Delta Airlines B777 Divert to Ascension
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Thanks to all those that replied. I always learn something new.
I think this thread makes evident that while we may think that decision rules for ETOPS/"land at the nearest suitable airport" are clear, they are far from it. What is "suitable" can be open to debate based on runways, weather, fuel, MLW and distance to the next-best "suitable" airport. This seems so complicated that it is unlikely that a comprehensive a priori decision tree can be established. In the end, the decision must rely on the circumstances of the particular incident, and the decisionmaking prowess of the flight crew and dispatchers. That's why you guys should get paid as much (or more
) than you do.
Note: I only referred to ETOPS/two-holer decisionmaking because at least it does start from some baseline rule of general applicability (land at the nearest suitable airport). As we all know from BA B747 ex-LAX, permitted decisionmaking for 3's and 4's is even more untethered from predefined rules.
I think this thread makes evident that while we may think that decision rules for ETOPS/"land at the nearest suitable airport" are clear, they are far from it. What is "suitable" can be open to debate based on runways, weather, fuel, MLW and distance to the next-best "suitable" airport. This seems so complicated that it is unlikely that a comprehensive a priori decision tree can be established. In the end, the decision must rely on the circumstances of the particular incident, and the decisionmaking prowess of the flight crew and dispatchers. That's why you guys should get paid as much (or more
) than you do.Note: I only referred to ETOPS/two-holer decisionmaking because at least it does start from some baseline rule of general applicability (land at the nearest suitable airport). As we all know from BA B747 ex-LAX, permitted decisionmaking for 3's and 4's is even more untethered from predefined rules.
Indeed the rules are different for two engine aircraft as opposed to 3 or 4. With the loss of an engine in a twin there is an immediacy to landing that is reflected in the rule of landing at the nearest suitable. It is what constitutes suitable at that time that is the matter of some consideration and thinking. One has to be VERY careful in overflying a suitable airport in that situation if one is down to a single motor. Doing so would involve a lot of explaining at the tea and biscuit time that would be sure to follow such a decision.
As far as the discussion of the evolution toward large long-range twins economics do play a significant role. Three and four engine aircraft of course do not need to comply with the absolute rigor of twin operations and thus are afforded some savings for the planning, not to mention, the expense of an actual divert. We only need to look at the cost that Delta surely must have incurred during the Ascension divert. If they had to hire out a 747F to bring in a new engine that alone would have been expensive to state the obvious. Add to that the cost of the discomfited passengers, the aircraft launched to come and get them, and that two airframes are not (at least for a couple of days) in the normal rotation of generating revenue and the one side of the balance sheet takes a bit of a hit.
I always like to remark that long-range twins share a lot in common with quantum physics. Both are predicated on probabilities and translated from the indeterminate through the language of statistics! There is a trade-off that each carrier must make for the planned routes.
I actually enjoy the finer point inherent in that trade-off. When I tour an air museum with guests I always remark, whether it be a Beech Staggerwing or the Concorde, that an aircraft is a compromise. Perhaps a wonderful and ingenious compromise, but a compromise nonetheless. The same applies for the trade-off of the twins to four motors--there is some compromise being made.
As far as being far over the Laptev Sea on a twin in the middle of winter, well...the airplane does not know (so to speak) whether it is over land or water but I sure do!
Speaking of statistics, I am still trying to grasp Boeing's position that more diverts are made for reasons other than engine failures. I can understand that, but having chatted with one of the gents who was on the 3 hour Mid-Pacific Odyssey on one engine, the statistics take on a different meaning at that time. It is often difficult for humans to overcome the counter-intuitive. In other words, sure more diverts are made for sick passengers or hydraulic failure, but the question is what happens on those few, and perhaps not so happy times, when an engine does fail? Do I really wish to be 204 minutes (or more if Boeing and the other manufacturers -prevail in this discussion) from an aerodrome? There does need to be some comfort level after all...
