Airbus built the first widebody twin they also were very unenthusiastic about ETOPS. Will they ever live down "4 engines 4 the long haul?" Boeing led the way (many here may recall that I've been very critical of the current Boeing, so I'm not biased) on ETOPS. I find it quite interesting that now that ETOPS has proven successful, the Europeans had to come up with their own acronyms, and claim their A300 props even though the early A300 couldn't fly far enough to even need ETOPS.

So I guess to summarize: the data is out there but may not be readily available to laymen because perceptions are actively and aggressively managed.

Well said. The A300 may have been the first widebody twin, but the 767-200 and 200ER arguably ushered in the era of longhaul ETOPS

AFAIK, "4 Engines 4 Long Haul" was more or a Virgin Atlantic marketing gimmick than something Airbus pushed really strongly.

That being said, it did sense from a marketing perspective for Airbus. Boeing had the 777, but Airbus had the A330/A340, with the long-haul version being a quad. If they'd only had a twin like Boeing, marketing would no doubt have looked different.

Of course, that sort of gimmick has little effect when actually selling the aircraft to an operator. Airlines want actual data, not catchy slogans.

Starlionblue wrote:

AFAIK, "4 Engines 4 Long Haul" was more or a Virgin Atlantic marketing gimmick than something Airbus pushed really strongly.

.

From my memory it was Airbus that came up with that, VS ran with it.

«How Boeing defied the Airbus challenge» by Mohan Pandey tells the story about ETOPS extensions, the A340 and the 777.

Interesting how what was initially pushed as almost impossible safety-demands on twins initiated by Airbus and the pilot unions, eventually turned into an such an incredible success-story in safety that they in the end were imposed on quads as much as twins!


It’s a long time since the T in ETOPS meant «twin»

M564038 wrote:

«How Boeing defied the Airbus challenge» by Mohan Pandey tells the story about ETOPS extensions, the A340 and the 777.

Interesting how what was initially pushed as almost impossible safety-demands on twins initiated by Airbus and the pilot unions, eventually turned into an such an incredible success-story in safety that they in the end were imposed on quads as much as twins!


It’s a long time since the T in ETOPS meant «twin»

ETOPS was a success due to demands of Airbus and the pilot unions? That is some real revisionist history there, it takes quite a lens to see the situation that way. Sadly, Tony Broderick has passed so we can't interview him.

And yes, the FAA finally changed the T. There were many inconsistencies, for example 747 had grossly inadequate cargo compartment fire suppression for the distances it flew from airports, but was "safe" because it had 4 engines.

SteelChair wrote:

M564038 wrote:

«How Boeing defied the Airbus challenge» by Mohan Pandey tells the story about ETOPS extensions, the A340 and the 777.

Interesting how what was initially pushed as almost impossible safety-demands on twins initiated by Airbus and the pilot unions, eventually turned into an such an incredible success-story in safety that they in the end were imposed on quads as much as twins!


It’s a long time since the T in ETOPS meant «twin»

ETOPS was a success due to demands of Airbus and the pilot unions? That is some real revisionist history there, it takes quite a lens to see the situation that way. Sadly, Tony Broderick has passed so we can't interview him.

And yes, the FAA finally changed the T. There were many inconsistencies, for example 747 had grossly inadequate cargo compartment fire suppression for the distances it flew from airports, but was "safe" because it had 4 engines.

I think you read me wrong.
Airbus tried to counter the threat from the 777 by getting the regulators and unions onboard with some pretty (for the time) outlandish demands on 2 engine aircraft for long-haul.
It backfired as Boeing(and in turn airbus) complied, and very successfully made the sky a safer place, as you mention one example of yourself.

SteelChair wrote:

ETOPS was a success due to demands of Airbus and the pilot unions? That is some real revisionist history there, it takes quite a lens to see the situation that way. Sadly, Tony Broderick has passed so we can't interview him.

Airbus had the A300 flying trans Atlantic beyond 60 minutes before ETOPS regulations came into effect.

USAirKid wrote:

It got me to thinking, what are the real world statistics of in flight engine shutdowns (IFSD) on ETOPS maintained airplanes? It looks like SYD-AKL requires 90 minute ETOPS.

The stats these days are rather meaningless, with all the engine monitoring that is done engines are pulled before they fail.

zeke wrote:

USAirKid wrote:

It got me to thinking, what are the real world statistics of in flight engine shutdowns (IFSD) on ETOPS maintained airplanes? It looks like SYD-AKL requires 90 minute ETOPS.

The stats these days are rather meaningless, with all the engine monitoring that is done engines are pulled before they fail.

Engine reliability goalposts are there is to ensure than the plane can make it to a runway in pretty much any scenario (1e-9 crash probability).
From that point of view, it doesn't really matter if that reliability metric is achieved by using thicker metal with 10x safety margin, or by constant monitoring. The first approach costs fuel, and the second costs maintenance budget. What you say is second approach becomes dominant. As a passenger who prefers getting to the destination in one piece (and hence from the regulator standpoint) that's fine as long as it works. So shutdown statistics in that monitoring scenario may not tell airline cost story, but it definitely tells the expected crash rate story (a pretty optimistic one!)

Not all engines are pulled before they fail. Engines still occasionally fail randomly. It's pretty rate, but imho it is good that the failure rate is monitored.

One should also not forget that after the first years of ETOPS, subsequent engines were designed with ETOPS in mind and therefore have even better reliability.

kalvado wrote:

What you say is second approach becomes dominant. As a passenger who prefers getting to the destination in one piece (and hence from the regulator standpoint) that's fine as long as it works. So shutdown statistics in that monitoring scenario may not tell airline cost story, but it definitely tells the expected crash rate story (a pretty optimistic one!)

