AAL A-300 accident
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Sorry to say fireflybob, that all of the older guys (at AA), who absolutely knew about the problems of using the rudder in a very inappropriate way, have all retired.
The young turks at AA, many trained in military fast jets, really have NO idea about large heavy sweptwing jet transport aircraft....why else do you think that AA has nearly the worst safety (hull loss) record of all the US major aircarriers?
I suppose that many of the AA guys are just too busy with one finger salutes and poor comments on the PA to really pay attention....to business.
A top to bottom audit of AA flight operations and especially upset training, by the FAA is surely in order.
The young turks at AA, many trained in military fast jets, really have NO idea about large heavy sweptwing jet transport aircraft....why else do you think that AA has nearly the worst safety (hull loss) record of all the US major aircarriers?
I suppose that many of the AA guys are just too busy with one finger salutes and poor comments on the PA to really pay attention....to business.
A top to bottom audit of AA flight operations and especially upset training, by the FAA is surely in order.
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Flight Safety,
I think the rudder system on the A300 is pretty logical.
It's the same principle as steering inputs in a car.
If I'm doing 30mph and I want to swerve to avoid an object I would move the steering wheel about 12 inches. If the same thing happens at 70mph the input would be reduced to about 4 inches
Simply put: The faster you go, the more sensitive the controls become.
Whether or not this better or worse than the Boeing system is debatable, but it is a pretty simple principle. And as long as anyone flying the aircraft kept this in mind they should not have had difficulty in controlling the amount of rudder input.
Cheers,
--
HaM
I think the rudder system on the A300 is pretty logical.
It's the same principle as steering inputs in a car.
If I'm doing 30mph and I want to swerve to avoid an object I would move the steering wheel about 12 inches. If the same thing happens at 70mph the input would be reduced to about 4 inches
Simply put: The faster you go, the more sensitive the controls become.
Whether or not this better or worse than the Boeing system is debatable, but it is a pretty simple principle. And as long as anyone flying the aircraft kept this in mind they should not have had difficulty in controlling the amount of rudder input.
Cheers,
--
HaM
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2 facts remain .....
The A300 has been in production now for 32 years (and still is), and has not got a record of any spurious failures leading to tragedy.
There have been a handful of A-300 accidents, practically all CFIT, or pilot error.
Let the record stand.
It doesn't make it immune to any failings (as any airliner) , but there are a good many high cycle examples out there which stand testament to its solid design.
A type rating would surely give you the required knowledge of the A-300's rudder properties which should of course be taken into account whilst flying the plane.
The A300 has been in production now for 32 years (and still is), and has not got a record of any spurious failures leading to tragedy.
There have been a handful of A-300 accidents, practically all CFIT, or pilot error.
Let the record stand.
It doesn't make it immune to any failings (as any airliner) , but there are a good many high cycle examples out there which stand testament to its solid design.
A type rating would surely give you the required knowledge of the A-300's rudder properties which should of course be taken into account whilst flying the plane.
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AAL A-300 accident
Flight Safety,
Reworded for better comprehension,
In fact, the co-pilot never had control of the rudder after it was struck by the 0.3 and the 0.4 G forces of the "Heavy" Boeing 747’s vortices! THESE FORCES STRIKING THE LARGE RUDDER SURFACE AREA BROADSIDE, BROKE THE LINKAGES TO THE RUDDER ACTUATORS! The rudder was then free floating, reacting to the rotating vortices striking it alternately, first on one side and then the other. This whipping action of the rudder, back and forth, was faster than any pilot would command, even if he was physically able to do so!.
Although the co-pilot used full opposite aileron to counter the steep left bank, there was no evidence of any right rudder input to assist in the recovery attempt. There was no rudder available!
Hope this clears it up.
Fraternally
Reworded for better comprehension,
In fact, the co-pilot never had control of the rudder after it was struck by the 0.3 and the 0.4 G forces of the "Heavy" Boeing 747’s vortices! THESE FORCES STRIKING THE LARGE RUDDER SURFACE AREA BROADSIDE, BROKE THE LINKAGES TO THE RUDDER ACTUATORS! The rudder was then free floating, reacting to the rotating vortices striking it alternately, first on one side and then the other. This whipping action of the rudder, back and forth, was faster than any pilot would command, even if he was physically able to do so!.
Although the co-pilot used full opposite aileron to counter the steep left bank, there was no evidence of any right rudder input to assist in the recovery attempt. There was no rudder available!
Hope this clears it up.
Fraternally
Last edited by wsherif1; 25th Feb 2004 at 01:55.
