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FAA Cites Pylon Failure in El Al Crash; Passenger Jets May Also Be At Risk

October 24, 1992 GMT

AMSTERDAM, Netherlands (AP) _ The crash of a Boeing 747-200 cargo plane in Amsterdam this month was probably caused by a failure in the connection between the engine and the wing, according to the FAA. Passenger jets may also be at risk.

″The problem is not expected to be unique to freighter airplanes,″ the Federal Aviation Administration said in an Oct. 19 letter to crash investigators released Friday by the Dutch transport ministry.

The FAA said the Oct. 4 crash - in which an El Al cargo jet slammed into an apartment building, killing at least 43 people - and that of a 747-200 freighter in Taiwan last December were both caused by faulty pylon connections.

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″While neither accident investigation is complete, the probable cause of these two accidents appears to be related to a structural failure of the number 3 engine pylon-to-wing connection,″ Thomas E. McSweeny, deputy director of Aircraft Certification Service for the FAA, wrote in the letter.

The number 3 engine is the inboard engine on the right wing of the four- engine jet. The pylon assembly connects the engine to the wing.

McSweeny said it had not yet been determined which specific component had failed, and that the investigation would focus on all types of Boeing 747s.

″I want to assure you that the FAA ... will mandate any corrective action we find to be appropriate for the Boeing 747 fleet,″ McSweeny wrote.

On Oct. 9, the FAA ordered U.S. operators of most Boeing 747s to inspect engine pylon fuse pins and assemblies for corrosion and cracking. The pins, four to each pylon, are designed to snap should an engine seize up in flight. This allows the engine to fall away without damaging the wing and lets the plane continue flying on its remaining engines.

The FAA directive, which also was adopted by most foreign carriers, applied to all but about 160 Boeing 747s of the more than 900 passenger and cargo planes flying worldwide, Boeing spokesman Chris Villiers said in Seattle. The other planes, all with General Electric engines, use a different type of fuse pin.

McSweeny’s letter, sent to Henk Wolleswinkel of the Dutch Aviation Inspectorate, was the first time the FAA referred to a probable cause of the accidents in the Netherlands or in Taiwan, FAA spokesman Dave Duff said in Seattle, headquarters of the Boeing Co.

In Amsterdam accident, the El Al cargo plane slammed into a low-income housing complex in Amsterdam’s Bijlmermeer section after losing its two starboard engines. The plane had just taken off from Schiphol airport.

Dutch investigators believe engine supports gave way, possibly because of metal fatigue or corrosion in the four fuse pin assemblies which hold a plane’s engine to its wings.

In the Taiwan accident, a China Airlines 747 crashed shortly after losing both right engines. Five crew were killed.

Crash investigators reported no sign of serious damage in either of the El Al jet’s right-wing engines. They warned the FAA the airworthiness of 747 freighters powered by Pratt & Whitney engines could not be guaranteed beyond 6,000 flights.

McSweeny said that because no failed parts have been found in either crash, ″the FAA has looked at all reasonably probable events that could have caused these accidents. To date ... the only probable cause we have identified is cracking and eventual failure of the midspar fuse pins.″

McSweeny said initial checks by airlines on 26 Boeing 747s found corrosion on 74 fuse pins and four other pins that appeared to be cracked.

Boeing announced this week it was asking airlines to test 747s to assess the strains borne by engine supports.

Both Duff and Villiers said Boeing service bulletins and FAA orders had not singled out the freighters.