So you have two aircraft side by side, one set of engine been on with 100,000 hrs each, no damage, no failure. And another aircraft that has had its engines replaced at 20,000 hrs, it’s on its 5th set of engines. No engine failure with each engine.

They both have the same reliability on paper.

zeke wrote:

kalvado wrote:

What you say is second approach becomes dominant. As a passenger who prefers getting to the destination in one piece (and hence from the regulator standpoint) that's fine as long as it works. So shutdown statistics in that monitoring scenario may not tell airline cost story, but it definitely tells the expected crash rate story (a pretty optimistic one!)

So you have two aircraft side by side, one set of engine been on with 100,000 hrs each, no damage, no failure. And another aircraft that has had its engines replaced at 20,000 hrs, it’s on its 5th set of engines. No engine failure with each engine.

They both have the same reliability on paper.

Both have expected probability of a dual engine failure. As a passenger, that's all what matters for me.
As for airline... They have more parameters to care about. It's more about cost, where time on wing is only one of multiple parameters. Acquisition cost, weight, efficiency, dispatch rate... And that is before bathtub curve is even mentioned!
What I hear so far is predictive maintenance is still cheaper...

zeke wrote:

kalvado wrote:

What you say is second approach becomes dominant. As a passenger who prefers getting to the destination in one piece (and hence from the regulator standpoint) that's fine as long as it works. So shutdown statistics in that monitoring scenario may not tell airline cost story, but it definitely tells the expected crash rate story (a pretty optimistic one!)

So you have two aircraft side by side, one set of engine been on with 100,000 hrs each, no damage, no failure. And another aircraft that has had its engines replaced at 20,000 hrs, it’s on its 5th set of engines. No engine failure with each engine.

They both have the same reliability on paper.

Which is fine. I'm interested in unexpected inflight shutdowns for ETOP equipped and maintained airplanes. How an airline gets there is upto its management and its regulators.

zeke wrote:

SteelChair wrote:

ETOPS was a success due to demands of Airbus and the pilot unions? That is some real revisionist history there, it takes quite a lens to see the situation that way. Sadly, Tony Broderick has passed so we can't interview him.

Airbus had the A300 flying trans Atlantic beyond 60 minutes before ETOPS regulations came into effect.

Can you please provide an example of an airline that flew the North Atlantic with the A300B4 and the city pairs?

SteelChair wrote:

zeke wrote:

SteelChair wrote:

ETOPS was a success due to demands of Airbus and the pilot unions? That is some real revisionist history there, it takes quite a lens to see the situation that way. Sadly, Tony Broderick has passed so we can't interview him.

Airbus had the A300 flying trans Atlantic beyond 60 minutes before ETOPS regulations came into effect.

Can you please provide an example of an airline that flew the North Atlantic with the A300B4 and the city pairs?

LH JFK - FRA JFK-DUS
IB MAD -JFK

Thank you, other people aware of the real facts will not go down well.

jetwet1 wrote:

SteelChair wrote:

zeke wrote:

Airbus had the A300 flying trans Atlantic beyond 60 minutes before ETOPS regulations came into effect.

Can you please provide an example of an airline that flew the North Atlantic with the A300B4 and the city pairs?

LH JFK - FRA JFK-DUS
IB MAD -JFK

Thanks, thats very interesting, I've learned something.

No offense, but is there anything in print or online about those operations? Its not that I don't believe you but it might be nice to see "officially." One sees over and over that the A300 was the first "ETOPS compliant" aircraft, which appears to be a direct requote from Airbus PR. I'm not sure what "ETOPS complaint" means when the advisory circular for ETOPS was not written until the 80s, and even Airbus admits in the link by another poster that "ETOPS offically began" then. By "ETOPS compliant," what do they mean exactly? Presence of a hydraulically powered electrical generator? Testing of the APU to ensure inflight restart capability? Testing and monitoring of ETOPS critical systems, including engines? Thats kind of hard to imagine that Airbus did all that work since ETOPS hadn't begun yet, per Airbus's documentation. Its also a little hard to imagine given Airbus's later reticence on ETOPS, ie., wasting time and resources producing the A340, which would ultimately be supplanted by twins.

If true, I'm surprised by LH. I had always heard "unofficially" that there were a prime mover behind the A340. Indeed, they did not get on the ETOPS bandwagon until very late in the game (notwithstanding the operations that you quote, which would have made them very early or first.).

It must have been hard for IB to balance up their fleet, with all those one-way flights to JFK.

The link posted by the other poster (a 1998 Airbus document) is maddeningly short on details, but does include the following: "Airbus operators have been operating their A300 twinjet aircraft across the North Atlantic, the Bay of Bengal and the Indian Ocean under the 90-minute ICAO rule since 1976. However, ETOPS officially began in 1985 with the newly issued ETOPS criteria."

Again, I know A vs B runs deep on these boards. And my position on this issue may set me up to be seen as a B guy. But the reality is that I've been very critical of B on other topics. However, in this case, it seems unlikely that Airbus could have been so strongly ETOPS when Boeing did most of the work (in close coordination with the FAA) in the 80s and 90s establishing ETOPS with the 767-200ER, -300ER, and 777 programs. At the time, it was a very controversial topic, and Airbus was tepid, yet now they publish documents that use terms like "ETOPS compliant" and claim to be an early adopter. I sense an imbalance between their claims and reality.

SteelChair wrote:

No offense, but is there anything in print or online about those operations? Its not that I don't believe you but it might be nice to see "officially." One sees over and over that the A300 was the first "ETOPS compliant" aircraft, which appears to be a direct requote from Airbus PR. I'm not sure what "ETOPS complaint" means when the advisory circular for ETOPS was not written until the 80s, and even Airbus admits in the link by another poster that "ETOPS offically began" then. By "ETOPS compliant," what do they mean exactly?

