LAX96FA076

While conducting external load operations, the aircraft was orbiting east of a logging pickup site when the sling load contacted trees and terrain near a ridge. Weather at the time was clear with light winds. The helicopter was seen shaking and oscillating followed by a flat spin with the sling line still visibly attached. A radio call asking what was wrong was made with no reply. The first persons to reach the accident site found the belly hook and line still engaged. Evidence of freshly broken tree limbs and branches was found back along the flight path. Deposits of woody debris were also noted on sections of the lines and load. No discrepancies were found with the belly hook.

History of flight

On December 20, 1995, at 0925 hours Pacific standard time, a Hughes 369D, N8395F, collided with trees and terrain while maneuvering near Feather Falls, California. The aircraft was destroyed and the pilot, the sole occupant, received fatal injuries. The aircraft was being operated for external loads by Air, Inc., under 14 CFR Part 133, and was maintained under 14 CFR Part 135 when the accident occurred. The flight originated near Feather Falls at 0900 on the day of the accident. Visual meteorological conditions prevailed at the time and no flight plan had been filed.

The helicopter was in the process of slinging a 700-pound load of choker cables from a log drop-off site back to a log pickup site. Ground witnesses at two log pickup sites had been in radio contact with the pilot minutes prior to the accident. The pilot asked them if they were ready for him to bring in another load of choker cables. They replied that they did not need any cables at that time. The pilot began to orbit to the right about 0.5 miles east of the log pickup sites and was downwind of a Sikorsky CH-54 helicopter which was hooking up to a load of logs at one of the sites. Witnesses on the ground described the weather at the accident site as clear with a 5- to 7-knot wind blowing down the canyon from the logging operation and in the direction of the orbiting aircraft.

Two of the witnesses on the ground reported seeing the accident helicopter shaking and oscillating left and right, followed by a flat spin to the right with both sling lines still visible before it descended from view. During that sequence one of the witnesses made a radio call asking, "Robbie, what's wrong?" The transmission was monitored by other ground members of the logging operation; however, no one reported hearing any response from the pilot.

Upon reaching the accident site, investigators found both lines, which were still connected to each other at the remote electrical hook, lying along the flight path (175-degree bearing) within about 100 feet of the main fuselage. The line was disengaged from the belly hook, but the line hook was still a few feet from the belly hook. The first witnesses to reach the accident site reported that when they arrived the belly hook and the line were still engaged. However, while rescue personnel were attempting to remove the pilot, one of the rescue personnel inadvertently bumped the mechanical release, opening the belly hook and releasing the line. The end of that line was found on the ground near the nose of the aircraft.

About 600 feet back along the flight path, investigators found the first evidence of contact between the external load and the trees on the hilly terrain below. An 80-foot-tall tree near the top of a ridge was observed to have a visible break at its top. The 10-foot broken section from the tree was located about 100 feet further along the flight path. The broken section of tree exhibited fresh chaffing and scarring on its trunk with numerous smaller broken tree limbs and branches also lying in the vicinity. There was evidence that an object had been drug along the ground in the direction of the aircraft wreckage. Deposits of woody debris were noted on sections of the lines and on the bundles of choker cables.

Personnel information

The operator reported that the pilot completed his initial/new hire training on May 18, 1995. After each phase of training he was evaluated by the operator's chief pilot. His external load training was completed on May 14, 1995, in a Bell 204B. An additional external load check ride was given on October 20, 1995, in a Hughes 500D. Specifically, his external load qualifications included long line remote hook operations and mountain flying. A review of his training records revealed that he had completed all phases of his training successfully. The pilot also held an airframe and powerplant certificate and reported 17 years of maintenance experience on helicopters.

Coworkers reported to the operator that the pilot generally displayed a friendly cooperative attitude. On the day of the accident he appeared to be in his usual friendly attitude without any discernible preoccupation or mood alteration.

Aircraft information

The aircraft experienced a tail rotor strike and subsequent salt water landing on June 10, 1992. It was repaired and put back into service by Chet Rasberry on April 5, 1994. It had been configured to conduct long line operations in support of an aerial logging operation. The last annual inspection was completed on July 1, 1995, using the McDonnell Douglas Helicopter Systems 100-hour inspection checklist. However, that same check list also directs the completion of all 300-hour inspections in order to satisfy the annual requirements.

A review of the aircraft logbooks did not disclose any recurring deficiency or deferred maintenance items. A review of applicable airworthiness directives (ADs) and service notices (SNs) revealed 10 which were applicable but were not entered in the aircraft logbook. Included among them were: a tail rotor swashplate lockwasher inspection (AD), a tail rotor abrasion strip bonding inspection (AD), and a tail rotor abrasion strip modification (SN).

The empty weight of the aircraft was last verified by the operator on October 12, 1995. The aircraft's gross weight at the time of the accident was within gross weight and center of gravity limitations.

Specifically, the aircraft's task was to return sets of choker cables to ground crews who then prepared logs to be slung from the cutting location to a staging location where the logs were then loaded for surface transportation. The helicopter was equipped with a 150-foot sling line which was attached to the aircraft's cargo hook. The sling line was then connected to a 50-foot cable by means of a remote electrical hook positioned at the end of the sling line. The pilot was seated in the left seat for the external load operation.

Wreckage and impact information

The aircraft was located at latitude 38.39 degrees north and longitude 121.08 degrees west. The aircraft's final position was on a magnetic bearing of 300 degrees resting on its nose in a near 90-degree nose down attitude.

There was crushing and buckling visible on the forward canopy and cabin overhead canopy. The left front door was separated, while the right door was still attached and closed. The "A" frame assembly and the keel beam were intact and generally undamaged. The left forward cabin, including the canopy and door frames, revealed crushing and buckling.

The static mast base plate was intact. The main transmission, static mast, rotor head, and main rotor drive shaft had all remained attached to the airframe. A crush line extended approximately from the lower left front door fuselage station (FS) 40 aft to FS 56, upward to FS 85 and then diagonally forward and laterally to the center of the canopy frame. The tail boom was separated at FS 255.

There were numerous scars and breaks occurring in numerous 2- to 10-inch diameter trees along the final flight path and in the immediate impact site.

The airframe itself showed numerous buckles along both sides and the belly. The left skid tube was separated in several places.

An examination of all main rotor blades revealed extensive leading edge damage, as well as flapping and torsional bending. Both tail rotor blades were located and both blade roots were still in the blade grips, although one blade had separated. The tail rotor gearbox was still attached to the tail boom. The tail rotor drive shaft displayed breaks with "cork screw" deformation at several points between the transmission and the tail rotor gearbox. All tail boom and tail rotor components were located in the immediate vicinity of the final impact.

The instrument panel and console were still attached to the airframe and did not exhib