NTSB Identification: NYC07IA023
14 CFR Part 91: General Aviation
Incident occurred Tuesday, November 07, 2006 in Harrisburg, PA
Probable Cause Approval Date: 04/30/2008
Aircraft: Eurocopter Deutschland EC135T1, registration: N522ME
Injuries: 1 Uninjured.
NTSB investigators used data provided by various sources and may not have traveled in support of this investigation to prepare this aircraft incident report.
After flying a patient to a rooftop hospital helipad, the medical crew and pilot decided to "hot offload" the patient (engines running). After the medical personnel and patient were unloaded, the "thumbs up" was given to the pilot verifying the helicopter's doors were secure and all equipment had been secured. The pilot then completed the before takeoff checklist. The pilot "pulled" the collective pitch lever, the helicopter became airborne, and began to "back up." He then discovered that he had forgotten to disengage the cyclic control lock mechanism after items, which had been carried on the front left seat, had been removed during the "hot offload." Fearing that the rearward movement of the helicopter may have taken him over the edge of the helipad, the pilot "immediately" lowered collective pitch, resulting in a hard landing. Examination of the incident aircraft's cyclic stick locking mechanism revealed that the locking mechanism installed on the helicopter was non-contrasting, and dark gray in color. Only three different cyclic stick locking mechanism color schemes had been produced by the manufacturer (light gray, black, or light gray with a yellow tip) and prior to the accident, a service bulletin had been issued, recommending that a yellow area be painted on the end of the older locking mechanisms to provide contrast. All aircraft produced subsequent to the service bulletin came equipped with a light gray and yellow cyclic stick locking mechanism. The cyclic stick locking mechanism was secured by means of a locking pin mounted on the underside of the instrument panel. In the event of an emergency, due to it not having been unlocked by the pilot, the locking pin was designed to be "sheared through" by a "jerky movement" of the cyclic stick, which would then allow it to move freely. The manufacturer evaluated the breakout force to be approximately 26.98 pounds of force at the stick grip. During a post incident interview, the pilot advised that he was unable to disconnect the cyclic stick locking mechanism even though he attempted to "jerk the stick." During an examination of the incident helicopter, breakout force was measured at approximately 44 pounds during one test and 42 pounds during another. Review of the operator developed checklist for the helicopter revealed that there was no reference to use of the cyclic stick locking mechanism, or inclusion of requirement to verify that the flight controls were free and correct. Additionally, the company operations manual did not address use of the cyclic stick locking mechanism during hot loading or unloading of passengers.
The National Transportation Safety Board determines the probable cause(s) of this incident to be: The pilot's inadequate preflight preparation, which resulted in the cyclic stick lock not being disengaged prior to lift-off, and his subsequent inability to control the helicopter. Contributing to the accident was the operator's inadequate procedures, the unmarked cyclic lock, and the excessive breakout force required. Full narrative available
Index for Nov2006 | Index of months