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#111
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![]() David CL Francis wrote: On Thu, 28 Oct 2004 at 08:50:15 in message , Sylvia Else wrote: I'm amazed that the crew apparently thought it reasonable to resume normal operation after a descent like that. They should surely have realised that an immediate landing was indicated. They didn't. Their destination was Los Angeles and they diverted to the nearest they could which was San Francisco. The incident took place nearly 300nm off shore when they were NW of San Francisco. Their route would have taken them over San Francisco on the way to Los Angeles (according to my globe anyway!) Look at my response to Al on this. Yes, they landed at SF, but only after they'd initially stated their intention to proceed to LA. Their decision to divert to SF was due events subsequent to the recovery. Sylvia. |
#112
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Pilots have been taught for years that maneuvering speed means that you can put
in full control and not overstress the airplane. Never have I read that there were exceptions or qualifications to that definition, that is until now. Funny thing about this, apparantly Airbus recommended that in a procedure to lower the landing gear using the backup system they suggested yawing the airplane back and forth to help latch the gear down. Unless there is a way to do this without pushing the rudder back and forth doesn't this seem to invite a Va problem? Where were the Va experts when this procedure was written? |
#113
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Ralph Nesbitt wrote:
programmed into the computer. The only "Computer" I know of that even comes close to dealing with UNK/UNK (unknown/unknown) has 1 mouth, 2 legs, 2 arms, 2 eyes, 2 ears, & when it gets into allows A/C tog get into situations that can't be recovered from is known to emphasize the impossibility of recovering from the situation with a emphatic"OH ****". However, the flying skidoo accident at Fredericton was purely pilot induced. It is in fact one perfect example of FBW's advantages. Pilot's workload was too much for him to handle, and he didn't have the time to monitor airspeed as well as climb angle at same time. Stalled the aircraft as a result. Had there been FBW, with the computer limiting climb rate until engines were producing sufficient thrust, would the plane still have been able to climb sufficiently to avoid trees ? Maybe, maybe not. But the odds would have been better. |
#114
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Ralph Nesbitt wrote:
Seems to me if Airbus or any other manufacturer was aware AA was training it's pilots to fly/operate its products in a manner it was not engineered to be operated the manufacturer would be responsible for saying so "LOUD & CLEAR" in a manner that could not be construed as ambiguous. In principle, probably correct. But legally, wouldn't it be the FAA that would be in charge of ensuring that AA's training adheres to both its own as well as manufacturer's standards ? Airbus says it sent letters of concern to AA. Perhaps it should have sent those letters with a CC to the FAA and let the FAA ensure AA fixes the problem. Not sure Airbus has any authority on ist customers, but FAA has authority over US airlines. |
#115
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Dave wrote:
So according to the TSB report, did the stall occour before the 1st impact (on the rny and the nose gear failing) or before the 2nd impact after climbing again? The aircraft did not touch gound before stall. The pilots decided to go around prior to touching ground, but were already going too slow to start climbing right away, but they started to climb right away and stalled. Once plane touched ground, its energy dropped below sustainable flight. It may have bounced during its snow excursion.Don't remainer that detail. But the TSB specifically stated that the plane had begun to climb and gained a tiny bit of altitude before stalling after which, that was it. |
#116
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nobody wrote:
Ralph Nesbitt wrote: Seems to me if Airbus or any other manufacturer was aware AA was training it's pilots to fly/operate its products in a manner it was not engineered to be operated the manufacturer would be responsible for saying so "LOUD & CLEAR" in a manner that could not be construed as ambiguous. In principle, probably correct. But legally, wouldn't it be the FAA that would be in charge of ensuring that AA's training adheres to both its own as well as manufacturer's standards ? Airbus says it sent letters of concern to AA. Perhaps it should have sent those letters with a CC to the FAA and let the FAA ensure AA fixes the problem. Not sure Airbus has any authority on ist customers, but FAA has authority over US airlines. In the time-honored tradition of Usenet, you two are essentially jerking each other off speculating about this when you could very simply go read the primary sources. The letter from Airbus and Boeing to American Airlines, together with AA's chief pilot's rather arrogant response, are both in the public record of the investigation and can be read right he http://www.ntsb.gov/events/2001/AA58...its/239998.pdf Among other things, you'll see that the letter was signed not only by representatives of both airlines but by an FAA employee, who also was addressed in AA's reply. Clearly the FAA was aware of the training issues. |
#117
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![]() David CL Francis wrote: On Tue, 26 Oct 2004 at 18:12:20 in message TBCfd.18911$SW3.16862@fed1read01, Jay Beckman wrote: Is that due to the crash at the Paris Airshow several years back? Many people say Paris - it wasn't Paris it was Mulhouse, in the upper Rhine Valley near the junction of the Swiss and German borders. It was only a local air show and the aircraft was an almost new A320 (it had been in service for 2 days). The Airport (if you could call it that) has one main paved runway only 1000m long plus some grass strips for gliders. Air France were invited to display an A320. It could not land there. Not only that but it was a charter flight with 130 passengers aboard - how often does that happen at the Paris Air Show I wonder? The crew were probably given an inadequate briefing on the airport. Indeed they were. The idea was to do a low slow pass in landing configuration at about 100ft. (Often done in France although the air show regulations said 170 ft.) They intended to reach the maximum allowable angle of