As far as the discussion of the evolution toward large long-range twins economics do play a significant role. Three and four engine aircraft of course do not need to comply with the absolute rigor of twin operations and thus are afforded some savings for the planning, not to mention, the expense of an actual divert. We only need to look at the cost that Delta surely must have incurred during the Ascension divert. If they had to hire out a 747F to bring in a new engine that alone would have been expensive to state the obvious. Add to that the cost of the discomfited passengers, the aircraft launched to come and get them, and that two airframes are not (at least for a couple of days) in the normal rotation of generating revenue and the one side of the balance sheet takes a bit of a hit.
I always like to remark that long-range twins share a lot in common with quantum physics. Both are predicated on probabilities and translated from the indeterminate through the language of statistics! There is a trade-off that each carrier must make for the planned routes.
I actually enjoy the finer point inherent in that trade-off. When I tour an air museum with guests I always remark, whether it be a Beech Staggerwing or the Concorde, that an aircraft is a compromise. Perhaps a wonderful and ingenious compromise, but a compromise nonetheless. The same applies for the trade-off of the twins to four motors--there is some compromise being made.
As far as being far over the Laptev Sea on a twin in the middle of winter, well...the airplane does not know (so to speak) whether it is over land or water but I sure do!
Speaking of statistics, I am still trying to grasp Boeing's position that more diverts are made for reasons other than engine failures. I can understand that, but having chatted with one of the gents who was on the 3 hour Mid-Pacific Odyssey on one engine, the statistics take on a different meaning at that time. It is often difficult for humans to overcome the counter-intuitive. In other words, sure more diverts are made for sick passengers or hydraulic failure, but the question is what happens on those few, and perhaps not so happy times, when an engine does fail? Do I really wish to be 204 minutes (or more if Boeing and the other manufacturers -prevail in this discussion) from an aerodrome? There does need to be some comfort level after all...
Last edited by Uncle Fred; 16th Jan 2013 at 00:27.
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hello roberts
Can you confirm "No approach lights"?
The lights are tech mains from the Cat Hill power station'.
Or do you mean "non-standard".
The lights are tech mains from the Cat Hill power station'.
Or do you mean "non-standard".
Last edited by enicalyth; 23rd Jan 2013 at 18:56.
As we know, the actual divert to the field is only 75% of the task. What to do is just as critical in some cases and good communication is prt and parcel of the event. Sometimes more work once one lands...anxious to see the preliminary on this one,
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published in "the-islander" website
"Wideawake Airfield was the scene in the early hours of Thursday 10 January of an emergency landing by a Delta Airlines Boeing 777 aircraft that had lost all the power to one of its two engines.
The aircraft, which was en route from Johannesburg to Atlanta declared an emergency and safely landed at 0100 hours. There were no injuries amongst the 291 passengers and crew on board.
The UK and US Bases, with Ascension Police, worked closely together to provide accommodation and meals to all 291. Delta Airlines sent a relief aircraft to pick up and take all of the passengers onto Atlanta, departing at 1900 the same day.
By coincidence, the RAF Airbridge to the Falkland Island clipped the wings of the Delta Airlines flight at 0800 resulting in a delayed departure for those going southwards while the plane was checked and found to be fit for service.
Delta Airlines sent a 747 aircraft in on Saturday 12 January with a replacement engine for their stranded aircraft to enable it to finally complete its journey to Atlanta.
Ascension Island and its military bases worked well to provide emergency assistance to the aircraft and its many passengers. Emergency requests like the one handled on 10 January are thankfully very rare indeed."
The aircraft, which was en route from Johannesburg to Atlanta declared an emergency and safely landed at 0100 hours. There were no injuries amongst the 291 passengers and crew on board.
The UK and US Bases, with Ascension Police, worked closely together to provide accommodation and meals to all 291. Delta Airlines sent a relief aircraft to pick up and take all of the passengers onto Atlanta, departing at 1900 the same day.