The ability for twins to fly beyond 60 minutes was a ICAO discussion well before the FAA came up with ETOPS. A number of different regulations implemented the SARPS relating to this, from memory it was JAA, India, and Singapore taking the lead. ETOPS was just the FAA version.

When ETOPS came in, the A300/A310 were automatically grandfathered approvals.

SteelChair wrote:

Presence of a hydraulically powered electrical generator? Testing of the APU to ensure inflight restart capability? Testing and monitoring of ETOPS critical systems, including engines? Thats kind of hard to imagine that Airbus did all that work since ETOPS hadn't begun yet, per Airbus's documentation.

A lot of that has nothing to do with ETOPS, for example you can dispatch a twin ETOPS with an inop APU. ETOPS is not an aircraft level approval, it is an operator specific systems and process approval.

SteelChair wrote:

Its also a little hard to imagine given Airbus's later reticence on ETOPS, ie., wasting time and resources producing the A340, which would ultimately be supplanted by twins.

Look you are reinventing history here, back when the A340 design studies were shown at the trade shows there simply was not an engine big enough to make it a twin. And the engines P&W promised them were more like todays GTF.

The A340-300 was actually competitive against the 77E. We used to have a user on here with the name Pherio who was a captain with Air France, and he could demonstrate numbers on 12 hr legs like CDG JNB where they were neck and neck. Where the 77E had the advantage was on shorter legs and was therefore more versatile.

zeke wrote:

SteelChair wrote:

No offense, but is there anything in print or online about those operations? Its not that I don't believe you but it might be nice to see "officially." One sees over and over that the A300 was the first "ETOPS compliant" aircraft, which appears to be a direct requote from Airbus PR. I'm not sure what "ETOPS complaint" means when the advisory circular for ETOPS was not written until the 80s, and even Airbus admits in the link by another poster that "ETOPS offically began" then. By "ETOPS compliant," what do they mean exactly?

The ability for twins to fly beyond 60 minutes was a ICAO discussion well before the FAA came up with ETOPS. A number of different regulations implemented the SARPS relating to this, from memory it was JAA, India, and Singapore taking the lead. ETOPS was just the FAA version.

When ETOPS came in, the A300/A310 were automatically grandfathered approvals.

Whether or not they were grandfathered doesn't answer any of the questions I posed.

zeke wrote:

SteelChair wrote:

Presence of a hydraulically powered electrical generator? Testing of the APU to ensure inflight restart capability? Testing and monitoring of ETOPS critical systems, including engines? Thats kind of hard to imagine that Airbus did all that work since ETOPS hadn't begun yet, per Airbus's documentation.

A lot of that has nothing to do with ETOPS, for example you can dispatch a twin ETOPS with an inop APU. ETOPS is not an aircraft level approval, it is an operator specific systems and process approval.

There are multiple levels of approval required. Each airframe and engine combination are absolutely required to obtain approval, before operators are even involved. Each operator also requires a separate operational approval. Monitoring ETOPS critical systems is a requirement for the operator.

Regarding the APU specifically, yes, in some cases and dependent upon the airplane ETOPS can be flown with an APU inoperative. Levels may be degraded: 120 mins and APU continuously operated for example, might be a requirement for certain airplane types. It all depends upon the system design/MMEL.

None of this obviates the fact that Airbus and ICAO had no requirements for an inflight restart capability monitoring program, this was required by the FAA, and Boeing. And in some cases (only a single engine mounted generator for each engine ie., 767), start capability of the APU is a highly significant safety feature. One doesn't want to be flying around on a single AC power source. One rarely stated oversight in the whole APU policy is that the APU inlet doesn't have any deicing capability.

zeke wrote:

SteelChair wrote:

Its also a little hard to imagine given Airbus's later reticence on ETOPS, ie., wasting time and resources producing the A340, which would ultimately be supplanted by twins.

Look you are reinventing history here, back when the A340 design studies were shown at the trade shows there simply was not an engine big enough to make it a twin. And the engines P&W promised them were more like todays GTF.

The A340-300 was actually competitive against the 77E. We used to have a user on here with the name Pherio who was a captain with Air France, and he could demonstrate numbers on 12 hr legs like CDG JNB where they were neck and neck. Where the 77E had the advantage was on shorter legs and was therefore more versatile.

A sample value of one isn't very valuable. I remember reading some information that Boeing provided that for a similar level of engine technology a twin was ~5% more efficient than a quad. Sorry, I don't have a link. It is widely accepted in the industry that twins are inherently more efficient than quads. This is so widely accepted that I'm amazed that anyone would argue otherwise.

zeke wrote:

A lot of that has nothing to do with ETOPS, for example you can dispatch a twin ETOPS with an inop APU. ETOPS is not an aircraft level approval, it is an operator specific systems and process approval.

Aircraft can become ETOPS restricted with inoperative equipment. An inoperative APU limits ETOPS capability. The same applies for engine fan case overheat detection systems, main tank fuel pumps, engine anti-ice systems, fuel flow indicators, autothrottle arm switches, IDG, etc.
Just a few examples from our 777 MEL.

If the aircraft (or even a single ETOPS relevant component) is not ETOPS certified, the aircraft cannot fly ETOPS. The operator can have as much ETOPS approval as he wants, the Aircraft still cannot fly ETOPS.

