Skwentna, AK, USA
N688JK
Robinson R44
The commercial certificated helicopter pilot was transporting an external sling load and a passenger from a remote off-airport site on a Title 14, CFR Part 135 on-demand air taxi flight. He stated that after lifting a relatively light load on a short sling line, he transitioned to cruise flight. Shortly after entering cruise flight, he said he inadvertently allowed the cargo and sling line to strike the tail rotor blades. The cargo/cable disabled the tail rotor, and the pilot was unable to maintain control of the helicopter. The helicopter subsequently collided with terrain during the ensuing forced landing. The pilot indicated that there were no preimpact mechanical problems with the helicopter.
On May 29, 2006, about 1920 Alaska daylight time, a skid-equipped Robinson R44 helicopter, N688JK, operated by Ace Flyers, dba JayHawk Air, Anchorage, Alaska, had a loss of tail rotor effectiveness during an emergency landing, and sustained substantial damage when it collided with terrain, about 17 miles north-northwest of Skwentna, Alaska. The commercial certificated pilot and the sole passenger reported no injuries. The local flight was operating in day visual meteorological conditions as an on-demand, Title 14, CFR Part 135 air taxi flight when the accident occurred. During a telephone conversation with the NTSB investigator-in-charge (IIC) on May 30, the pilot reported that he was repositioning the passenger and a wire mesh cage from a remote drilling site near Sable Creek to a site nearby on the Kahiltna River. The pilot related that the wire cage was slung underneath the helicopter on a line about 18 feet long. He stated that about a minute after liftoff from the 1,200 feet msl site, following the transition to cruise flight, he looked outside the helicopter to try and see how the load was positioned. He said he could not visually acquire the load, and he suddenly heard an unusual noise and felt a shudder/vibration. He immediately jettisoned the load, and sought an emergency landing site close by. The landing site was a clear area in alder brush, on about a 15 degree slope. The pilot reported that the helicopter continued to vibrate and make unusual sounds as he came to a 2 foot hover over the landing site. When he increased the main rotor pitch with the collective control, the pilot said he stepped on the tail rotor control pedals, but there was "no pedal" and no response from the tail rotor. The helicopter quickly started to rotate, and immediately rolled onto its side as it touched the ground. The pilot stated that it was likely that the load on the tether line somehow struck or interfered with the tail rotor, although he could not see any damage to the tail rotor after landing. In his written statement to the NTSB, the pilot wrote in the section titled: Recommendation (How Could This Accident Have Been Prevented), "Pilot Error--I allowed a light load to catch the tip of the tail rotors."
The pilot's improper rigging of the external sling load, which allowed the suspended load/cargo cable to entangle and disable the tail rotor control, resulting in a loss of control during cruise and an in-flight collision with terrain.
Source: NTSB Aviation Accident Database
Aviation Accidents App
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