attack in the low pass. They meant they would inhibit the 'alpha floor' limit which would automatically increase power at that point. The co-pilot was supposed to control the power. When they identified the airport they were close but they saw that the crowd seemed to be along a grass strip and not along the chosen paved runway 02. They realigned and at 100 ft deactivated the alpha floor function. They sank to only 30 ft above the strip. Nope - they were using the analogue readout barometric altimeter not the more accurate digital readout radalt ( for reasons of being easier to read whilst rapidly changing in this instance ). During the take off phase the radalt and baro altimeter somehow got 'misaligned' by 70 odd feet. Hence they thought they were flying at 100ft when it was actually 30 ft. They then suddenly realised there were trees ahead at the same height or higher than the aircraft. They then called for TO power but it was too late. Speed had reduced to 122k and the engines now at flight idle responded as they should. There was then nothing anyone or the aircraft could do. 4.5 seconds after power started increasing it began hitting the trees. Actually, increased power was called for as planned. They were indeed unaware of the trees due to the poor briefing material. Exactly how and why the engines responded as they did has been a matter of considerable debate. That version of the CFM 56 ? was subsequently altered and units in service 'upgraded' following a compressor stall incident on another early A320 at Geneva ? IIRC. That is a very much abbreviated version but I believe substantially correct. IIRC, the pilot commanded a flight attitude in the landing config that the software wouldn't allow and that led to the aircraft settling into the trees. Sorry that is wrong. And it did not settle into the trees; it flew horizontally into them at an altitude of 24 ft and then sank! This accident is very often badly reported. Although the system would not permit main flight restrictions to be exceeded the performance at those low limits was as limited as any conventional aircraft would have been. It could not climb at flight idle at 122 knots and 15 degrees nose up. That is not a surprise. The response of the engines was a surprise to the pilots. Graham |
#118
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![]() "nobody" wrote in message ... Sylvia Else wrote: There have been incidents where airliners have been stressed well beyound their design limits to recover from extreme upsets, and the passengers and crew have survived to fly another day, "design limits" is the real keyword here. And it applies to bridges as well as buildings. The empire state building was built with tons of extra strength into it because at the time, the knowledge of structural aspects of materials was not very good. So you end up with a big fat heavy building that is very strong. More recent buildings are built with much better knowledge of materials and thus are built with more exact strength, much lighter materials and much thinner structure. Similarly, modern aircraft are built with much better knowledge of material properties as well as aerodynamics. So the difference between the stated limits and the actual physical limits are far less than planes built in the 1960s. So breaking the "limits" today may in fact be far more dangerous than breaking the much less well known limits of the 1960s. Johnson's flight demonstration of a early 707 being a prime example. Modern day commercial A/C would never probably not survive, but if it did to the scrap heap it would go. Ralph Nesbitt Professional FD/CFR/ARFF Type |
#119
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![]() "nobody" wrote in message ... Ralph Nesbitt wrote: Why the FACS failed to limit flight control inputs & why the rudder limiter failed to limit rudder travel in this incident are two questions that have not been addressed. First question: A300-600 is not FBW and there is no computer interpreting pilot commands. Second question: The rudder performed as commanded and did not exceed its own travel limitations. Under normal circumstances, it would not have broken the tail. However, it was a combination of rapid complete rudder movement with side slipping of aircraft which put way too much lateral force on the tail fin which snapped off. You need a lot of rudder authority in flight if, for instance, you lose an engine and need to correct for asymetric thrust. But that doesn't give you carte blanche to play with the rudder with full left to full right rapid movements while plane in side slipping and buffeted by turbulence. The issue with the incident in question was the complete vertical stabilizer breaking off, not just the rudder fin. Ralph Nesbitt Professional FD/CFR/ARFF Type |
#120
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![]() "Corky Scott" wrote in message ... On Wed, 27 Oct 2004 03:47:24 GMT, "Dave Stadt" wrote: Simply not true. Automobiles will not turn over on flat pavement unless they hit something. It has been a law for decades. I've seen filmed demonstrations of cars flipping simply by turning. It was an expose on Jeeps. Seems dealerships were outfitting the CJ5's with oversize tires and sending them out into the world. People were flipping them doing what almost amounts to normal driving, without hitting anything or skidding. The team doing the expose outfitted one of these Jeeps with sidebars to prevent the vehical from completely rolling over, then did a series of J turns in a parking lot. At the terminex of each J turn, the Jeep dramatically lifted up and would have tipped over were it not for the sidebars. Yes, the Jeeps had a high center of gravity due to the oversize tires, and a narrow track. Otherwise it would have been much more difficult to get it to tip over. But it DID tip many times simply by turning sharply, and at a not so fast speed. Most normal streetcars are built too low to the ground, and have tires that do not develop enough traction to flip simply by turning or spinning. They require the additional assistance of hitting a curb or boulder or dropping a tire into a small ditch while sideways. SUV's are more vulnerable than run of the mill street cars due to their higher center of gravity because they are "off road vehicals" and have extra clearance for off roading, although of course they are almost never actually used as such. Corky Scott Since when did the average "Soccer Mom SUV" become an "Off Road Vehicle"? Ralph Nesbitt Professional FD/CFR/ARFF Type |
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