"A spastic thrust reverser canal taped onto the airplane" was the irreverent description onward the Nov."A spastic thrust reverser canal taped onto the airplane" was the irreverent description onward the Nov. 5 Don Imus radio talk indicate of the Egyptair Flight 990 tragedy involving a Boeing [BA] B767-300ER The fatal in-flight deployment of a thrust reverser upon a Lauda Air 767 in 1991 points darkly in this direction. still in the wake of the Oct 31 crash of the Egyptair 767 an errant thrust reverser is not the and nothing else possibility. At this same preliminary stage of the investigation, three scenarios prevail: * A bomb Not united big enough to blow the airplane apart, if it were not that one capable of inflicting enough damage to edifice or systems to render the airplane uncontrollable. While innocent Egyptians were forward the airplane, there also were a considerable number of American tourists and Egyptian military officers aboard. The Egyptian sway has been the target of Islamic fundamentalists. However, no terrorist organization has claimed responsibility, and there is no confirmation that passengers upon the previous flight from looks Angeles debarked without proper accounting. * An uncontained engine failure. Worldwide reporting is incomplete, on the other hand the industry may be experiencing uncontained engine failures at an average rate of single a month. As John Goglia of the National Transportation Safety Board observ at a hearing onward uncontained engine failures last year, "This whole point in dispute of rotating titanium parts (blowing apart) is not that rare." (see ASW, Jan. 19 1998) As Contributing Editor Rudy Kapustin said, "We've been extremely lucky" That good fortune may have run out onward Egyptair Flight 990. * An in-flight deployment or failure of the thrust reverser It happened with fatal weight on the Lauda Air 767 which broke apart in flight and crashed in a alien area of Thailand. This is a known case, as the cockpit voice recorder captured the first officer's remark, "Ah, reverser's deployed" posterior testing revealed that the band had about 4-6 seconds to react if there was any room for expectation of recovering the airplane (the "startle effect" alone could devour much of this time). Egyptair superficially anticipates like a replay of the Lauda Air crash: rapid onset, no distress call (pilots too busy), electrical orders functioning as the airplane plummet until the radar target broke up (separated wing fluttering down?). As in the Lauda Air crash, where a reverser moot point had plagued the airplane for weeks, the Egyptair airplane experienced a reverser enigma before its final flight. In this case, the left reverser was fasteninged in place as a precautionary measure. In addition, Egyptair reportedly had incorporated all the fixes mandated from various airworthiness directives since the Lauda Air disaster, including an additional mechanical lock-up improved protection from electrical shorts and other features. Although the management is complex, if locked fitly the reverser could not display according to sources. No doubt the mechanics will be interviewed. A Notice of Propos Rulemaking (NPRM) issued generation 9 by the Federal Aviation Administration (FAA) concerning de-activation pins in succession 767 reversers noted several instances where thrust reverser had been improperly deactivated (See Docket No. 99-NM-114-AD). Nor can a reverser failure onward the remaining engine be discounted. Another Egyptair 767 experienced a partial reverser deployment in 1997 or 1998 (we have conflicting reports), in which a piece blew opposite the airplane. A heavy chunk of metal flying not on at 500 miles per hour would be a lethal weapon, and in that earlier case the airframe was damaged significantly. This affair among others, prompted the FAA to issue another 767-related NPRM Oct 13 calling for inspection and replacement of the auxiliary track assembly of 747-400 and 767-200/300 thrust reverser notes are due Dec. 3. The NPRM (No. 99-NM-208-AD) contains a chilling description of the dependence of cause and effects if the fix is not incorporated: "This condition, if not corrected...could lead to separation of a portion of the thrust reverser from the airplane during flight, possible impact of separated portions onward airplane structure, and consequent rapid decompression of the airplane, reduc controllability of the airplane, or reduc structural integrity of the fuselage." COPYRIGHT 1999 Phillips Publishing International, Inc. |
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