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birdbrain,
Your comment,
"Please excuse my ignorance, but, how did an A300 manage to find the wake of a 747 so soon after t/o ???"
It was there, and the co-pilot made a perfect formation join up on the center of an invisible, horizontal tornado. (the "Heavy" B 747's vortex)
Shortly after T/O ATC released AA 587 to go direct to the departure fix. AA 587's shorter turning radius, compared to the B 747, turned it inside the "Heavy's" track to the same fix. The wind direction moved the B747's vortex into AA 587's projected flight path, with the resultant intercept.
Fraternally
Your comment,
"Please excuse my ignorance, but, how did an A300 manage to find the wake of a 747 so soon after t/o ???"
It was there, and the co-pilot made a perfect formation join up on the center of an invisible, horizontal tornado. (the "Heavy" B 747's vortex)
Shortly after T/O ATC released AA 587 to go direct to the departure fix. AA 587's shorter turning radius, compared to the B 747, turned it inside the "Heavy's" track to the same fix. The wind direction moved the B747's vortex into AA 587's projected flight path, with the resultant intercept.
Fraternally
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Wsherif1, I appreciate you're rewording, but my question still stands. How could these .3G and .4G forces from a wingtip vortex against the rudder, cause complete failure of all the rudder PCA attachments?
I've tried to follow this accident, and I've read nothing from the NTSB (or other sources) indicating that the failure of the PCA attachments to the rudder, was a precipitating cause of the accident. It it were, the NTSB has been focusing on the vertical fin attachment lugs and pilot use of the rudder, in vain.
I've tried to follow this accident, and I've read nothing from the NTSB (or other sources) indicating that the failure of the PCA attachments to the rudder, was a precipitating cause of the accident. It it were, the NTSB has been focusing on the vertical fin attachment lugs and pilot use of the rudder, in vain.
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AAL A-300 accident
Flight Safety,
Your comment,
"How could these .3G and .4G forces from a wingtip vortex against the rudder, cause complete failure of all the rudder PCA attachments"
You will note that in the picture of the vertical stabilizer being hauled up from the barge that there are no linkages attached to the rudder actuators. When were they disconnected?
Nasa states that the angular forces in a rotating vortex can reach 300'/sec. These forces striking the surface area of the rudder, broadside, on one side and then the other, alternately, could cause a linkage failure. Do you really think that any pilot would kick the rudder back and forth rapidly, as recorded?
Of course when the .8G force struck the rudder it was broken into four pieces. The linkages were severed from the rudder at some point in the flight. THE CO-PILOT did not have any use of the rudder in the attempted recovery!
Your further comment.
"If it were, the NTSB has been focusing on the vertical fin attachment lugs and pilot use of the rudder, in vain."
Yes I agree.
Your comment,
"How could these .3G and .4G forces from a wingtip vortex against the rudder, cause complete failure of all the rudder PCA attachments"
You will note that in the picture of the vertical stabilizer being hauled up from the barge that there are no linkages attached to the rudder actuators. When were they disconnected?
Nasa states that the angular forces in a rotating vortex can reach 300'/sec. These forces striking the surface area of the rudder, broadside, on one side and then the other, alternately, could cause a linkage failure. Do you really think that any pilot would kick the rudder back and forth rapidly, as recorded?
Of course when the .8G force struck the rudder it was broken into four pieces. The linkages were severed from the rudder at some point in the flight. THE CO-PILOT did not have any use of the rudder in the attempted recovery!
Your further comment.
"If it were, the NTSB has been focusing on the vertical fin attachment lugs and pilot use of the rudder, in vain."
Yes I agree.
Last edited by wsherif1; 26th Feb 2004 at 14:20.
ex-Tanker
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When were they disconnected?
A good question - do you have the answer? I also think not. if the rudder broke away then the linkages would be the next to go.
As regards sensitivity, of course the rudder gets more sensitive as Q increases. This was the reason for the rudder limiter on such classics as the MD-80, where from around 17deg+- at circuit speeds, only round 2.5deg+- were available at cruise speed, depending on model.
The pilots had the reason for this explained to them during instruction on type.
The guy who designed that knew why but as with 411's pilots, the new age designers have missed out on some hard earned experience.
As regards sensitivity, of course the rudder gets more sensitive as Q increases. This was the reason for the rudder limiter on such classics as the MD-80, where from around 17deg+- at circuit speeds, only round 2.5deg+- were available at cruise speed, depending on model.
The pilots had the reason for this explained to them during instruction on type.
