Washington, DC -- The National Transportation Safety Board today issued two urgent recommendations to the Federal Aviation Administration to address a safety issue concerning a failure that resulted in uncontrollable engine thrust in an Eclipse 500 airplane and the lack of emergency procedures developed for that failure.
The Safety Board recommended that the FAA should require immediate inspection of all Eclipse 500 airplane throttle quadrants to ensure that pushing the throttle levers against the maximum power stops will not result in an engine control failure, and that the FAA should further require that all units that fail inspection be replaced and replacement parts be similarly inspected.
The Board also recommended that the FAA require Eclipse to immediately develop for the Eclipse 500 airplane an emergency procedure for a dual engine control failure and incorporate the procedure into the airplane flight manual and quick reference handbook via an airworthiness directive.
On June 5, 2008, an Eclipse 500 airplane, N612KB, on approach to Chicago Midway Airport, experienced a failure that resulted in uncontrollable maximum power thrust from two Pratt & Whitney Canada PW610F turbofan engines. After referencing the emergency procedures of the airplane’s quick reference handbook, the pilots shut down one of the engines.
However, following the shutdown of the engine, the other engine rolled back to idle power and continued to be unresponsive to the throttle. The pilots declared an emergency, were cleared to land on any runway and were able to land the plane without injury to the two pilots or two passengers.
“The Eclipse 500 is still a new aircraft model, with some 200 hundred having been delivered,” NTSB Chairman Mark V. Rosenker said. “This incident demonstrated a technical safety-of-flight issue that we believe needs immediate attention.”
The Safety Board noted that the dual-channel failure of both throttle levers occurred after the airplane had accumulated only 238 hours and 192 cycles since new. As a result, the Board is concerned about the reliability of an assembly that fails in such a short time.
Furthermore, when the failed throttle quadrant assembly was replaced on the accident airplane, pushing the throttle levers on the replacement unit against maximum power stops caused an R ENG CONTROL FAIL message to appear on the crew alerting system display.
The Board further noted that the Eclipse 500’s flight manual and quick reference handbook provide an emergency procedure for a single engine control failure, but not for a dual engine control failure, such as occurred in the incident. The Safety Board is concerned that should there be another dual engine control failure aboard an Eclipse 500, pilots will be without guidance and may be unable to restore control.
On Tuesday, June 10, 2008, the Safety Board gave a preliminary briefing to the FAA on the status of its investigation into this incident and informed the agency of the Board’s intention to issue urgent recommendations.
The Safety Board is continuing its investigation.
A copy of the Board’s safety recommendation letter may be accessed on the NTSB’s website at the following link: www.ntsb.gov/Recs/letters/2008/A08_46_47.pdf.
