Well, I guess I have few, if any, readers.
Perhaps that should be a viewed as a good thing. I do not know. This day is less and less difficult for me.
Showing posts with label Aviation Safety. Show all posts
Showing posts with label Aviation Safety. Show all posts
Wednesday, September 11, 2013
Saturday, April 16, 2011
AF447 Search: Phase 5.
The FDR was found but only the chasis was located the Data Memory Module was not attached and is thought to have separated at impact. There are some other crashes wherein this separation has taken place. 04/27/11.
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The final phase of the search for the "black boxes" will be getting underway. The Alucia considered its mission complete and departed the area on April 9th. Any delay in getting the successor search vessel on scene was due to the high level of breaks in submarine cables after recent seismic activity.
The debris field is very close to the Last Known Position despite all the earlier reliance on mathematical modeling of winds and currents.
The tail section has been located. It is thought that this presently contains the FDR and CVR that would normally be found there. Recovery of the black boxes is highly probable, recovery of information from them is less certain but there is a generally high expectation that data will be recovered. Its not yet known just why the ultrasonic pingers were not detected during earlier searches.
So it becomes the usual: wait and see.
Addendum: I've been informed that the initial attempt will be tomorrow April 22nd. BEA representative is aboard even a psychologist to deal with ships crew who have difficulties dealing with the images.
..................................................
The final phase of the search for the "black boxes" will be getting underway. The Alucia considered its mission complete and departed the area on April 9th. Any delay in getting the successor search vessel on scene was due to the high level of breaks in submarine cables after recent seismic activity.
The debris field is very close to the Last Known Position despite all the earlier reliance on mathematical modeling of winds and currents.
The tail section has been located. It is thought that this presently contains the FDR and CVR that would normally be found there. Recovery of the black boxes is highly probable, recovery of information from them is less certain but there is a generally high expectation that data will be recovered. Its not yet known just why the ultrasonic pingers were not detected during earlier searches.
So it becomes the usual: wait and see.
Addendum: I've been informed that the initial attempt will be tomorrow April 22nd. BEA representative is aboard even a psychologist to deal with ships crew who have difficulties dealing with the images.
Tuesday, April 12, 2011
AF447 and the One Legged Stool
I have long been a believer in the one-legged stool theory of aviation safety. Now, I know have very few readers but since some are not in the USA let me set forth with some particularity what a one-legged stool is. Most stools have three legs and are therefore quite stable when someone sits on them. A stool with one leg allows a person to sit on it and rest just as much but does require that he remain alert. Drifting off to sleep on a three legged stool can be easy. Drifting off to sleep while on a one legged stool is just as simple but has obvious consequences: you fall and that wakes you up.
One consequence of the ultra reliability of any electrical system is that monitoring it becomes so very boring. The aircraft systems are reliable. If something fails, there is a primary backup, if that fails there is a secondary backup, etc. It is so very boring. The Fly By Wire takes this even one step further and declares that the computers are so reliable that they should even be able to override pilot input since pilots are less reliable. Only in Alternate Law Mode does the computer surrender control of the airplane to the pilot and even that is done piecemeal with only certain systems surrendered to pilot control during the various Alternate Law modes.
But what about the Pilot's mode? Pilots have various modes too. Alert, drowsy, asleep, "in the loop", "out of the loop", etc. Qantas used to force pilots to work out a position report using pen and paper rather than simply pressing a button. This would keep the pilots mentally in the loop should trouble occur. We all know that on long flights there are a variety of breaks some of which are mandatory and some of which are optional.
Physical presence on the flight deck is one thing. Mental presence is another. A pilot who is sleeping in the cockpit or merely dozing there requires some time to get back into the loop.
Some have alleged that failure to deviate around weather indicates a dozing flight crew. All we can really say is that we have no indication that the pilots were in their seats and alert. We have some indications that fatigue may have overcome a sole occupant of the cockpit. While we can think that a pilot would not nap as the plane was penetrating the convergence zone it is possible and he might have asked to be roused and the pilot who was to have him awakened fell asleep.
