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On March 3, 1996, at 1558 central standard time (cst), a Hughes 369E, N7065C, registered to Haverfield Corporation, of Miami, Florida, and piloted by a commercial helicopter pilot, sustained substantial damage after losing total power while engaged in construction work on a utility powerline pole. The pilot reported no injuries. The crew member sustained serious injuries. The 14 CFR Part 133 operation was operating in visual meteorological conditions. No flight plan was on file. The local flight had departed on this mission at 1435 cst.
The pilot completed two earlier flights that day with a third flight scheduled. The normal sequence flown was to complete six utility powerline poles with approximately 300 pounds of fuel due to the payload requirements. The company was running behind on their powerline installation contract due to unforeseen delays.
The pilot started the helicopter at 1423 cst to begin the third flight for the day. The pilot said that he had taken on just under 350 pounds of fuel on a slight incline at the remote landing zone. The pilot lifted off at 1435 cst to start the first of six structures located one minute away from the landing zone. On the fifth structure the pilot noticed the fuel gauge at 150 pounds. Upon the sixth structure the pilot noticed the fuel gauge below 100 pounds. At 1558, with 1.6 hours total flight time, the pilot was heard saying "uh-ohhh" on the headset. This transmission was followed by a total power loss. The pilot maintained altitude by using collective to stay clear of the structure. Once clear, the pilot lowered collective to regain rotor RPM. The pilot used full collective just prior to impact. He then banked the helicopter to the right in an attempt to prevent injury to the crewmember on the end of the platform on the left side of the aircraft and to prevent the rotor blades from flexing on the crewmember. The rotor blades impacted the terrain to the right, bending them upward (gull wing coning). The rotor blades had full collective pitch with corresponding high blade angle noted.
The pilot held a commercial certificate for helicopters. He was born November 1, 1954. He had a total pilot time of 6,533 hours in all types of aircraft, with 3,597 hours in the make and model of the accident helicopter at the time of the accident. He was the holder of a second class medical certificate issued on November 1, 1994, with an eyeglass limitation for distance. His most recent biennial flight review was conducted in this make and model of helicopter 3 months prior to the accident. His second class medical certificate had expired into a third class medical on November 30, 1995.
The helicopter was a Hughes 369E, N7065C, serial number 0303E. The helicopter had accumulated 4,698.3 hours time in service at the time of the accident. A Federal Aviation Administration (FAA) approved progressive maintenance inspection "C" was conducted on February 13, 1996, and the helicopter had accumulated 75.4 hours time in service since the inspection. The total time on the engine was 6,806.5 hours. The helicopter was equipped with an external cargo rack and work platform located between the skid gears in accordance with the Federal Aviation Administration Supplemental Type Certificate number SH1861SO.
WRECKAGE AND IMPACT INFORMATION
Marks corresponding with the size of the right landing skid were found due west of the powerlines on an entry driveway to the Farms and Bureau Building. This was the initial touchdown point on a heading of 180 degrees. The ground scars ended within 5 feet to the west. The helicopter came to rest in a right 40 degree bank, on a heading of 180 degrees.
A continuity check of the flight control system (collective, cyclic, and directional) was completed with no pre-impact discrepancies noted. An inspection of the collective/throttle control linkage to the governor/fuel control system showed evidence of damage from impact to the right side of the helicopter. The tailboom control rod remained attached to the tail rotor gearbox bellcrank and when moved, showed no damage or malfunction of the tail rotor pitch control system.
The main rotor system (hub assembly) showed minor damage with lead/lag excursions and excessive blade flapping (chord-wise). The hub assembly had impact marks consistent with main rotor blade strikes. All main rotor blades remain attached to the rotor head and exhibited gull wing bending.
The drive system was examined. The over-running clutch functioned when inspected. From the engine to the transmission driveshaft there was no evidence of damage. The main rotor system and tail rotor driveshaft rotated when the driveshaft was turned by hand. The tail rotor gearbox rotated in both directions and showed no evidence of lockup or ratcheting. The tailboom had a torsional twist at fuselage station 243. The engine showed no evidence of displacement or damage. All engine fuel and air lines were inspected and no evidence of damage or looseness was observed.
All five main rotor blades remained attached to the main rotor hub assembly. They all exhibited spanwise and chordwise bending. The yellow main rotor blade elastometeric vibration absorber was torn out of its housing and remained attached to the blade. The blue main rotor blade elastometeric vibration absorber was partially separated from its housing and the bolt was sheared at the attachment point to the blade. The green, white, and red main rotor blade elastometeric vibration absorbers remained intact.
Inspection of the fuel system revealed that the helicopter was equipped with an auxiliary fuel tank which remained intact and showed no evidence of leakage. The auxiliary fuel tank showed no fuel present. A member of the ground crew stated they did not use the auxiliary tank due to the payload. The main fuel tank showed no evidence of damage, or leakage and contained only 20 ounces of fuel after being drained. The unusable fuel for the main fuel tank is two and one half gallons. Two teaspoons of fuel were found in the fuel control line to the spray nozzle. The fuel vent system was inspected to verify that the vent was open. No restriction was noted.
TEST AND RESEARCH
On March 4, 1996, a test of the fuel system was conducted. The main fuel tank sending unit was removed. With battery power switched to on, the fuel tank sender unit was moved from full position to empty position. At about 50 pounds, the low fuel warning light illuminated on the enunciator panel. The system worked with no abnormalities found.
Parties to the investigation were the Federal Aviation Administration, Flight Standards District Office, Wichita, Kansas; Allison Engine Company, Indianapolis, Indiana; Haverfield Corporation, Miami, Florida.
The aircraft wreckage was released to Haverfield Corporation on March 6, 1996.