SteelChair wrote:

A sample value of one isn't very valuable. I remember reading some information that Boeing provided that for a similar level of engine technology a twin was ~5% more efficient than a quad. Sorry, I don't have a link. It is widely accepted in the industry that twins are inherently more efficient than quads. This is so widely accepted that I'm amazed that anyone would argue otherwise.

The 77Es larger fuel capacity and therefore range is what helped sell it. We could manage about 40t payload on 14 hour sectors. The A340 was cost competitive:

This cost comparison from flightglobal:

SteelChair wrote:

Whether or not they were grandfathered doesn't answer any of the questions I posed.

They are not really questions, they are ramblings in disbelief that Airbus did something before Boeing. fact is A300/A310s were flying commercially beyond 60 minutes from the mid 1970s. It was not just like a light switch, it was a long progressive set of milestones.

Airbus operators have been operating their A300 twinjet aircraft across the North Atlantic, the Bay of Bengal and the Indian Ocean under the 90-minute ICAO rule since 1976. In June 1985, the first ETOPS operations (90 minutes) were made by Singapore Airlines with an A310. In April1986, PanAm was the first to inaugurate transatlantic revenue service with A310-200 and A310-300 aircraft. In less than five years, more than 20 operators joined the two pioneers in Airbus ETOPS operations.

In March 1990, the A310-324 (PW4000) was the first FADEC engine powered aircraft to receive ETOPS approval by the FAA. At the same time, the A300B4-605R was the first Airbus aircraft to get ETOPS approval for 180 minutes diversion time. By the end of 1991, all A310 and A300-600 were approved for 180 minutes diversion time by the French DGAC.

In September 1991, the A320 was the first fly-by-wire aircraft to be approved for ETOPS operations with 120 minutes diversion time. In April 1994, the A330-301 (CF6-80E1A2 engines) obtained the ETOPS Type Design Approval from the JAA with 120-minute diversion time. This was the first new aircraft to receive early ETOPS approval worldwide. In May 1994, Aer Lingus was the first operator to inaugurate ETOPS operations over the North Atlantic with this model.

In the same time, the A300-600 with CF6-80C2A5F engines (featuring FADEC) obtained the ETOPS Type Design Approval (180-minute diversion time) from the JAA at entry into service.

In November 1994, the A330-300 with Pratt & Whitney engines obtained the ETOPS Type Design Approval from the JAA with 90-minute diversion time at entry into service. The first ETOPS operators were Thai Airways, Malaysian Airlines and LTU. In January 1995, the A330-300 with Rolls-Royce engines obtained the ETOPS Type Design Approval from the JAA with 90-minute diversion time at entry into service.

The A330-300 obtained the ETOPS Type Design Approval from the JAA with 180-minute diversion time (GE engines in February 1995 ; PW engines in August 1995 ; RR engines: in June 1996).

In May 1996 and February 1997, respectively the A321 and A319 obtained the ETOPS Type Design Approval from the JAA with 120 minutes diversion
time.

In April 1998, the A330-200 with GE engines obtained the ETOPS Type Design Approval from the JAA with 180 minutes diversion time prior entry into service.

In 2009, the A330 was the first type to receive ETOPS 240.

SteelChair wrote:

Regarding the APU specifically, yes, in some cases and dependent upon the airplane ETOPS can be flown with an APU inoperative. Levels may be degraded: 120 mins and APU continuously operated for example, might be a requirement for certain airplane types. It all depends upon the system design/MMEL.

APUs are not required for ETOPS, we have no restriction on the A330 or A350 with an inop APU. You cannot even start the APU on a 747 when airborne. The requirement is that engines and APU electrical generators must provide full technical electrical power throughout the normal flight envelope. Every Airbus ETOPS aircraft is equipped with an emergency/standby generator which gives a total of four independent generators. The design intent is to obtain dispatch flexibility when conducting an ETOPS mission.

zeke wrote:

SteelChair wrote:

Regarding the APU specifically, yes, in some cases and dependent upon the airplane ETOPS can be flown with an APU inoperative. Levels may be degraded: 120 mins and APU continuously operated for example, might be a requirement for certain airplane types. It all depends upon the system design/MMEL.

APUs are not required for ETOPS, we have no restriction on the A330 or A350 with an inop APU. You cannot even start the APU on a 747 when airborne. The requirement is that engines and APU electrical generators must provide full technical electrical power throughout the normal flight envelope. Every Airbus ETOPS aircraft is equipped with an emergency/standby generator which gives a total of four independent generators. The design intent is to obtain dispatch flexibility when conducting an ETOPS mission.

You say that the APU is not required for ETOPS and then only quote the A330 and A350. As if they were the only airplanes flying ETOPS.

And just to be sure, are you saying that the 330 can fly unrestricted out to the maximum limit with the APU on MEL? If memory serves, the is a time reduction reduction for the 330 but I confess I may be wrong.

The 747 has four engines....so yeah the APU is really auxiliary. Many versions don't have a RAT either. So what? The 350 has 2 generators on each engine so that explains the reason for less dependence on an operable APU.

Thanks for the long history in the other post. One thing I noticed that was lacking was the total number of ETOPS flights completed compared to Boeing. I don’t have that number but it would be interesting. My GUESS is that Boeing did a very large proportion of the total ETOPS flights up to 1995-2000. Even today, I doubt Airbus has caught up. 767-200s and 767-300ERs did a very large number if crossings before the the 330 arrived in any significant numbers, and the 310 was a niche aircraft.

Horstroad wrote:

Aircraft can become ETOPS restricted with inoperative equipment. An inoperative APU limits ETOPS capability. The same applies for engine fan case overheat detection systems, main tank fuel pumps, engine anti-ice systems, fuel flow indicators, autothrottle arm switches, IDG, etc.
Just a few examples from our 777 MEL.

