BIG SKY, MT, USA
N5803J
Aerospatiale SA-315B
The helicopter was engaged in logging operations associated with the clearing of a recreational ski lodge construction site. This was the first time the operator had worked with this particular ground crew (chokers). The chokers were briefed by the pilot-in-command (PIC) and were supposed to hook up only two marked logs at a time (marked with orange fluorescent paint). However, they hooked up three logs together, one of which was still rooted. During the lifting operation, the PIC encountered resistance and attempted to electrically release the long line several times without success. The failure of the long line to release was due to jamming because of the use of an oversize clevis attaching the hook. When the long line finally released after the use of the manual system, the helicopter rotated along its longitudinal axis at such an angle that the tail rotor contacted trees and separated from the aircraft. It then descended out of control until impacting the ground. Winds at the site were strong and gusty.
On October 5, 1998, approximately 1430 mountain daylight time, an Aerospatiale SA-315B Lama, N5803J, registered to and being operated by Central Copters, Inc., and being flown by a commercial pilot, was destroyed during an in-flight collision with trees and terrain following a loss of control near Big Sky, Montana. The pilot sustained minor injuries. Visual meteorological conditions prevailed and no flight plan had been filed. The flight, which was engaged in logging operations associated with the clearing of a recreational ski lodge construction site, was to have been operated under 14CFR133, and originated from a location near the accident earlier in the afternoon. The pilot reported in his written statement (NTSB Form 6120.1/2 attached) that during logging activities the "hooker 'accidentally' attached chockers [sic] to log that was attached to ground by root system. Helicopter attempted to lift logs & was abruptly stopped by log. Helicopter was pitched back and weight of logs on long line aggrivated [sic] backward movement. Pilot, in the interest of safety, decided to release long line and load. When pilot activated the long line release the load beam dropped down but this particular lifting eye on the long line wedged in throat of hook. (This was the first time this lifting eye was ever used.) At this time the pilot reached the forward stop on the cyclic control, to try to move the helicopter forward back over the load. The helicopter continued to move backward. The weight of the logs & the long line attached to the cargo hook on the bottom of the helicopter prevented the helicopter from moving forward. The helicopter with line & load attached quickly backed up into trees. Line did come loose from hook at this point & helicopter did move backward before coming to a stop on the ground." An inspector from the Federal Aviation Administration (FAA) Flight Standards District Office (FSDO) at Helena, Montana, interviewed the pilot. The inspector reported that "This was the first time they (the operator) worked with this ground crew. The pilot stated he thoroughly briefed the ground crew but was not comfortable with them. The ground crew (chokers) were supposed to hook up only marked logs (orange fluorescent paint) and only 2 at a time [refer to photograph 1]. On the lift that started the accident sequence, the choker had hooked up 3 logs and one was not marked. The non-marked log was still rooted in the ground [refer to photograph 2] and the other end was not bucked (trimmed off). It finally released from the ground with the helicopter as a pendulum at the other end of the long line. The helicopter rotated along its longitudinal axis at such an angle that the tail rotor contacted trees [refer to photograph 3], and separated from the aircraft. The winds were reported as strong and gusty" (refer to ATTACHMENT FAA-I). The inspector continued reporting that the "pilot stated that he had attempted to release the load several times, but it did not release from the helicopter. He tried first to release via the electrical release on the cycle [sic] but with no release. The manual release is along side of the collective and a pilot has to release the collective to engage the manual release. The pilot eventually pulled the manual release and the load did release" and that "the pilot later called us and stated the electrical release was operational. He said the reason the load did not release initially was, that he was using an oversize clevis attached to the hook. He had been using this clevis on the K-MAX which has a larger hook. When he used it on the Lama with a smaller hook, it would not allow the hook to open until it got to a certain obtuse angle" (refer to ATTACHMENT FAA-I). The pilot reported the winds at the time of the accident were from 225 degrees at 10 knots with gusts to 20 knots. Winds at 1456 hours at Bozeman, Montana, 32 miles north of the accident site were reported as from 240 degrees (magnetic) at 15 knots with gusts to 18 knots.
The failure of the ground handlers (chokers) to follow procedures, and separation of the tail rotor system. Contributing factors were incorrect long line hook (size), jamming of the hook release, trees and gusty wind conditions.
Source: NTSB Aviation Accident Database
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