Irrational: I avoid 2-engine 777 transpacific
Nov 1, 2006 | 8:51 pm
#32
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Originally Posted by globetrekker84
Here's a little bit of reading that you might find enlightening:
23 July 1983; Air Canada 767; near Gimli, Manitoba: The aircraft ran out of fuel ...
19 August 1983; United Air Lines 767-200; near Denver, CO: Fuel contamination ...
31 March 1986; United Air Lines 767-200; San Francisco, CA: The engines were inadvertently deactivated...
30 June 1987; Delta Air Lines 767-200; Los Angeles, CA: The engines were inadvertently shut off ...
23 November 1996; Ethiopian Airlines 767-200ER; ... dual engine shutdown due to fuel exhaustion. ...
23 July 1983; Air Canada 767; near Gimli, Manitoba: The aircraft ran out of fuel ...
19 August 1983; United Air Lines 767-200; near Denver, CO: Fuel contamination ...
31 March 1986; United Air Lines 767-200; San Francisco, CA: The engines were inadvertently deactivated...
30 June 1987; Delta Air Lines 767-200; Los Angeles, CA: The engines were inadvertently shut off ...
23 November 1996; Ethiopian Airlines 767-200ER; ... dual engine shutdown due to fuel exhaustion. ...
Originally Posted by alanh
Anyway, I don't know of any all engines out failure on a twin that would have been helped by an extra engine or two.
Nov 1, 2006 | 8:51 pm
#33
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Originally Posted by globetrekker84
Here's a little bit of reading that you might find enlightening:
4 March 2001; United Air Lines 767; near Kona, HI: While early reports indicated that this 767 had a complete loss of power in both engines, the analysis of the flight data recorder by the NTSB does not support this conclusion. According to early FAA and media reports, United Flight 42 took off from Kahului on the Hawaiian island of Maui on a flight to Los Angeles and experienced a dual-engine shutdown about 70 miles (112 km) into the flight, followed by an in-flight restart and a diversion to the Kona airport. Later analysis of the flight data recorder by the NTSB showed that both engines had a reduction of power to below idle, but did not show any evidence of a complete loss of power in either engine. However, there was roughly a 30-second gap in the data during the time when the engines were operating at reduced power. The aircraft, registration number N666UA, has since been returned to service.
Other 767 aircraft have experienced dual engine shutdowns on at least five other occasions:
23 July 1983; Air Canada 767; near Gimli, Manitoba: The aircraft ran out of fuel after the crew miscalculated the weight of fuel on board. The aircraft made an emergency landing on an abandoned airfield. There were no serious injuries.
23 July 1983; Air Canada 767; near Gimli, Manitoba: The aircraft ran out of fuel after the crew miscalculated the weight of fuel on board. The aircraft made an emergency landing on an abandoned airfield. There were no serious injuries.
19 August 1983; United Air Lines 767-200; near Denver, CO: Fuel contamination led to a dual-engine shutdown at about 41,000 feet. The crew restarted the engines at about 15,000 feet.
31 March 1986; United Air Lines 767-200; San Francisco, CA: The engines were inadvertently deactivated the engines during climb at about 3,000 feet. The crew was able to restart the engines and returned to the departure airport.
30 June 1987; Delta Air Lines 767-200; Los Angeles, CA: The engines were inadvertently shut off during climb at about 2,000 feet. The crew was able to restart the engines at about 500 feet and continued to their original destination of Cincinnati.
23 November 1996; Ethiopian Airlines 767-200ER; near Moroni, Comoros Islands: The aircraft was on a flight from Ethiopia to Kenya when it was hijacked. The hijackers refused to allow the aircraft to refuel, leading to a dual engine shutdown due to fuel exhaustion. Ten of the 12 crew members and 117 of the 160 passengers were killed during a subsequent ditching. The three hijackers apparently died.
Nov 1, 2006 | 10:16 pm
#34
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Originally Posted by globetrekker84
Here's a little bit of reading that you might find enlightening . . .
I personally have no problem with transoceanic flights on airplanes equipped with two engines, although I would be rather uncomfortable to find myself on board such an aircraft with both engines failing over the middle of a large body of water.
Remember that increasing the number of engines increases the statistical likelihood of one engine failing. Moreover, it is my understanding that a dual engine failure on a four engine Boeing 747 with a passenger and cargo load of any significance would not permit the aircraft to retain its altitude.
Nov 2, 2006 | 1:30 am
#35
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Originally Posted by globetrekker84
Here's a little bit of reading that you might find enlightening:
4 March 2001; United Air Lines 767; near Kona, HI: ... The aircraft, registration number N666UA, has since been returned to service.
4 March 2001; United Air Lines 767; near Kona, HI: ... The aircraft, registration number N666UA, has since been returned to service.
I saw that made-for-TV Gimli Glider movie last week: Freefall: Flight 174 . Kinda funny made-for-tv Canadian movie...
Nov 2, 2006 | 2:02 am
#36
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Originally Posted by Braniff
Statistically, that would make it dangerous to fly one now. 