If the aircraft (or even a single ETOPS relevant component) is not ETOPS certified, the aircraft cannot fly ETOPS. The operator can have as much ETOPS approval as he wants, the Aircraft still cannot fly ETOPS.

That is type specific, The A350 for example does not have such limits, each engine has 2 generators.

Yes I agree with your comments about using unapproved parts, that is more of an issue for operators who have mixed fleets of ETOPS and Non ETOPS of the same type. All of our widebodies (including 747) are ETOPS.

SteelChair wrote:

And just to be sure, are you saying that the 330 can fly unrestricted out to the maximum limit with the APU on MEL? If memory serves, the is a time reduction reduction for the 330 but I confess I may be wrong.

We have no limit in our A330 MEL for an inop APU, however we only have ETOPS 180 on the A330, I think the APU is required for beyond ETOPS 180 (ie anything above 207 minutes).

zeke wrote:

SteelChair wrote:

And just to be sure, are you saying that the 330 can fly unrestricted out to the maximum limit with the APU on MEL? If memory serves, the is a time reduction reduction for the 330 but I confess I may be wrong.

We have no limit in our A330 MEL for an inop APU, however we only have ETOPS 180 on the A330, I think the APU is required for beyond ETOPS 180 (ie anything above 207 minutes).

So it's taken quite a few posts to get to concurrence on what several posters said already: that the limitations vary by the airplane (based upon the design of the systems on those planes). I think blanket statements like "there are no ETOPS limits for APU inop," and "ETOPS is not an airplane level approval, only operators are approved for ETOPS" should be avoided.

SteelChair wrote:

I think blanket statements like "there are no ETOPS limits for APU inop,

Which is correct, there is nothing in the ETOPS regulations that says that an aircraft must have an APU. It is about system redundancy, how that is achieved varies.

"ATA 24 ELECTRICAL
A minimum of three independent sources of electrical power are required. Those sources typically include a combination of engine-driven generators, auxiliary power unit (APU)-driven generator(s), and/or backup electrical power source(s)."

As i said above, every Airbus ETOPS aircraft is equipped with an emergency/standby generator which gives a minimum of four independent generators. The design intent is to obtain dispatch flexibility when conducting an ETOPS mission. That means dispatch with an inop APU is possible for an ETOPS flight. You are not prevented from ETOPS with an inop APU as long as the requirement for "three independent sources of electrical power" is achieved.

SteelChair wrote:

"ETOPS is not an airplane level approval

It isn't, you can take a brand new A350 to a operator and that does not give them ETOPS approval. The approval for ETOPS does not sit with the manufacturer or the type certificate (this makes them ETOPS capable rather than ETOPS approved), the approval sits with the operator. It is an operational approval, the same as LVO, RNP, LASO, polor ops, ILS/PRM etc. Regardless of the airframe has the required systems installed (ie ETOPS capability) when manufactured at the factory, it is no automatic right to conduct those operations (ie it does not grant the approval).

zeke wrote:

SteelChair wrote:

I think blanket statements like "there are no ETOPS limits for APU inop,

Which is correct, there is nothing in the ETOPS regulations that says that an aircraft must have an APU. It is about system redundancy, how that is achieved varies.

"ATA 24 ELECTRICAL
A minimum of three independent sources of electrical power are required. Those sources typically include a combination of engine-driven generators, auxiliary power unit (APU)-driven generator(s), and/or backup electrical power source(s)."

As i said above, every Airbus ETOPS aircraft is equipped with an emergency/standby generator which gives a minimum of four independent generators. The design intent is to obtain dispatch flexibility when conducting an ETOPS mission. That means dispatch with an inop APU is possible for an ETOPS flight. You are not prevented from ETOPS with an inop APU as long as the requirement for "three independent sources of electrical power" is achieved.

SteelChair wrote:

"ETOPS is not an airplane level approval

It isn't, you can take a brand new A350 to a operator and that does not give them ETOPS approval. The approval for ETOPS does not sit with the manufacturer or the type certificate (this makes them ETOPS capable rather than ETOPS approved), the approval sits with the operator. It is an operational approval, the same as LVO, RNP, LASO, polor ops, ILS/PRM etc. Regardless of the airframe has the required systems installed (ie ETOPS capability) when manufactured at the factory, it is no automatic right to conduct those operations (ie it does not grant the approval).

Keep trying. You are getting closer.

On a 767 the HMG (Airbus uses a different acronym) does not "count"as a power source for determining dispatch with a generator inop. Its dinky. It only outputs 5kw as opposed to 120 for a main engine or APU gen. It basically keeps the battery from draining. Thus you have only 3 power sources. You can launch with a main engine gen on MEL (youre down to 2 now) but there is a downgrade to 120 minutes. The HMG doesn't count as a primary power source due to its small output.

Some ETOPS generator scenarios are discussed here: viewtopic.php?t=772609

You're not even close on paragraph 2, or youre playing word games. If an airplane/engine combination isn't designed and approved for ETOPS, an operator can't get operational approval. This is basic. I'm not sure what you aren't understanding here. Let's say that hypothetically the A390 equipped with RR Severn engines went through certification testing and failed the ETOPS portion. An airline couldn't even apply for operational approval because the airplane to use your words isn't "capable."

No word games at all. I do this for a living. 120 minutes is still ETOPS, for some airlines that’s all they need and approved for, it might have no operational impact.

On the A330, only one generator is required to power the whole aircraft. In the event of all 3 (2xeng and APU) of them failing the emergency generator will power enough systems for the pressurisation, FMC, navigation, VHF/HF communication, smoke and fire detection/extinguisher, flight control computers, ice protection etc Non essential items are automatically shed.

