Lawsuit claims faulty PMA part downed helicopter

Aviation International News » May 2006
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September 19, 2006, 7:28 AM

A lawyer who filed a lawsuit on behalf of family members killed in a June 15, 2003, helicopter crash began taking depositions from defendant Rolls-Royce in March. Attorney Richard Genter of Jenkintown, Pa., filed the lawsuit on May 12 last year in the U.S. District Court of Hawaii. Genter is representing the families of the three passengers killed during a sightseeing flight in an MD 500D over Volcanoes National Park near Hilo, Hawaii.

According to the NTSB’s preliminary report, the MD 500D crashed after its engine failed. According to Genter, the engine quit because its compressor splined adapter coupling, which connects the compressor to the turbine, broke. The coupling was a part made by Gilbert, Ariz.-based replacement parts manufacturer Extex under FAA PMA (parts manufacturer approval) regulations.

While the NTSB released a preliminary report on the accident, no other factual information had been released at press time and a final report has not yet been completed. According to Jeffrey Guzzetti, NTSB deputy director for regional ops, “The investigation is being conducted from our regional office in Gardena, Calif. Due to recent resource constraints and current priorities in that office, the completion
of the investigation has been delayed; however, I anticipate the final report will be completed by this summer.”

The adapter coupling in the Rolls-Royce (formerly Allison) 250 that powered the MD 500D that crashed has been the subject of many FAA actions since the accident. In addition to Rolls-Royce, three other companies–Extex, Alcor Engine and Superior Air Parts–manufactured couplings for the Model 250. A portion of Superior became Extex after a buyout of Superior’s turbine product line in 1996. Alcor Engine is now owned by bearing and parts manufacturer Timken, which last December signed an agreement to work closely with Rolls-Royce to develop engine parts and repairs.

The lawsuit filed by Genter includes Rolls-Royce and Extex, but not Alcor, as well as the helicopter tour-arrangement company, the operator, the maintenance provider and the helicopter manufacturer. The family members are seeking compensatory damages for wrongful death and survival “in an amount to be proven at trial,” plus prejudgment interest, attorneys’ fees and costs and general, special and punitive damages.

The complaint alleges that “the accident helicopter, the accident engine and/or their component parts were defective in design and/or manufacture, were defective for lack of warnings and instructions and were in an unreasonably dangerous and unsafe condition, which was a substantial factor in the happening of this accident.”

Safety Warnings Issued

Following the June 2003 Hawaiian accident, the FAA issued three non-mandatory Special Airworthiness Information Bulletins (SAIBs), all dated March 24, 2004, warning operators that there might be a problem with the Rolls-Royce 250 compressor splined adapter coupling. Each of the three SAIBs applied to each manufacturer of the couplings, Rolls-Royce, Alcor and Extex. Oddly, the FAA neglected to specify the number of coupling failures in the SAIBs for Alcor and Rolls-Royce.

In the Extex SAIB (NE-04-58), the FAA noted, “We have received reports of the failure of two Extex compressor splined adapter couplings. The most recent failure of the Extex coupling was due to fatigue originating from fretting on the outer diameter of the coupling where it mates with the compressor impeller. The compressor splined adapter coupling is part of the shafting system between the gas generator turbine and the compressor. Failure of this part results in immediate and total loss of power from the engine.”

In the Alcor SAIB (NE-04-57), the FAA wrote, “We have received reports of failure of Rolls-Royce and Extex compressor splined adapter couplings.”

The Rolls-Royce SAIB (NE-04-56) was equally vague: “The FAA has received reports of failures of Rolls-Royce compressor adapter couplings.”

The FAA then issued an Airworthiness Directive–AD2004-26-09–that calls for early removal of affected Rolls-Royce 250 adapter couplings. The AD became effective Feb. 8, 2005, one year and eight months after the accident. Per the AD, operators must remove from service Extex, Superior and Alcor couplings with part numbers that include “23039791” and that may include prefixes and dash number of -1, -2 and -3.

The Rolls-Royce/Allison 250 engines in which these adapters were installed power a variety of aircraft, including the Agusta A109, Bell 206 and 207, Enstrom TH-28 and 480, Eurocopter AS 355 and BO 105, MD Helicopters 369, Schweizer 269D and Britten-Norman BN-2T Islander.

Service Requirements

The affected couplings, with the exception of the Rolls-Royce coupling, must be removed generally at the 600-hour mark or within the next 50 to 150 hours. The AD specifies that Rolls-Royce couplings must be removed “the next time the compressor rotor is disassembled for any reason, but not later than March 1, 2012.”

The AD text gives no reason why the Rolls-Royce coupling can remain in Model 250 engines longer than the PMA couplings made by Extex, Superior and Alcor. However, the FAA did address a comment on that question: “One commenter requests an explanation of the year 2012 compliance time for the Rolls-Royce couplings. The commenter states there may be less attention given to this problem if there is a 7.5-year compliance period.

“We do not agree. As stated in the proposal, each manufacturer is responsible for its independent component design, design substantiation, component manufacture and development of a field-management plan for its fleet. An important element of the field-management plans is the risk assessment. The varying outcomes of those independent risk assessments lead to differing compliance intervals. The compliance time for Rolls-Royce couplings is not intended to convey the message that there is little risk. Operators are expected to use the compliance time to schedule the maintenance actions required by this AD.”

The PMA parts made by Extex, Alcor and Superior were certified using the “test and computation” method outlined in the PMA regulations (FAR Part 21.303). This means that each PMA manufacturer had to prove to the FAA that its couplings accurately replicated the Rolls-Royce coupling by testing and measuring the original and duplicating precisely its design and material makeup.

According to the AD, “This AD results from nine reports of engine shutdown caused by compressor adapter coupling failure.” The AD neglects to say which manufacturers’ couplings failed, although of three Rolls-Royce/Allison 250 engine-failure accidents involving failure of the coupling that AIN was able to find in NTSB records, two involved failed Rolls-Royce couplings and one–the Hawaii accident–involved a failed Extex coupling. Genter told AIN that he has in his possession a failed Alcor coupling.

Extex president Larry Shiembob told AIN that his company stopped manufacturing and marketing the adapter couplings about a year before the Hawaii accident. “I think we took the appropriate action by getting them out of service quickly,” he said, “which was proven by the fact that there have been no more failures.”

The FAA estimates that about 6,000 of the existing 9,000 Model 250-B and -C engines are affected by the AD. The cost of parts is estimated at $1,601 per engine plus the labor cost of three hours at $65 per hour, if done when the rotor is disassembled. To comply with the AD, some machining of the compressor impeller must be done, and a new Rolls-Royce 23076559-2 or -3 coupling must be installed, or a new -1 coupling with a new impeller.

The FAA did not say how many of the Extex, Alcor and Rolls-Royce couplings remain in engines in the field.

Asked if Rolls-Royce is planning to redesign the 250 shafting system, a company spokesman responded, “Due to the ongoing litigation, we are unable to respond to any media requests related to the incident at this time.”

The trial is scheduled to begin in January, according to Genter.

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Valdir Gonçalves
on April 3, 2013 - 9:03pm

I need buy the parts number 23076559-2
Coupling

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