Dealing with suddenly being dumped into Alternate Law Mode is difficult when the pilot is awake and fully aware of his situation. If a stall developed we all wonder why but mostly we wonder why was there no reaction to it. After all, by the third lesson student pilots are practicing stalls and having it drummed into them to lower the nose instantly and add power instantly. Nothing about that changes as one progresses from student pilot in a Cessna 172 to the left-seat of a multi-engined airliner. What changes is the excitement. A student pilot on his third lesson is "in the loop". He has full situational awareness. The professional pilot in an airliner has thousands of hours of sitting there punching buttons into a computer that does the flying. Its boring. We need to bring back that one-legged stool. Keep the pilots from getting complacent.
We all wonder how the airframe could become involved in a deep stall but the question that also must be addressed is how did it all begin. If it takes too long to wake up and gain situational awareness, a brief nap can be fatal. Airline pilots really do not practice stalls. They practice approaches to stalls. Once the airspeed deteriorated and a stall started to develop action can be taken. Once a stall is fully developed and the plane is in a deep stall wherein control surfaces are functionally ineffective there is far less that can be done and the pilot is in unknown territory. It is possible the pilot woke up to a nightmare. Often an instructor will have a student practice suddenly being required to select an emergency landing zone and make the approach to a landing in some pasture rather than on an airport runway. The practice usually ends just above the farmer's field but a good instructor will sometimes actually have a student make such a landing. A recently awakened pilot might not have been able to cope with a deep stall because he had only been given simulator time for an approach to a stall. There is no Emergency Checklist for a deep stall. You either know what to do or you don't. It either works or it doesn't. There is no time to do aught but act. If there was a double flame-out (doubtful) differential thrust could not be used.
One consequence of the ultra reliability of any electrical system is that monitoring it becomes so very boring. The aircraft systems are reliable. If something fails, there is a primary backup, if that fails there is a secondary backup, etc. It is so very boring. The Fly By Wire takes this even one step further and declares that the computers are so reliable that they should even be able to override pilot input since pilots are less reliable. Only in Alternate Law Mode does the computer surrender control of the airplane to the pilot and even that is done piecemeal with only certain systems surrendered to pilot control during the various Alternate Law modes.
But what about the Pilot's mode? Pilots have various modes too. Alert, drowsy, asleep, "in the loop", "out of the loop", etc. Qantas used to force pilots to work out a position report using pen and paper rather than simply pressing a button. This would keep the pilots mentally in the loop should trouble occur. We all know that on long flights there are a variety of breaks some of which are mandatory and some of which are optional.
Physical presence on the flight deck is one thing. Mental presence is another. A pilot who is sleeping in the cockpit or merely dozing there requires some time to get back into the loop.
Some have alleged that failure to deviate around weather indicates a dozing flight crew. All we can really say is that we have no indication that the pilots were in their seats and alert. We have some indications that fatigue may have overcome a sole occupant of the cockpit. While we can think that a pilot would not nap as the plane was penetrating the convergence zone it is possible and he might have asked to be roused and the pilot who was to have him awakened fell asleep.
Dealing with suddenly being dumped into Alternate Law Mode is difficult when the pilot is awake and fully aware of his situation. If a stall developed we all wonder why but mostly we wonder why was there no reaction to it. After all, by the third lesson student pilots are practicing stalls and having it drummed into them to lower the nose instantly and add power instantly. Nothing about that changes as one progresses from student pilot in a Cessna 172 to the left-seat of a multi-engined airliner. What changes is the excitement. A student pilot on his third lesson is "in the loop". He has full situational awareness. The professional pilot in an airliner has thousands of hours of sitting there punching buttons into a computer that does the flying. Its boring. We need to bring back that one-legged stool. Keep the pilots from getting complacent.
We all wonder how the airframe could become involved in a deep stall but the question that also must be addressed is how did it all begin. If it takes too long to wake up and gain situational awareness, a brief nap can be fatal. Airline pilots really do not practice stalls. They practice approaches to stalls. Once the airspeed deteriorated and a stall started to develop action can be taken. Once a stall is fully developed and the plane is in a deep stall wherein control surfaces are functionally ineffective there is far less that can be done and the pilot is in unknown territory. It is possible the pilot woke up to a nightmare. Often an instructor will have a student practice suddenly being required to select an emergency landing zone and make the approach to a landing in some pasture rather than on an airport runway. The practice usually ends just above the farmer's field but a good instructor will sometimes actually have a student make such a landing. A recently awakened pilot might not have been able to cope with a deep stall because he had only been given simulator time for an approach to a stall. There is no Emergency Checklist for a deep stall. You either know what to do or you don't. It either works or it doesn't. There is no time to do aught but act. If there was a double flame-out (doubtful) differential thrust could not be used.