There is absolutely no requirement for everything to remain powered in an ETOPS scenario. There is no requirement to start the APU like it’s stated in that thread for the 767.

Nor is there any requirement for every airline to obtain ETOPS approvals to the maximum an aircraft is capable of, for some airlines they don’t get the approval at all.

Classic case of obfuscation. You answer questions that aren't asked and don't directly answer questions that are asked. You infer statements that weren't made.

Every airframe/engine combination has to be certified/ approved for certain levels of ETOPS BEFORE any operator can apply for operational approval from their safety regulator.

MELs contain specific instructions for each airplane type. Limitations are different based upon systems design. Some airplanes have certain ETOPS restrictions/downgrades based upon operation with a generator inop. The MEL has to be followed.

QRHs also contain specific information based upon the airplane type/system design. Enroute, if an engine generator fails, the QRH usually (dependent upon airplane type) says to start the APU. If the APU generator can't be brought on line, that is a LAND NEARSET SUITABLE for some airplane types.

HMG (CSM/G) doesn't count as a primary power source when looking at the MEL.

A lot of us do this for a living, and have for a long time.

Chaostheory wrote:

SteelChair wrote:

A sample value of one isn't very valuable. I remember reading some information that Boeing provided that for a similar level of engine technology a twin was ~5% more efficient than a quad. Sorry, I don't have a link. It is widely accepted in the industry that twins are inherently more efficient than quads. This is so widely accepted that I'm amazed that anyone would argue otherwise.

The 77Es larger fuel capacity and therefore range is what helped sell it. We could manage about 40t payload on 14 hour sectors. The A340 was cost competitive:

This cost comparison from flightglobal:

Aviation Week May 9, 2005, page 46: "777-300ER/200LR have a 6-8% fuel burn advantage over A340-500/600." They mention not only weight advantage but also aerodynamic advantage due to 2 engines versus 4.

SteelChair wrote:

Chaostheory wrote:

SteelChair wrote:

A sample value of one isn't very valuable. I remember reading some information that Boeing provided that for a similar level of engine technology a twin was ~5% more efficient than a quad. Sorry, I don't have a link. It is widely accepted in the industry that twins are inherently more efficient than quads. This is so widely accepted that I'm amazed that anyone would argue otherwise.

The 77Es larger fuel capacity and therefore range is what helped sell it. We could manage about 40t payload on 14 hour sectors. The A340 was cost competitive:

This cost comparison from flightglobal:

Aviation Week May 9, 2005, page 46: "777-300ER/200LR have a 6-8% fuel burn advantage over A340-500/600." They mention not only weight advantage but also aerodynamic advantage due to 2 engines versus 4.

Aircraft Technology Engineering and Maintenance June-July 2000 pages 33 and 34 has Boeing data claiming a similar advantage for the same airplane types. It's Boeing data so probably skewed towards them a little bit. Airbus may have similar data showing the advantage their way. Just haven't found it yet.

SteelChair wrote:

Some airplanes have certain ETOPS restrictions/downgrades based upon operation with a generator inop. The MEL has to be followed.

Sure, however they can still be dispatched ETOPS. For the 767 example you keep bringing up, 120 minutes is still enough to fly TATL, Europe to South America, Australia/NZ to Asia, Middle East to Asia. 120 minutes for the 767 still covers most of the globe. 180/207 minutes on the A330 means transpacific is also available. It is not as restrictive as you are trying to make out, the aircraft can still be dispatched ETOPS.

SteelChair wrote:

if an engine generator fails, the QRH usually (dependent upon airplane type) says to start the APU. If the APU generator can't be brought on line, that is a LAND NEARSET SUITABLE for some airplane types.

Start the APU in the QRH is not a requirement for the 787/747/A320/A330/A340/A350/A380.

SteelChair wrote:

HMG (CSM/G) doesn't count as a primary power source when looking at the MEL.

What type are you referring to ?

most aircraft do not have a "HMG"

zeke wrote:

SteelChair wrote:

HMG (CSM/G) doesn't count as a primary power source when looking at the MEL.

What type are you referring to ?

most aircraft do not have a "HMG"

A previous post would seem to suggest he's referring to the 767.

AirKevin wrote:

zeke wrote:

SteelChair wrote:

HMG (CSM/G) doesn't count as a primary power source when looking at the MEL.

What type are you referring to ?

most aircraft do not have a "HMG"

A previous post would seem to suggest he's referring to the 767.

HMG and CSM/G do not count as a PRIMARY electrical power source on any airplane.

Really, to post as someone very informed on these topics ("I do this for a living") and not know what a HMG is or which airplanes it is installed on is almost embarrassing (for you). I suppose next I will have to explain what a PMA or am SCU is. These, and many other systems, were very important when Boeing was blazing the trail on ETOPS.

Where does this "PRIMARY" wording come from ?

FAR 25 Appendix K just says "(b) Electrical power supply. The airplane must be equipped with at least three independent sources of electrical power."

The standby generator on Airbus aircraft meet the ETOPS requirements, an APU is not required to meet the requirements, it says "(b) APU design. If an APU is needed to comply with this appendix, the applicant must demonstrate that.......".

What the independent electrical generators need to be able to power is as follows :

"Electrical Power Availability/Reliability.
In the L25.2(a)(ii) context, an electrical power supply system includes any non-time limited electrical generator, whether driven by the aircraft engines, an
auxiliary power unit, a hydraulic motor, or a ram air turbine, as long as the generator produces sufficient power for the equipment discussed below. It may
also include time-limited sources (i.e. batteries), if the duration of the batteries is accounted for in the analysis.

