Moderators: richierich, ua900, PanAm_DC10, hOMSaR
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.
Starlionblue wrote:AFAIK, "4 Engines 4 Long Haul" was more or a Virgin Atlantic marketing gimmick than something Airbus pushed really strongly.
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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»
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.
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.
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.
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.
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!)
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.
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.
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.
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?
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
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?
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.
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.
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.
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.
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.
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.
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.
SteelChair wrote:Whether or not they were grandfathered doesn't answer any of the questions I posed.
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.
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.
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.
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.
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).
SteelChair wrote:I think blanket statements like "there are no ETOPS limits for APU inop,
SteelChair wrote:"ETOPS is not an airplane level 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).
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:
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.
SteelChair wrote:Some airplanes have certain ETOPS restrictions/downgrades based upon operation with a generator inop. The MEL has to be followed.
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.
SteelChair wrote:HMG (CSM/G) doesn't count as a primary power source when looking at the MEL.
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"
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.
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).
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.
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"
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.)
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)
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!)
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.