Tuesday, September 7, 2010
Enough on those SpanAir Trojan headlines!!
When will it ever stop? All these misleading headlines and in many cases totally misleading stories.
The SpanAir crash at Madrid was not in any way caused by a computer that had trojan horse software on it. The computer at the airlines headquarters which managed repair scheduling was later found to be laden with trojan malware. Its not a computer that was onboard the aircraft or had anything to do with the operation of the flight.
SpanAir flight from Madrid to Las Palmas in late August of 2008 crashed on takeoff because the crew failed to set the slats for takeoff, an absolutely critical procedure that was called out in the checklist but not actually performed. The automatic warning systems concerning the flaps and slats settings failed to sound an alarm because they are not supposed to sound when the plane is flying at high altitude. The alarm systems that did sound prior to the takeoff dealt with a pressure sensing system that is only supposed to sound at high altitude.
Physically that plane was on the ground. Electronically that plane "thought" it was already at high altitude. The pilots were not mentally there at all, but the plane did not crash because of any memory-choking malware on a maintenance-scheduling computer at SpanAir's headquarters! Why can't editors and re-write men get that straight?
On-Edit: Please note that the above rant about unprofessional journalism standards relates to the mis-reporting of the malware infected computer at SpanAir's headquarters as having had some effect on the crash.
For those interested in the crash:
It was, as they all are, pilot error. Errors that would be absurd for even a student pilot to have made.
The crew appear to have misinterpreted the stall warning as a fire warning. Well, each is serious perhaps but a stall warning is a well known sound and the remotest possibility of a stall takes precedence over any other sort of sensory input. The misinterpretation robbed the crew of a few moments of recovery time. Well, they had precious few moments to begin with and would have been unlikely to have recovered anyway. One would not expect such a lackadaisical crew to have performed a low level stall recovery correctly.
The crew failed to realize that if an alarm had been sounding an hour previously that only sounds when the plane is at high altitude then that meant they were on notice inquiry to investigate the "weight on nosewheel" switch. Yes, switch, not relay! Its the switch that is most likely to fail. Its the switch that is relatively exposed to the elements and debris accumulation. Just because the plane was obviously on the ground does not mean the various avionics systems knew that!
With a failed "weight on nosewheel" switch, the utterly critical alarm for "Idiotic Pilots Trying To Take-Off Without Slats" is automatically disabled. So there was no alarm for the one absolutely critical take-off setting on that plane! The lack of an electronic alarm however had absolutely nothing to do with the crew's failure to properly set the slats and properly check the slat setting in accordance with the checklist procedures.
The SpanAir crash at Madrid was not in any way caused by a computer that had trojan horse software on it. The computer at the airlines headquarters which managed repair scheduling was later found to be laden with trojan malware. Its not a computer that was onboard the aircraft or had anything to do with the operation of the flight.
SpanAir flight from Madrid to Las Palmas in late August of 2008 crashed on takeoff because the crew failed to set the slats for takeoff, an absolutely critical procedure that was called out in the checklist but not actually performed. The automatic warning systems concerning the flaps and slats settings failed to sound an alarm because they are not supposed to sound when the plane is flying at high altitude. The alarm systems that did sound prior to the takeoff dealt with a pressure sensing system that is only supposed to sound at high altitude.
Physically that plane was on the ground. Electronically that plane "thought" it was already at high altitude. The pilots were not mentally there at all, but the plane did not crash because of any memory-choking malware on a maintenance-scheduling computer at SpanAir's headquarters! Why can't editors and re-write men get that straight?
On-Edit: Please note that the above rant about unprofessional journalism standards relates to the mis-reporting of the malware infected computer at SpanAir's headquarters as having had some effect on the crash.
For those interested in the crash:
It was, as they all are, pilot error. Errors that would be absurd for even a student pilot to have made.
The crew appear to have misinterpreted the stall warning as a fire warning. Well, each is serious perhaps but a stall warning is a well known sound and the remotest possibility of a stall takes precedence over any other sort of sensory input. The misinterpretation robbed the crew of a few moments of recovery time. Well, they had precious few moments to begin with and would have been unlikely to have recovered anyway. One would not expect such a lackadaisical crew to have performed a low level stall recovery correctly.