Originally Posted by CPRich
Pardon my ignorance, but with a 3 or 4 engine plane, how many engines does the plane need to remain in flight? N-1? or fewer? It's been a while since I did Stats, but I'm pretty sure a 4 engine plane is more likely to lose 1 engine than a 2 engine plane, no?
Originally Posted by mahasamatman
You can prove (or disprove) anything with statistics.
Nov 2, 2006 | 2:17 am
#37
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Originally Posted by SAT Lawyer
Remember that increasing the number of engines increases the statistical likelihood of one engine failing. Moreover, it is my understanding that a dual engine failure on a four engine Boeing 747 with a passenger and cargo load of any significance would not permit the aircraft to retain its altitude.
Nov 2, 2006 | 3:19 am
#38
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Originally Posted by Braniff
Statistically, that would make it dangerous to fly one now.
If Jane and Joe have a 50% chance of having a girl versus a boy, and they already have 3 girls, what's their chance of having another girl? 50%.
Nov 2, 2006 | 3:38 am
#39
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Reminds me of the (probably apocryphal) conversation with one of the flight engineers for a major airline, who when asked "Why do you always fly on aeroplanes with four engines?", replied "Because they don't make them with six".
Nov 2, 2006 | 4:14 am
#40
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Personally, I think the 4 vs. 2 thing is an obsolete debate. If this were 1950 and we were talking about twin-engined DC-3's vs. quad-engined Lockheed Constellations, then it would be a different story. After all, the Constellations were colloquially known as "the finest three-engined airliners out there" due to being prone to engine failures, but this was nothing unique for airliners of the time. Piston-engined aircraft of that era were, in general, universally prone to engine failures.
But it isn't the 1950s anymore - for that matter, it isn't even the 70s and 80s anymore. With the advent of quiet, efficient, and reliable high-bypass turbofans, there is really no need for concern about the chance of total power loss mid-flight due to independent mechanical issues. And I'm amazed that no one has pointed out yet that maybe, possibly, just a hunch...could it be that the reason the 777 hasn't had a single accident in over a decade of service is the result of its [safety-oriented] design, rather than a statistical anomaly?
Nowadays, I think the main concern people should have is with hydraulics. I would much rather be on the new and improved "glider" version of the 777 than on a 777 with a total hydraulic failure. Here's an analogy. You are driving down a winding mountain road, on a downward grade. Your engine blows. You eventually have to find a pull-off, but you have some time to do it because you are headed downhill for quite a ways yet, and you are in no way in any danger because you can still steer the car and brake the car. Now let's say I let you keep your engine, but instead you lose your brakes and your steering. You are staring down a hairpin turn 1/4 mile ahead.
Which would you rather have - the engine or the directional controls?
But it isn't the 1950s anymore - for that matter, it isn't even the 70s and 80s anymore. With the advent of quiet, efficient, and reliable high-bypass turbofans, there is really no need for concern about the chance of total power loss mid-flight due to independent mechanical issues. And I'm amazed that no one has pointed out yet that maybe, possibly, just a hunch...could it be that the reason the 777 hasn't had a single accident in over a decade of service is the result of its [safety-oriented] design, rather than a statistical anomaly?
Nowadays, I think the main concern people should have is with hydraulics. I would much rather be on the new and improved "glider" version of the 777 than on a 777 with a total hydraulic failure. Here's an analogy. You are driving down a winding mountain road, on a downward grade. Your engine blows. You eventually have to find a pull-off, but you have some time to do it because you are headed downhill for quite a ways yet, and you are in no way in any danger because you can still steer the car and brake the car. Now let's say I let you keep your engine, but instead you lose your brakes and your steering. You are staring down a hairpin turn 1/4 mile ahead.
Which would you rather have - the engine or the directional controls?
Nov 2, 2006 | 5:12 am
#41
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Originally Posted by globetrekker84
Here's a little bit of reading that you might find enlightening:
4 March 2001; United Air Lines 767; near Kona, HI: While early reports indicated that this 767 had a complete loss of power in both engines, the analysis of the flight data recorder by the NTSB does not support this conclusion. According to early FAA and media reports, United Flight 42 took off from Kahului on the Hawaiian island of Maui on a flight to Los Angeles and experienced a dual-engine shutdown about 70 miles (112 km) into the flight, followed by an in-flight restart and a diversion to the Kona airport. Later analysis of the flight data recorder by the NTSB showed that both engines had a reduction of power to below idle, but did not show any evidence of a complete loss of power in either engine. However, there was roughly a 30-second gap in the data during the time when the engines were operating at reduced power. The aircraft, registration number N666UA, has since been returned to service.
Other 767 aircraft have experienced dual engine shutdowns on at least five other occasions:
23 July 1983; Air Canada 767; near Gimli, Manitoba: The aircraft ran out of fuel after the crew miscalculated the weight of fuel on board. The aircraft made an emergency landing on an abandoned airfield. There were no serious injuries.
19 August 1983; United Air Lines 767-200; near Denver, CO: Fuel contamination led to a dual-engine shutdown at about 41,000 feet. The crew restarted the engines at about 15,000 feet.