By coincidence, the RAF Airbridge to the Falkland Island clipped the wings of the Delta Airlines flight at 0800 resulting in a delayed departure for those going southwards while the plane was checked and found to be fit for service.
Delta Airlines sent a 747 aircraft in on Saturday 12 January with a replacement engine for their stranded aircraft to enable it to finally complete its journey to Atlanta.
Ascension Island and its military bases worked well to provide emergency assistance to the aircraft and its many passengers. Emergency requests like the one handled on 10 January are thankfully very rare indeed."
A couple of points from the article. Did not Delta have to contract out to Atlas to carry in the new engine? A Delta 747 was mentioned but they need a freighter for an engine carry. I know this is a small point and I certainly do not mean to sound pedantic, rather I just like to know how the various carriers put together their recovery plans.
The second talked about a clipping of the wing tips. On which Delta aircraft? The one that had diverted in or the one that came in to pick up the passengers? It would seem to be the former according to the time-stamp given.
Either way, one can readily see the orchestration involved in one of these diverts. To say that there is a lot involved is a definite understatement.
Now picture one of these diverts into one of the really cold fields that are used for Polar and Northern Pacific flying. Ascension has good weather, good communications, and the passengers are in safe conditions. Drop a distressed/ single engine aircraft into a place like Svalbard, Thule, or Barrow in the middle of winter and the complexity is astounding. Challenging to say the least as the cold alone is nothing short of dangerous.
The second talked about a clipping of the wing tips. On which Delta aircraft? The one that had diverted in or the one that came in to pick up the passengers? It would seem to be the former according to the time-stamp given.
Either way, one can readily see the orchestration involved in one of these diverts. To say that there is a lot involved is a definite understatement.
Now picture one of these diverts into one of the really cold fields that are used for Polar and Northern Pacific flying. Ascension has good weather, good communications, and the passengers are in safe conditions. Drop a distressed/ single engine aircraft into a place like Svalbard, Thule, or Barrow in the middle of winter and the complexity is astounding. Challenging to say the least as the cold alone is nothing short of dangerous.
Last edited by Uncle Fred; 25th Jan 2013 at 19:15.
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ding ding
It was the incoming A330 referred to as the 0800 flight [ASI keeps Zulu time] which struck the parked B777. Hence the banter between FE and myself regarding the dings and references to Damian.
If you look at http://www.the-islander.org.ac/art_10511_16_0.html you will see the "stones" celebrating 1AMW in the foreground - that is Round Hill SH 449ft with the tower visible; South Gannet Hill is further on with VORTAC ASI.
I can think of better places to park than than where DAL left it! Shurely shome mishtake. And of course in come Hi Fly and it's time for tea and biscuits. Ah well, at least it was not an oggie who did it.
You made a good point back there a bit. When crossing N23 00.0 it is customary to call Ops c/s Haven. If you pass Dakar and Conakry without assurance that the runway is clear........ not pretty.
I won't get into this and that, its not the time and place but I have views on what constitutes "suitable". I will say I'd prefer to be a wee bit closer to Accra should it have happened to me.
Lovely place. I can hear the breakers thumping on Long Beach even now.
If you look at http://www.the-islander.org.ac/art_10511_16_0.html you will see the "stones" celebrating 1AMW in the foreground - that is Round Hill SH 449ft with the tower visible; South Gannet Hill is further on with VORTAC ASI.
I can think of better places to park than than where DAL left it! Shurely shome mishtake. And of course in come Hi Fly and it's time for tea and biscuits. Ah well, at least it was not an oggie who did it.
You made a good point back there a bit. When crossing N23 00.0 it is customary to call Ops c/s Haven. If you pass Dakar and Conakry without assurance that the runway is clear........ not pretty.
I won't get into this and that, its not the time and place but I have views on what constitutes "suitable". I will say I'd prefer to be a wee bit closer to Accra should it have happened to me.
Lovely place. I can hear the breakers thumping on Long Beach even now.
