Losing Both Engines on a 777

[michal 44]

>True that modern jet engine reliability has improved over the>years, but that is NOT THE ONLY CAUSE (reason) for ETOPS.And who said it was? Of coures the main driver for ETOPS is efficiency of twin-engine aircraft. Engine reliability is something that makes it possible.>But they are NOT indicative of the odds that an aircraft may>need to be near to an airport after suffering engine>failures/shutdowns. To use them for trying to establish ETOPS>is misleading.Sorry I don't understand the meaning of that.>A twin engine Piper had to ditch at sea because>only one engine failed. Flying on a single engine it simply>ran out of fuel! Again, I fail to see connection with the topic. This Piper could have had 4 engines and it would make absolutely no difference.Michael J.

[michal 44]

>I'd be hard pressed to actually find a case of any>incident/accident in the past 20 years where multiple engine>failures had totally unrelated causes.>Correct. Whether you go back 20 years or 60 years - it never happened. Michael J.http://www.precisionmanuals.com/images/for...argo_hauler.gifhttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg

[elche 5]

In the worst aviation accident in South Australia for 28 years, a Navajo had multiple-engine failure crashing into the Spencer Gulf.Although the loss of both engines in this accident seem to be related, there is a small possibility that the loss of the right engine may have been caused by other reasons.* "left engine failed first as a result of a fatigue crack in the crankshaft."* "It is likely that because of the increased power demanded of the right engine after the left engine failed, abnormal combustion (detonation) occurred and rapidly raised the temperature of the pistons and cylinder heads. As a result, a hole melted in the number 6 piston causing loss of engine power and erratic engine operation."Taken from Flight Safety Australia Magazine - January/February 2002 issue

Have a great Day/Night where ever you are! :-wave

http://www.3dflite.com/dac/img/BANNER-soccer.gif Student Pilot - YSBKC152/Tomahawk/Warrior/Archer/Duchess66.3 hrs Total

[michal 44]

Navajo - not exactly your typical "airliner" ;) . I know folks are trying hard to come up with a counterexample - wish you luck.Michael J.http://www.precisionmanuals.com/images/for...argo_hauler.gifhttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg

[elche 5]

"I know folks are trying hard to come up with a counterexample - wish you luck."Not trying to come up with a counterexample. I know a Navajo ain't a 777, but multiple-engine loss is multiple-engine loss regardless of it being piston, turpoprop or a turbine.

Have a great Day/Night where ever you are! :-wave

http://www.3dflite.com/dac/img/BANNER-soccer.gif Student Pilot - YSBKC152/Tomahawk/Warrior/Archer/Duchess66.3 hrs Total

[michal 44]

By the way piston engines were never in the same league of reliability as turbine engines. But even with this qualifier one can't find an example of a two-unrelated-engine failure on early days airliners like a DC3/4, etc.Michael J.http://www.precisionmanuals.com/images/for...argo_hauler.gifhttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg

[Geofa 108]

If you read "Fate is the hunter" (one of my favorite books) by Ernest Gann-he documents all 4 engines failing on a DC 4A-(they were able to restart them for occasional time periods to get back once they got below 3000 ft.-was a problem with the engines not working at altitude)...An earlier chapter also documents a similar venture with 3 out of 4 engines quiting on a C-54 due to incorrect spark plugs.http://mywebpages.comcast.net/geofa/pages/rxp-pilot.jpg

[Murmur 3,941]

>>In the worst aviation accident in South Australia for 28>years, a Navajo had multiple-engine failure crashing into the>Spencer Gulf.>>Although the loss of both engines in this accident seem to be>related, there is a small possibility that the loss of the>right engine may have been caused by other reasons.But a Navajo is not ETOPS certified!Marco

[Roger Mazengarb 0]

G'day Michael,Now go back and calculate the odds of multiple engine failures on an aircraft for ANY reason. They are the true odds that should be considered for ETOPS I can assure you they will be condiderably lower than the odds you are quoting for unrelated reasons. Whenever restrictive controls are set in place there is always a drive by vested interests to whittle away at them.ETOPS was enacted for my interests and as a passenger my safety comes ahead of some engine manufacturers concocted reliabilty figures or airlines bottom line :-)Cheers,Roger

