N622PBHughes Helicopters HUGHES 369D · 1978

On August 18, 2008, at 1630 Pacific daylight time, a Hughes 369D, N622PB, collided with terrain near Bonners Ferry, Idaho. The United States Forest Service (USFS) was operating the helicopter as a public use flight. The helicopter sustained substantial damage; the commercial pilot and three passengers were not injured. Visual meteorological conditions prevailed and a visual flight rules (VFR) company flight plan and flight following were in effect. The pilot departed from Bonners Ferry Ranger Station about 1600.

According to a written statement submitted by the pilot, he departed from the Bonners Ferry Ranger Station to remove three firefighters and their gear from a mountain. He flew to the landing site and assessed the landing zone and winds, which were blowing out of the south from 5 to 7 knots. He landed the helicopter into the wind. The passengers and equipment were loaded and the pilot stabilized the helicopter at a 3 to 4-foot hover to check the power. The pilot departed into the wind and began a slow steady climb to clear trees that were 100 feet away, and about 10 to 15 feet higher than the takeoff point due to the down sloping terrain. At 30 feet above ground level and 40 feet from takeoff point, the helicopter started to descend toward the trees. The pilot applied additional power, but could not stop the descent. The pilot stopped forward movement in order to prevent impacting trees, applied right pedal, and rotated the helicopter about 270 degrees to land on the sloping terrain. The helicopter landed on downed trees and stumps. The pilot reduced the collective on landing and rolled the throttle off. The helicopter then slipped off of a log and nosed up 20 to 30 degrees, and the tail rotor impacted a log. After exiting the helicopter, the pilot noted that the winds were now blowing from the north. The passengers indicated that the winds had been shifting but they did not advise the pilot of this condition. The pilot did not report any mechanical malfunctions with the helicopter. A later interview with the pilot indicated that he had planned for hover in ground effect performance.

Post accident examination revealed that the tail rotor drive shaft was sheared.

Under the USFS contract, the pilots are required to have 2 full days off every 14 days. If travel during the off time is work related and exceeds 30 minutes, it is considered duty time. From August 1 until the time of the accident, the pilot worked 17 days and 182 hours.

Review of the load calculation showed that on the form, figures for a helicopter equipped with a Rolls Royce 250C20R were noted, rather than figures for the accident helicopter’s engine which was a Rolls Royce 250C20B. Actual payload for the previous day’s flight was recorded as 745 pounds. Review of the load calculation for the accident flight showed a gross weight at 2,940 pounds for the hover in ground effect, and a payload of 739 pounds. The hover out of ground effect was 2,840 pounds, with a payload of 639 pounds. Following the accident, the United States Forest Service investigator calculated the hover in ground effect weight at 2,820 pounds, and a payload of 619, and the hover out of ground effect as 2,660 pounds with a payload of 459 pounds. Using the actual weather conditions reported from the site, the hover in ground effect weight was 2,920 pounds with a payload of 719 pounds, and the hover out of ground effect was 2,720 pounds with a payload of 519 pounds.

The accident flight was the pilot’s first time operating out of the Fisher Peak landing site, which was located on a slope with vegetation and rocks. The site was established in 1994, and used in 2000, 2003, and from 2005-2007. There were no wind indicators at the landing site, which was required by the USFS. In preparation for the flight, the passengers wore hard hats instead of flight helmets. According to the Interagency Helicopter Operations Guide (IHOG), firefighters may use a hardhat with a chinstrap only when being transported as a passenger during fire operations from an established, managed helispot/helibase to another established, managed helispot/helibase.