Swiss RJ100 in in-flight incident despite four-year-old FAA airworthiness directives

An uncontained Honeywell LF507 engine failure that disabled the engine next to it on a BAE Systems Avro RJ100 occurred despite a series of US Federal Aviation Administration airworthiness directives (AD) over four years aimed at reducing just such a risk. This is the first known occasion in the 146/RJ series in which a failure in one engine has caused another to be shut down.

The No 2 (left-hand inboard) LF507-1F on a Swiss International Air Lines RJ100 suffered an uncontained failure, and the No 1 engine also had to be shut down when it generated a fire warning after being hit by debris from the failed power unit, according to the German accident investigation unit BFU.

The incident occurred on 9 August over southern Germany en route from Amsterdam to Zurich, and the aircraft (HB-IXU) diverted to Frankfurt Main airport for an emergency landing using only its two right-hand engines. None of the five crew or 51 passengers was injured.

Honeywell declines to comment on the incident, other than confirming that it has "been invited" to participate in the inquiry. Swiss says only that it is pleased the crew handled the emergency so competently, and BAE has been unavailable for comment.

A US-registered RJ100 of Colombian airline SAM suffered a catastrophic LF507 turbine failure on 18 September 1999, says a US National Transportation Safety Board report, causing damage to the flaps, wing and engine mounting, but the aircraft landed safely. Since then the engine has suffered failures of the oil system and bearings.

The engine manufacturer supports 818 LF507s that have amassed about 11 million hours in service. But the LF507, along with its ALF502 stablemate, has been the subject of several FAA ADs over the past four years - at least three of them designed to counter the risk of an uncontained failure.

The latest AD aimed at reducing containment failure risk was issued in July 2002. The FAA ordered the removal of first-stage turbine rotor sealing plates and rotor discs as well as spacers on about 300 of the 1,600 ALF502/LF507 engines in service.

In April 2000 an AD required rework or replacement of the No 4 and 5 bearing oil system to protect the reduction gear and overspeed protection systems, and reduce the risk of a fourth-stage low-pressure (LP) turbine rotor failure.

Three months later, another AD ordered enhanced inspections of several life-limited parts, including the fan, first-, second- and fourth-stage LP turbine discs, the impeller, LP turbine shaft and third-stage turbine.



Source: Flight International