Jackscrew End Stop Probably Cause of AS 261 Crash
Iconoclast
Join Date: Sep 2000
Location: The home of Dudley Dooright-Where the lead dog is the only one that gets a change of scenery.
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Don't change anything.
Nothing needs to be changed except the attitude airlines have regarding performing maintenance in the prescribed manner instead of cutting corners. The life cycle for any element on an aircraft is predicated on the performance of the maintenance agreed upon in the maintenance-working group prior to certification and if applicable the MSG analysis. The engineers establish wear limits and that they specify that the maintenance program for any item includes periodic inspections to determine if limits are met or exceeded and lubrication where necessary.
A lot of people lost their lives because of lax management of the maintenance program and it will kill a lot of people in the future unless there is a change in attitude. It was not a design problem, and it was not Murphy’s law. It was just plain hardheadedness and stupidity.
IMHO
A lot of people lost their lives because of lax management of the maintenance program and it will kill a lot of people in the future unless there is a change in attitude. It was not a design problem, and it was not Murphy’s law. It was just plain hardheadedness and stupidity.
IMHO
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It was quite a while from the initial indications of a failure, and some to-and-fro with the company maintenance department on VHF before the loss of control. It appeared from what I read that the crew was trying to make the situation better by attempting to adjust the stab.
I would recommend that if a failure occurs, the flight crew should not attempt to fix it, or at least confine their efforts to one attempt, and concentrate on getting on the ground. Perhaps the continued effort to make the jackscrew move, in this instance, was the final straw that broke it.
During its circling, the airplane was close to a large military base, right on the coast and in plain sight, yet the effort was being made to return to LAX, flying over congested areas probably. I am sure the Navy would have offered help if asked.
Most likely the tragic outcome would have been the same no matter what the crew did in this instance, but if there is something for us to learn from this accident, it might prevent a future loss of life.
I would recommend that if a failure occurs, the flight crew should not attempt to fix it, or at least confine their efforts to one attempt, and concentrate on getting on the ground. Perhaps the continued effort to make the jackscrew move, in this instance, was the final straw that broke it.
During its circling, the airplane was close to a large military base, right on the coast and in plain sight, yet the effort was being made to return to LAX, flying over congested areas probably. I am sure the Navy would have offered help if asked.
Most likely the tragic outcome would have been the same no matter what the crew did in this instance, but if there is something for us to learn from this accident, it might prevent a future loss of life.
Join Date: Jun 2001
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Monday morning quarterbacking
I wouldn't be so quick to second guess the crew of 261. They were highly trained professionals doing the best job they could manage.
They thought they had a runaway trim--a situation they were trained for. There's no way they could've known how dire their situation was.
As for overflying suitable airports: Here you have a point. They passed San Diego and El Toro and decided to land at Los Angeles where they have a base. A total distance of 100nm. It probably took 15 mins to fly from San Diego to LA.
A very busy and tense 15 minutes. They were ordinary men doing an outstanding job.
They thought they had a runaway trim--a situation they were trained for. There's no way they could've known how dire their situation was.
As for overflying suitable airports: Here you have a point. They passed San Diego and El Toro and decided to land at Los Angeles where they have a base. A total distance of 100nm. It probably took 15 mins to fly from San Diego to LA.
A very busy and tense 15 minutes. They were ordinary men doing an outstanding job.
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HELP ! I tried the recommended ways, by the NTSB, to get the detailed FDR data beyond what little is in the docket. Does somebody know how to get the detailed FDR data just like the very good detailed data for the AA flight into Queens in Nov 2001.
HELP ! I tried the recommended ways, by the NTSB, to get the detailed FDR data beyond what little is in the docket. Does somebody know how to get the detailed FDR data just like the very good detailed data for the AA flight into Queens in Nov 2001.
Join Date: Jul 2002
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Regarding FDR data and NTSB Public Dockets.
While the AA 587 NTSB Hearing was in progress, the material available on-line at the NTSB was labeled (apparently very carefully) “Exhibits from the Public Docket”.
One of the on-line documents was
---- Quote ---
168199 Sep 30, 2002 Flight Data Recorder 10 - Flight Data Recorder Group Chairman's Solid State Flight Data Recorder Factual Report
---- End quote ---
The last words in this document were:
---- Quote ---
Enclosures:
Attachment I: Flight Data Recorder Parameter Listing Sorted By Word Location
Attachment II: Selected Flight Data Recorder Data Plotted (8 Plots Total)
Attachment III: Flight Data Recorder Data in Comma Delimited (CSV) Format Files for the
Following:
• FDR Data Plotted in Attachment II
• .GMT hours., .GMT minutes. and .GMT seconds.