[michal 44]

>Now go back and calculate the odds of multiple engine failures>on an aircraft for ANY reason. They are the true odds that>should be considered for ETOPSThey are. And they will be not much different than for a 4-engine aircraft and that's the whole point of this discussion. Once you start looking at certain other types of failures number of engines have little to do with your final odds. Michael J.http://www.precisionmanuals.com/images/for...argo_hauler.gifhttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg

[Roger Mazengarb 0]

G'day Michael,>They are. And they will be not much different than for a>4-engine aircraft and that's the whole point of this>discussion. Once you start looking at certain other types of>failures number of engines have little to do with your final>odds. Accepting the augument that engine reliability is the only factor:-A 4 engine aircraft will always have a far less chance of total engine failure than a twin.adding unrelated causes would apply equally to all cases so the above would still be true.What your post is implying is that reliability of the gas turbine engines today is such that the greater odds of total engine failure of a twin is an acceptable risk.Cheers,Roger

[michal 44]

>What your post is implying is that reliability of the gas>turbine engines today is such that the greater odds of total>engine failure of a twin is an acceptable risk.To be precise, what my post is implying is that reliability of todays gas turbine egnines is such that other failure scenarios or accident causes dwarf the extra "risk" associated with having no more than 2 engines. In other words having say 4 instead of 2 engines makes you only infinitesimally safer since other factors (not related to number of engines) play dominant role.Michael J.

[RFields5421 1]

Correct me if I'm wrong - but I thought the entire concept behing ETOPS and other standards was to ensure the ability of the aircraft to land safely AFTER THE LOSS OF AN ENGINEThe odds of losing both engines due to unrelated causes are not relevant to the discussion.The odds of losing an ADDITONAL engine due to ANY CAUSES, related or un-related to the original failure, are relevant.It will not take long to find several instances where a second engine failure occured while the aircrew was working the first problem.But the whole point behind ETOPS is how far can a B777 or an A330 safely fly on one engine - without causing enough additional stress upon the engine and airframe.Points which haven't been discussed but are critical include total aircraft weight at the time of the engine loss, fuel load, fuel burn rates at various altitudes, ability of the aircraft to hold altitude -- any altitude, etc.The Navajo reference is relevant - though not predictive. Over stress of remaining engine(s) is a concern.I know after we landed at Danang - all four engines on the Connie were changed. #3 & #4 were changed because of concerns about possible damage.True they were recips and with many more moving parts more prone to failure. But I'll also go back to those days. When one of our EP-3's would lose a turbine (turboprop) engine - the aircraft returned to base. Even though normal patrol practice was to shut down one engine to conserve fuel and extend time on station.Even in a hostile situation, there was a significant difference in procedure for a planned three engine flight, and an unplanned three engine flight.I'm not sure today's four engined long range jet aircraft are significantly more "safe" than twins on those long over water legs.They just seem safer to me.But if a major accident ever occurs due to a long range twin going down at sea - at a distance where the stricter ETOPS standard would have put the aircraft within range of land - the lawyers will bankrupt the airline and the manufacturer.

[Guest jboweruk]

If an A330 can go 89 NM with no engines that's pretty good. As to the guy that said his safety comes above any engine manufacturers 'concocted' safety figures, sorry buddy you're so wrong, you pay to go on a plane, then the CAA, FAA or whatever way your life, and compensation figures against the cost of rectifying 'any' fault on the plane, and go with the cheapest option which 9 times out of 10 is the compensation your family get if you die in a plane crash along with 300 odd other bods.

[michal 44]

>Correct me if I'm wrong - but I thought the entire concept>behing ETOPS and other standards was to ensure the ability of>the aircraft to land safely AFTER THE LOSS OF AN>ENGINEReggie, sory to say but you are wrong. Whether we are talking about loss of another engine after the first one or we are talking about loss of both engines on a trip - this is the exact same thing. In both cases "unrelated cause" principle applies. These are not times of "Connie" where losing an engine may cause other engines to work harder and fail.Michael J.http://www.precisionmanuals.com/images/for...argo_hauler.gifhttp://sales.hifisim.com/pub-download/asv6-banner-beta.jpg