Electrically powered functions required for continued safe flight and landing of an ETOPS flight normally include critical:
flight instrumentation,
warning systems,
engine controls,
fuel distribution necessary to complete the flight or a diversion
communications or critical navigation systems,
route or destination guidance equipment,
fire protection (cargo, APU and engine),
ice protection,
equipment cooling,
airplane environmental control and
any other critical equipment necessary for ETOPS.
Typically equipment providing critical functions is on the airplane’s standbyvelectrical bus. For fly-by-wire aircraft, this also includes the critical flight control
system. In today's state-of-the art airplanes, a minimum of three electrical powervsupply sources are necessary to meet this requirement. Electrically powered functions required to maintain the capability of the airplane or the ability of the crew to cope with adverse operating conditions for an ETOPS flight normally includes essential:
flightdeck and instrument lighting,
captain and first officer instruments,
engine inoperative auto-pilot,
any other essential equipment necessary for ETOPS"

zeke wrote:

SteelChair wrote:

And just to be sure, are you saying that the 330 can fly unrestricted out to the maximum limit with the APU on MEL? If memory serves, the is a time reduction reduction for the 330 but I confess I may be wrong.

We have no limit in our A330 MEL for an inop APU, however we only have ETOPS 180 on the A330, I think the APU is required for beyond ETOPS 180 (ie anything above 207 minutes).

Correct. APU only required for Beyond 180 Min ETOPS. No restriction for 180 Min ETOPS.

T54A wrote:

zeke wrote:

SteelChair wrote:

And just to be sure, are you saying that the 330 can fly unrestricted out to the maximum limit with the APU on MEL? If memory serves, the is a time reduction reduction for the 330 but I confess I may be wrong.

We have no limit in our A330 MEL for an inop APU, however we only have ETOPS 180 on the A330, I think the APU is required for beyond ETOPS 180 (ie anything above 207 minutes).

Correct. APU only required for Beyond 180 Min ETOPS. No restriction for 180 Min ETOPS.

Which types require the APU to actually be running during the ETOPS portion? I know the B737 I believe does?

zeke wrote:

Where does this "PRIMARY" wording come from ?

FAR 25 Appendix K just says "(b) Electrical power supply. The airplane must be equipped with at least three independent sources of electrical power."

The standby generator on Airbus aircraft meet the ETOPS requirements, an APU is not required to meet the requirements, it says "(b) APU design. If an APU is needed to comply with this appendix, the applicant must demonstrate that.......".

What the independent electrical generators need to be able to power is as follows :

"Electrical Power Availability/Reliability.
In the L25.2(a)(ii) context, an electrical power supply system includes any non-time limited electrical generator, whether driven by the aircraft engines, an
auxiliary power unit, a hydraulic motor, or a ram air turbine, as long as the generator produces sufficient power for the equipment discussed below. It may
also include time-limited sources (i.e. batteries), if the duration of the batteries is accounted for in the analysis.

Electrically powered functions required for continued safe flight and landing of an ETOPS flight normally include critical:
flight instrumentation,
warning systems,
engine controls,
fuel distribution necessary to complete the flight or a diversion
communications or critical navigation systems,
route or destination guidance equipment,
fire protection (cargo, APU and engine),
ice protection,
equipment cooling,
airplane environmental control and
any other critical equipment necessary for ETOPS.
Typically equipment providing critical functions is on the airplane’s standbyvelectrical bus. For fly-by-wire aircraft, this also includes the critical flight control
system. In today's state-of-the art airplanes, a minimum of three electrical powervsupply sources are necessary to meet this requirement. Electrically powered functions required to maintain the capability of the airplane or the ability of the crew to cope with adverse operating conditions for an ETOPS flight normally includes essential:
flightdeck and instrument lighting,
captain and first officer instruments,
engine inoperative auto-pilot,
any other essential equipment necessary for ETOPS"

I've seen it in airline operational manuals.

If 3 generators are required for ETOPS, and you are talking about an airplane that only has one engine generator per engine, and there are no other generators other than the dinky hydraulically powered generator, then the APU generator becomes a requirement. Thus the APU is a requirement. On some airplanes, there is no other 3rd generator because the HMG doesn't count. If the APU or a main engine generator is inoperative you may still be able to launch with some restrictions. This is very basic airline operational stuff, I'm not sure what the source of your confusion is.

The only time a standby generator does not count (normal ETOPS) as “independent power source” is when it is unable to meet the demands of the systems required to be available. Many standby generators can meet that requirement, eg the A330.

The 767 example you keep bringing up by your own admission has an inadequate standby generator output to meet the demand for ETOPS systems so as you have suggested the APU is required. You cannot draw an inference that it is therefore required on all aircraft.

The A320 for example is limited to 120 minute ETOPS with an APU inop, that is not a function of inadequate output of the generator to power systems, it is due to avionics cooling demand.

IIRC the CSM/G is also a dinky 5kw unit. Barely enough to keep the battery charged, the Captains instruments and a few of the flight control computers operating. I've never known of an incident whereby any airplane was down to that generator. If you're down to that, you're in serious trouble.

This whole discussion was started because the advisory circular introduced the idea of "ETOPS critical systems," of which the electrical system is only one. AC 120-42 really specified in detail many of these considerations and over the subsequent years I've heard the FAA effort on that AC characterized as a textbook case of safety regulation. The truth is that Boeing and the FAA should be commended for their efforts on ETOPS at a time when other manufacturers were taking quads to airshows painted up with "4 engines 4 the long haul."

Many knowledgeable people thought ETOPS was a bad idea in the 80s and they were all wrong. More than 40 years later, after millions of ETOPS crossings, not a single flight has crashed due to dual engine failure. (Air Transat was fuel starvation, totally unrelated to number of engines, and also the pilots manually opened the crossfeed.)