---- End quote ---
However, these “Enclosures” were (and still are) not on-line.
Aviation Week and Space Technology printed one graph of FDR data in their report on the hearings one week later, and also made the graph available on-line. So the data had been released but the NTSB chose not to put it on-line.
In contrast, all the FDR data listed above as being in the “Enclosures” is on the AA 587 NTSB CD-ROM available free-of-charge from the NTSB, including all the digital data as zip-files, so the word “from” in “Exhibits from the Public Docket”, noted above, is significant.
Maybe there is a NTSB CD-ROM disc available for AS 261 with more info?
The flight reconstruction based on the AS 261 FDR traces is on-line at the NTSB site, so I have difficulty believing that the FDR data is being disputed. But I don’t know.
Cheers,
While the AA 587 NTSB Hearing was in progress, the material available on-line at the NTSB was labeled (apparently very carefully) “Exhibits from the Public Docket”.
One of the on-line documents was
---- Quote ---
168199 Sep 30, 2002 Flight Data Recorder 10 - Flight Data Recorder Group Chairman's Solid State Flight Data Recorder Factual Report
---- End quote ---
The last words in this document were:
---- Quote ---
Enclosures:
Attachment I: Flight Data Recorder Parameter Listing Sorted By Word Location
Attachment II: Selected Flight Data Recorder Data Plotted (8 Plots Total)
Attachment III: Flight Data Recorder Data in Comma Delimited (CSV) Format Files for the
Following:
• FDR Data Plotted in Attachment II
• .GMT hours., .GMT minutes. and .GMT seconds.
---- End quote ---
However, these “Enclosures” were (and still are) not on-line.
Aviation Week and Space Technology printed one graph of FDR data in their report on the hearings one week later, and also made the graph available on-line. So the data had been released but the NTSB chose not to put it on-line.
In contrast, all the FDR data listed above as being in the “Enclosures” is on the AA 587 NTSB CD-ROM available free-of-charge from the NTSB, including all the digital data as zip-files, so the word “from” in “Exhibits from the Public Docket”, noted above, is significant.
Maybe there is a NTSB CD-ROM disc available for AS 261 with more info?
The flight reconstruction based on the AS 261 FDR traces is on-line at the NTSB site, so I have difficulty believing that the FDR data is being disputed. But I don’t know.
Cheers,
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Some DFDR data may be in dispute. The DFDR can only record the parameters for the stab between its design positions. The NTSB first established from the behaviour of the plane that only the movement of the stab to an extreme aircraft nose down position, well beyond design parameters, could have cause the final plunge. They then used aerodynamic and load data to extrapolate the actual position the stab, roughly 10 degress AND or more. As this is not on the DFDR it may be open to dispute, even though there is no other scientific explanation.
Don't know if this data is in dispute specifically, but as Alaska is in deep denial about this crash anyway, it probably is.
Don't know if this data is in dispute specifically, but as Alaska is in deep denial about this crash anyway, it probably is.
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There is another factor here that also came into play in the AA 587 accident. In both incidents, circuit breakers were recycled prior to the failure. In the AA 587 incident, I believe it was the yaw damper breaker that was recycled prior to departure because of an intermittent failure during the preflight. In AS 261, the crew evidently recycled breakers that tripped during trim attempts.
I will go back to a post that I made several months ago about AA 587: resetting breakers should not be allowed until the cause of the either the circuit trip or intermittent problem is determined. Resetting breakers to either fix an intermittent problem or because there is no obvious cause of a trip is just asking for trouble. In fact, I also believe that the crew of SwissAir 111 also reset breakers prior to the loss of that flight. When will the aviation industry figure this out?????
I will go back to a post that I made several months ago about AA 587: resetting breakers should not be allowed until the cause of the either the circuit trip or intermittent problem is determined. Resetting breakers to either fix an intermittent problem or because there is no obvious cause of a trip is just asking for trouble. In fact, I also believe that the crew of SwissAir 111 also reset breakers prior to the loss of that flight. When will the aviation industry figure this out?????