The guy who designed that knew why but as with 411's pilots, the new age designers have missed out on some hard earned experience.
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Come now 411A..... With as many planes as they have the chances for accident is much greater just like buying thousands of lottery tickets.
I have seen some of the most seasoned and experienced pilots in the USA that are also flight test DERs wag that damn tail like a trout going up river. Or maybe is it that Boeing's have stronger tails???
I would also think that the rudder attach linkage would be designed such that the rudder departs the airplane before it snaps the whole tail off. Plenty of airplanes been safely landed without a rudder and only tail.
I have seen some of the most seasoned and experienced pilots in the USA that are also flight test DERs wag that damn tail like a trout going up river. Or maybe is it that Boeing's have stronger tails???
I would also think that the rudder attach linkage would be designed such that the rudder departs the airplane before it snaps the whole tail off. Plenty of airplanes been safely landed without a rudder and only tail.
Last edited by 747FOCAL; 27th Feb 2004 at 01:02.
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Wsherif1, with all due respect, I just can't follow your logic.
This link is to an NTSB accident update, dated 11/20/01.
NTSB 11/20/01 update
The press release says in part:
At the time of this press release, you will note the NTSB believed that the wake encounters produced .1G lateral loads. They further state that later .3G and .4G lateral loads correspond in time with FDR recorded rudder movements.
I'm not aware that the NTSB has changed it's position regarding these facts. If they have changed their position, I'd be happy to examine the sources for this information.
Regards,
Flight Safety
This link is to an NTSB accident update, dated 11/20/01.
NTSB 11/20/01 update
The press release says in part:
Based on radar data, flight 587 took off approximately 105 seconds behind Japan Airlines flight 47, a Boeing 747. The FDR indicates that flight 587 encountered two wake vortices generated by JAL flight 47. The second wake encounter occurs about 8 seconds before the end of the FDR data. For the first few seconds after the second wake encounter, the aircraft responded to flight control inputs. Both wake encounters averaged about 0.1 G lateral (side to side) movement. During the last 8 seconds of FDR data, the plane experienced three stronger lateral movements, two to the right of 0.3 and 0.4 Gs, and then one to the left of 0.3 Gs. These lateral forces corresponded in time with rudder movements. The NTSB continues to investigate the cause of the rudder movements.
I'm not aware that the NTSB has changed it's position regarding these facts. If they have changed their position, I'd be happy to examine the sources for this information.
Regards,
Flight Safety
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AAL A-300 accident
Flight Safety,
NTSB report excerpt,
"These lateral forces corresponded in time with rudder movements. The NTSB continues to investigate the cause of the rudder movements."
These lateral forces were induced by the rotating vortices striking the aircraft structure, and the vertical stabilizer surface area, broadside. The resulting lateral motion streamlined the free floating rudder, (Disconnected or broken rudder actuator linkages from reversng .3G and .4G forces on the rudder.) inline with the direction of lateral motion.
Surely you do not believe the co-pilot, or any other pilot would kick the rudder back and forth rapidly, as recorded.
Addenda.
NTSB report excerpt,
"The FDR indicates that flight 587 encountered two wake vortices generated by JAL flight 47." Negative!
Flight 587 actually encountered first the left side of the left rotating vortex from the B-747 and then the right side, which explains the opposite direction wind shear strikes.
Fraternally,
wsherif1
NTSB report excerpt,
"These lateral forces corresponded in time with rudder movements. The NTSB continues to investigate the cause of the rudder movements."
These lateral forces were induced by the rotating vortices striking the aircraft structure, and the vertical stabilizer surface area, broadside. The resulting lateral motion streamlined the free floating rudder, (Disconnected or broken rudder actuator linkages from reversng .3G and .4G forces on the rudder.) inline with the direction of lateral motion.
Surely you do not believe the co-pilot, or any other pilot would kick the rudder back and forth rapidly, as recorded.
Addenda.
NTSB report excerpt,
"The FDR indicates that flight 587 encountered two wake vortices generated by JAL flight 47." Negative!
Flight 587 actually encountered first the left side of the left rotating vortex from the B-747 and then the right side, which explains the opposite direction wind shear strikes.
Fraternally,
wsherif1
Last edited by wsherif1; 27th Feb 2004 at 04:16.
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A300-600: 0.93
McDonnell Douglas MD-11: 0.273
Boeing 777: 0.214
Boeing 747: 0.197
Boeing 767: 0.127
McDonnell Douglas MD-11: 0.273
Boeing 777: 0.214
Boeing 747: 0.197
Boeing 767: 0.127
