AUBEERY, CA, USA
N2742G
DOUGLAS C-54G
The tanker pilot was approaching the drop area when the copilot saw some static lines in front of the windscreen and alerted the pilot flying the aircraft. The pilot then dove below the lines before collided with them, severing the top 1/3 of the vertical stabilizer. Visibility was reported by those in the operation as good with some smoke from the fire which they considered not a factor. All pilots were advised of wires in the area and some had the lower set of lines in view. None of the pilots involved in the operation were aware of the higher set of lines 150 feet above the lower set, which were 140 feet above the ground. The other pilots following the accident aircraft, now aware of the higher lines, flew below these wires. This was the accident pilot's third pass over the fire area and the pilot was aware of the general terrain from previous operations. These unmarked transmission lines are depicted on the terrain map. However, the height of these lines was not passed on to the pilots, nor did the lead pilot see the higher lines along the tanker's route of flight when he made a clearing pass over the area just before the collision.
On August 23, 1995, at 1500 hours Pacific daylight time, a Douglas C-54G, N2742G, collided with some unmarked static lines during an aerial application of fire retardant on a fire near Auberry, California. Visual meteorological conditions existed at the time. The aircraft was substantially damaged and returned to Fresno, California. The two crewmembers were not injured. The aircraft is owned by Aero Union in Chico, California, and operated as a public-use aircraft by the California Department of Forestry (CDF). The aircraft had departed from Fresno at 1448. According to the CDF, the aircraft (Tanker 15) had made multiple runs on the local fire and was proceeding through a canyon area when the aircraft passed through two unmarked static lines that stretched across the canyon. The lines damaged the three propeller blades to the number 4 engine and severed the top 1/3 of the vertical stabilizer. The crew maintained control of the aircraft and made an uneventful landing at Fresno. At the direction of the NTSB Investigator-In-Charge, several interviews were conducted by CDF investigators with personnel involved in the accident. Their in-depth interviews are attached to this report. The following is a summary of those interviews. According to the Air Attack Officer-in-Charge of the fire fighting operation, a non-pilot, he indicated that he was aware of the power lines in the area. He advised the lead pilot of the wires and that he should not make the drop if he felt the conditions were unsafe. He had previously seen the lines that Tanker 15 eventually collided with, but was not aware of their height above the ground or the vertical distance between the two static lines and the sagging power lines below them. He was flying at 4,000 feet mean sea level (msl). He did not witness the collision. The pilot in the lead aircraft, a light twin-engine aircraft, had made a clearing pass and informed the pilots in several other tanker aircraft of the power lines in the area. He did not mention the height of the lines. He was behind Tanker 15 when he heard of the collision and circled around and proceeded to join on the damaged aircraft to assess the damage. According to this pilot, there was smoke in the area, but the visibility was clear. He saw the lower power lines when he passed over the area, but did not see the higher static lines. The pilot in Tanker 15 stated that he was aware of the power lines, and after being cleared for his run, he proceeded to turn right and continue down the drop line. He noticed quite a drift and moved the aircraft off to the side to further avoid the wires for safety purposes. As they descended to the drop point, the copilot looked out of the cockpit, saw the static lines, and called for engine power and flaps. The pilot then saw the lines in front of the windshield and went under the lines instead of trying to go over them because they were at a low airspeed with flaps extended. He said the visibility was clear and wasn't aware of the higher static lines on three previous passes in the area. The pilot in Tanker 96, following 1/4- to 1/2-mile behind Tanker 15, heard the warning about wires in the area and was not aware of the higher static lines above the power lines. He did not see the static lines until Tanker 15 collided with them. At this time, he felt he had enough room between the two sets of wires and elected to go under the static lines. He made the drop and then joined on Tanker 15 to help assess the damage. Another pilot following Tanker 96 saw the power lines but not the static lines. After the collision was reported, he saw the static lines and dove under them at an altitude of 150 feet above the ground. He radioed a warning about the second set of wires to the tanker pilot following him. He indicated that the higher static wires were located where one would not normally expect to find them. He felt that the warning about wires in the area was only marginally helpful in dealing with the existing wire hazard. The CDF prepared a diagram with photographs of the existing ground profile depicting the elevation of the terrain, the location of the wires, the height above the ground, and the distance between the two sets of wires. At the point of impact, the power lines were about 140 feet above the ground. The static lines were 150 feet above the power lines and are oriented along a south-southwest to north-northeast direction. The flight of the tanker aircraft was depicted on the map as flying along a northerly course.
failure of the pilot to see and avoid known obstacles along his route of flight. Contributing was the insufficient information given by the pilot in the lead aircraft.
Source: NTSB Aviation Accident Database
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