SteelChair wrote:

IIRC the CSM/G is also a dinky 5kw unit. Barely enough to keep the battery charged, the Captains instruments and a few of the flight control computers operating. I've never known of an incident whereby any airplane was down to that generator. If you're down to that, you're in serious trouble.

This whole discussion was started because the advisory circular introduced the idea of "ETOPS critical systems," of which the electrical system is only one. AC 120-42 really specified in detail many of these considerations and over the subsequent years I've heard the FAA effort on that AC characterized as a textbook case of safety regulation. The truth is that Boeing and the FAA should be commended for their efforts on ETOPS at a time when other manufacturers were taking quads to airshows painted up with "4 engines 4 the long haul."

Many knowledgeable people thought ETOPS was a bad idea in the 80s and they were all wrong. More than 40 years later, after millions of ETOPS crossings, not a single flight has crashed due to dual engine failure. (Air Transat was fuel starvation, totally unrelated to number of engines, and also the pilots manually opened the crossfeed.)

Nitpicking, but BA38 crashed due to a dual engine failure (although that was a correlated event, affecting all two engines)

kalvado wrote:

SteelChair wrote:

IIRC the CSM/G is also a dinky 5kw unit. Barely enough to keep the battery charged, the Captains instruments and a few of the flight control computers operating. I've never known of an incident whereby any airplane was down to that generator. If you're down to that, you're in serious trouble.

This whole discussion was started because the advisory circular introduced the idea of "ETOPS critical systems," of which the electrical system is only one. AC 120-42 really specified in detail many of these considerations and over the subsequent years I've heard the FAA effort on that AC characterized as a textbook case of safety regulation. The truth is that Boeing and the FAA should be commended for their efforts on ETOPS at a time when other manufacturers were taking quads to airshows painted up with "4 engines 4 the long haul."

Many knowledgeable people thought ETOPS was a bad idea in the 80s and they were all wrong. More than 40 years later, after millions of ETOPS crossings, not a single flight has crashed due to dual engine failure. (Air Transat was fuel starvation, totally unrelated to number of engines, and also the pilots manually opened the crossfeed.)

Nitpicking, but BA38 crashed due to a dual engine failure (although that was a correlated event, affecting all two engines)

That's true, but that failure scenario was not in the ETOPS portion of flight, and really had nothing to do with ETOPS. If it had been a quad the result would have been the same. If it had 12 engines, the result would have been the same.

zeke wrote:

kalvado wrote:

What you say is second approach becomes dominant. As a passenger who prefers getting to the destination in one piece (and hence from the regulator standpoint) that's fine as long as it works. So shutdown statistics in that monitoring scenario may not tell airline cost story, but it definitely tells the expected crash rate story (a pretty optimistic one!)

So you have two aircraft side by side, one set of engine been on with 100,000 hrs each, no damage, no failure. And another aircraft that has had its engines replaced at 20,000 hrs, it’s on its 5th set of engines. No engine failure with each engine.

They both have the same reliability on paper.
etops engines are on trend monitoring at most if not all the Major airlines monitor the takeoff EPR vs EGT/ or N1 vs EGT the Climb power and cruise EGT or PS3 pressure oil temp and other parameters that indicate the engine internal condition. engines normally do not just fail unless the reason is external like a bird down the hatch. . ETOPS engines are monitored and usually changed before they get out of hand and their life can be extended by changing out a module. we've in the past had engines that stayed on the wing for 20,000 hours before their complete overhaul because once you have to work on the compressor the game is over, Someties an engine is wapped to a non ETOPS airplane if the fleet uses the same engine model for ETOPS and non-ETOPS models.

strfyr51 wrote:

zeke wrote:

kalvado wrote:

What you say is second approach becomes dominant. As a passenger who prefers getting to the destination in one piece (and hence from the regulator standpoint) that's fine as long as it works. So shutdown statistics in that monitoring scenario may not tell airline cost story, but it definitely tells the expected crash rate story (a pretty optimistic one!)

So you have two aircraft side by side, one set of engine been on with 100,000 hrs each, no damage, no failure. And another aircraft that has had its engines replaced at 20,000 hrs, it’s on its 5th set of engines. No engine failure with each engine.

They both have the same reliability on paper.
etops engines are on trend monitoring at most if not all the Major airlines monitor the takeoff EPR vs EGT/ or N1 vs EGT the Climb power and cruise EGT or PS3 pressure oil temp and other parameters that indicate the engine internal condition. engines normally do not just fail unless the reason is external like a bird down the hatch. . ETOPS engines are monitored and usually changed before they get out of hand and their life can be extended by changing out a module. we've in the past had engines that stayed on the wing for 20,000 hours before their complete overhaul because once you have to work on the compressor the game is over, Someties an engine is wapped to a non ETOPS airplane if the fleet uses the same engine model for ETOPS and non-ETOPS models.

Some more detail: all engines are on trend monitoring since the industry transitioned from an hard time overhaul based limit to "on condition" 40 to 50 years ago. Many more parameters other than just those listed also tracked. In a way the on condition monitoring could be thought of as the 1st generation of airplane health monitoring. since many valves pumps and other components on the airplanes are run on condition, the newest airplanes monitor thousands of parameters all the time with the whole goal of getting the full economic life out of the component but changing it just before it fails.

The difference with etop's engines is that they are monitored to closer tolerances, and changed or other work done on them more aggressively than on non etops engines. also the parts are dedicated etops parts, and the mechanics all have to be trained on etops.

It's a multilayered approach that is a testament to the groundbreaking work that the FAA did under Tony Broderick amd with the assistance of Boeing.