31 March 1986; United Air Lines 767-200; San Francisco, CA: The engines were inadvertently deactivated the engines during climb at about 3,000 feet. The crew was able to restart the engines and returned to the departure airport.
30 June 1987; Delta Air Lines 767-200; Los Angeles, CA: The engines were inadvertently shut off during climb at about 2,000 feet. The crew was able to restart the engines at about 500 feet and continued to their original destination of Cincinnati.
23 November 1996; Ethiopian Airlines 767-200ER; near Moroni, Comoros Islands: The aircraft was on a flight from Ethiopia to Kenya when it was hijacked. The hijackers refused to allow the aircraft to refuel, leading to a dual engine shutdown due to fuel exhaustion. Ten of the 12 crew members and 117 of the 160 passengers were killed during a subsequent ditching. The three hijackers apparently died.
4 March 2001; United Air Lines 767; near Kona, HI: While early reports indicated that this 767 had a complete loss of power in both engines, the analysis of the flight data recorder by the NTSB does not support this conclusion. According to early FAA and media reports, United Flight 42 took off from Kahului on the Hawaiian island of Maui on a flight to Los Angeles and experienced a dual-engine shutdown about 70 miles (112 km) into the flight, followed by an in-flight restart and a diversion to the Kona airport. Later analysis of the flight data recorder by the NTSB showed that both engines had a reduction of power to below idle, but did not show any evidence of a complete loss of power in either engine. However, there was roughly a 30-second gap in the data during the time when the engines were operating at reduced power. The aircraft, registration number N666UA, has since been returned to service.
Other 767 aircraft have experienced dual engine shutdowns on at least five other occasions:
23 July 1983; Air Canada 767; near Gimli, Manitoba: The aircraft ran out of fuel after the crew miscalculated the weight of fuel on board. The aircraft made an emergency landing on an abandoned airfield. There were no serious injuries.
19 August 1983; United Air Lines 767-200; near Denver, CO: Fuel contamination led to a dual-engine shutdown at about 41,000 feet. The crew restarted the engines at about 15,000 feet.
31 March 1986; United Air Lines 767-200; San Francisco, CA: The engines were inadvertently deactivated the engines during climb at about 3,000 feet. The crew was able to restart the engines and returned to the departure airport.
30 June 1987; Delta Air Lines 767-200; Los Angeles, CA: The engines were inadvertently shut off during climb at about 2,000 feet. The crew was able to restart the engines at about 500 feet and continued to their original destination of Cincinnati.
23 November 1996; Ethiopian Airlines 767-200ER; near Moroni, Comoros Islands: The aircraft was on a flight from Ethiopia to Kenya when it was hijacked. The hijackers refused to allow the aircraft to refuel, leading to a dual engine shutdown due to fuel exhaustion. Ten of the 12 crew members and 117 of the 160 passengers were killed during a subsequent ditching. The three hijackers apparently died.
The simple fact of the matter is, is that any ETOPS certified twin engine is every bit as safe as any four engined bird. To my knowledge, no ETOPS certified twin engine has ever crashed due to both engines failing from separate causes.
Nov 2, 2006 | 9:13 am
#43
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Originally Posted by Jenbel
However, a 747 with one engine lost can continue onto its destination safely (depending on cause of loss - if it's one of the events where engine loss is independent of having already lost an engine ) - so it's statistically more likely that you'll have to divert in a 777 if you lose an engine, since if they lose an engine, unless they are close to home, they're looking for someplace to land for a diversion to get the problem fixed. So the OP may be irrational from a safety case point of view, but not from an inconvenience point of view
Most long haul flights are never cleared to their final destination becuase they would not have enough fuel reserves to do so. Throughout the flight they are constantly updating their distance/fuel reserve ratio and most of the time they evenntualy get clearance to their scheduled destination.
The 2/4 engine debate is not logical but emotional. Ask yourself this question. If you are 1/2 way across the Pacific and one engine goes out, would your rather be on a 777 or 747?
Nov 2, 2006 | 9:44 am
#44
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Originally Posted by Tango
The 2/4 engine debate is not logical but emotional. Ask yourself this question. If you are 1/2 way across the Pacific and one engine goes out, would your rather be on a 777 or 747?
BTW: I was told by a colleague that the 757 had the most "over-powered" engines needed for a plane its size - because it was I suppose the first in this area. He said that a one engine 757 was better than a 3-enginge DC-8.
Nov 2, 2006 | 9:51 am
#45
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Originally Posted by Jenbel
However, a 747 with one engine lost can continue onto its destination safely (depending on cause of loss - if it's one of the events where engine loss is independent of having already lost an engine ) - so it's statistically more likely that you'll have to divert in a 777 if you lose an engine, since if they lose an engine, unless they are close to home, they're looking for someplace to land for a diversion to get the problem fixed.
More fundamentally, the statistical likelihood of an engine failure causing a delay-inducing diversion on any modern jet is so rare that it probably shouldn't even factor into any equation from a delay standpoint, especially when considering the infinitely greater chances of being delayed or even diverted for other aggregate reasons such as weather, security, other mechanical problems, etc.