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Politics : Foreign Affairs Discussion Group -- Ignore unavailable to you. Want to Upgrade?

To: maceng2 who wrote (10417)	11/15/2001 5:41:07 AM
From: maceng2	Respond to of 281500

"turbulence" and rudder reversal Been quietly fuming here. Trouble is my crapola slow connection cannot pull up the appropriate links here (getting BB). I do know this for sure (saw the TV documentary <ggg> but the data will be out there) Linked data below says it all though (a)There was a long straggling investigation about certain airplanes falling out the sky for no apparent reason. It was put down to "turbulence" (b)There was a theory of "rudder reversal" put forward. No hard evidence, experts were able to advance other ideas that fitted the data along the lines of "pilot error". More on that of course -g- (c) British Airways has a more extensive data recording system then just the "black box". Lot's and lots of data recorded during each flight. (d) A BA 747 (not the Boeing model with crash problem)experienced control surface reversal during takeoff and the extensive recording system logged it. (e) Improvements were made, and now pilots also know what to do if it happens. This came up from my search... ========================================================== NTSB RELEASES FINDINGS IN BOEING 737 RUDDER MISHAPS... Despite a lack of hard physical evidence, the NTSB said last week that uncommanded rudder movement was the probable cause for the fatal crashes of United Flight 585 in 1991 and USAir Flight 427 in 1994. According to its findings, an extremely rare malfunction in a hydraulic valve could cause the rudder to move in a direction opposite that commanded by the pilot. The board recommended that all existing and future 737s have a "reliably redundant" system. ...RECOMMENDS ADDITIONAL PILOT PROCEDURES TRAINING... The board also said that pilots would be more likely to successfully recover from an uncommanded rudder reversal if they had better training. In investigating the USAir crash, engineers determined that 737 approach speeds are slow enough for the rudder to overpower the ailerons in the roll axis. The board said that 737 flight crewmembers should lower the nose if a rudder malfunctions and accelerate to allow ailerons and spoilers to overpower the rudder. avweb.com OTHER TAILS FROM BOEING: TESTING THE 737 RUDDER SYSTEM Strange and unpleasant things have been known to happen to 737s in flight and nobody knows why. An expert panel set up by the FAA will be hunting for clues by trying to mimic the aerodynamic situations involved in both the July 1992 crash of a United 737-200 as it approached Colorado Springs, Colo., and the loss a USAir 737 in September 1994 near Pittsburgh, Pa. Boeing's own tests of the rudder system assemblies have already found that extreme temperature differentials in hydraulic fluid and servo valve assemblies can cause rudder reversal. Until an answer is found, many of the world's 737 operators are flying the jets at faster-than-normal speeds to insure the other control surfaces can overpower the rudder during critical phases of flight. avweb.com

To: maceng2 who wrote (10417)	11/15/2001 6:20:33 PM
From: maceng2	Read Replies (2) \| Respond to of 281500

Queens jet crash investigators say tail fin broke free first [note from PB.. the tail fell off, then the engines fell off, and we are informed the pilots don't have a rear view mirror. OK, so where do we go from here? Anyone with any expertise have some suggestions?] The pilots on American Flight 587 probably didn't know the tail had broken off, a federal investigator says. Investigators are almost certain the 27-foot tail was the first part to break off the Airbus A300. The pilots did not have a rearview mirror and so had no way of knowing the jet had lost a tail. "They don't have a rearview mirror," George Black Jr, of the National Transportation Safety Board. "They have no idea they've lost a tail." Both engines also fell off as the plane went down shortly after takeoff from John F Kennedy Airport, killing all 260 people aboard and five more on the ground in the residential neighbourhood. Investigators have not determined the cause of the crash but say all signs point to an equipment problem rather than a criminal act. Mr Black says the tail, which was found virtually undamaged, "doesn't appear to have been sabotaged in any way". In Washington, the Federal Aviation Administration is preparing to order inspections of Airbus A300s, focusing on the tail. The order would cover 90 of the European-built planes used by three US airlines - American, FedEx and United Parcel Service. American has already agreed to do voluntary inspections of its 34 remaining A300s. "We understand that American Airlines is inspecting their fleet as a very precautionary measure," said a spokeswoman for Airbus in Toulouse, France. "We do not yet know what went wrong." ananova.com