The crew failed to realize that if an alarm had been sounding an hour previously that only sounds when the plane is at high altitude then that meant they were on notice inquiry to investigate the "weight on nosewheel" switch. Yes, switch, not relay! Its the switch that is most likely to fail. Its the switch that is relatively exposed to the elements and debris accumulation. Just because the plane was obviously on the ground does not mean the various avionics systems knew that!
With a failed "weight on nosewheel" switch, the utterly critical alarm for "Idiotic Pilots Trying To Take-Off Without Slats" is automatically disabled. So there was no alarm for the one absolutely critical take-off setting on that plane! The lack of an electronic alarm however had absolutely nothing to do with the crew's failure to properly set the slats and properly check the slat setting in accordance with the checklist procedures.
Friday, September 3, 2010
25 year old Ph D candidate killed in glider.
A 25 year old archeology student died on impact after her glider's wings suffered a catastrophic separation at one thousand feet during a university glider competition. Such gliders are normally trailered to and assembled at the site. The young lady successfully completed a test flight just prior to the fatal flight. Her boyfriend who witnessed the accident saw nothing amiss in the configuration or operation of the aircraft prior to the abrupt separation of the wings from the fuselage. The young lady was known to be active in white water rafting and gliding and was known as a competent and experienced glider pilot.
No cause of the wing separation has been determined. It is expected that the British Air Ministry will delegate the responsibility for the investigation to the on-site university officials who were conducting the Inter University Gliding Competition. The glider design first appeared in the early 1960s. The wood glue used in this particular glider is unknown. Apparently some of the earlier casien based glues are subject to deterioration due to fungal growth. Later gliders are said to use plastic adhesives that are stronger than the wood to which they bond.
I would have been interested in seeing her PhD dissertation published since the topic was trace elements in soil and cancer distribution. I of course have my own opinions on the subject but am more interested in linking barium content of drinking water to later diagnoses of Multiple Sclerosis. Mainly its a more prompt though less specific diagnosis since cancers tend to appear later in life with the much debated "aging causes cancer" and "cancer causes aging" controversy still unresolved.
ADDENDUM: The official cause of the fatal accident was the failure of the lower bevel bolt to be installed properly. It is impossible for the pilot to inspect such bolts or the manner in which they have been inserted. The glider pilot had ten years of experience and was president of her collegiate gliding club. Her boyfriend who had the misfortune to have to watch her rapid and uncontrollable near vertical descent from approximately 1,000 feet was an experienced glider instructor. The accident was of course totally unsurvivable even if the lower but less reliable estimate of 600 feet is assumed.
I do so hope her unfinished PhD work on the geographic distribution of trace elements in the soil and the pattern of cancer diagnoses gets published. I remain particularly interested in barium distribution rates and the subsequent diagnosis of Multiple Sclerosis.
No cause of the wing separation has been determined. It is expected that the British Air Ministry will delegate the responsibility for the investigation to the on-site university officials who were conducting the Inter University Gliding Competition. The glider design first appeared in the early 1960s. The wood glue used in this particular glider is unknown. Apparently some of the earlier casien based glues are subject to deterioration due to fungal growth. Later gliders are said to use plastic adhesives that are stronger than the wood to which they bond.
I would have been interested in seeing her PhD dissertation published since the topic was trace elements in soil and cancer distribution. I of course have my own opinions on the subject but am more interested in linking barium content of drinking water to later diagnoses of Multiple Sclerosis. Mainly its a more prompt though less specific diagnosis since cancers tend to appear later in life with the much debated "aging causes cancer" and "cancer causes aging" controversy still unresolved.
ADDENDUM: The official cause of the fatal accident was the failure of the lower bevel bolt to be installed properly. It is impossible for the pilot to inspect such bolts or the manner in which they have been inserted. The glider pilot had ten years of experience and was president of her collegiate gliding club. Her boyfriend who had the misfortune to have to watch her rapid and uncontrollable near vertical descent from approximately 1,000 feet was an experienced glider instructor. The accident was of course totally unsurvivable even if the lower but less reliable estimate of 600 feet is assumed.
I do so hope her unfinished PhD work on the geographic distribution of trace elements in the soil and the pattern of cancer diagnoses gets published. I remain particularly interested in barium distribution rates and the subsequent diagnosis of Multiple Sclerosis.
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