N442DF

1.1 HISTORY OF FLIGHT

On August 27, 2001, about 1840 Pacific daylight time, Tanker 87, a Grumman TS-2A, N450DF, collided with Tanker 92, a Grumman TS-2A, N442DF, near Hopland, California. The California Department of Forestry (CDF) was operating the airplanes as public-use fire suppression flights under the provisions of 14 CFR Part 91. Tanker 87's pilot held an airline transport pilot certificate; Tanker 92's pilot held an airline transport pilot certificate. The collision sequence and post crash fires destroyed both airplanes. Tanker 92 departed Ukiah, California, at 1830, and Tanker 87 departed Ukiah at 1834. Visual meteorological conditions prevailed, and no flight plans had been filed. The primary wreckage for Tanker 87 was at 39 degrees 00.878 minutes north latitude and 123 degrees 11.603 minutes west longitude, at an estimated elevation of 1,955 feet. The primary wreckage for Tanker 92 was at 39 degrees 01.089 minutes north latitudeand 123 degrees 11.65 minutes west longitude, at an estimated elevation of 2,150 feet.

WITNESSES

1.1.1 AirTac

An airborne observer who was not a pilot served as the Air Tactical Group Supervisor (AirTac). AirTac orbited the fire in a clockwise pattern about 2,000 feet above ground level (agl). The tankers orbited in a counterclockwise pattern about 1,000 agl. AirTac remained in contact with the incident commander on the ground, and directed the tanker drops on the fire. AirTac directed the tankers on their drop order, and described the desired target point for the drop.

The first tankers arrived on scene prior to AirTac, and established a tanker pattern altitude of 3,000 feet mean sea level (msl). AirTac arrived and began an orbit at 3,500 feet. He moved up to 4,000 feet msl by the end of the day. As tankers approached the scene, they made a 3-minutes-out call; if the frequency was congested, they made a 2-minute or 1-minute call. Most tanker pilots reported that they made a direct path from Ukiah to the fire, and entered the orbit about 150 knots. Several pilots noted that the air-to-air frequency was heavily congested.

AirTac said that three helicopters and eight tankers were working the fire. Not all aircraft were on scene at the same time. Tanker 92 had already made five drops, and Tanker 87 had already made six drops. Tankers 92, 86, and 91 were in orbit.

Based on clock codes with 12-o'clock being north, the tankers were in the following approximate positions of the orbit when AirTac called Tanker 86 in to drop. Tanker 92 was at the 2-o'clock position; Tanker 86 was turning in at the 5-o'clock position; and Tanker 91 was in the 7-o'clock position. AirTac's log indicated that Tanker 92 was going to move up in sequence and follow Tanker 86 in order to drop immediately after him in what the tanker crews call a daisy chain. The AirTac was heading westbound in the 6- to 7-o'clock position.

1.1.2 Tanker 86

As Tanker 86 set up to enter the drop pattern, he heard Tanker 92's pilot say that he had him in sight and was going to swing wide. He assumed that Tanker 92's reference was to himself. At this point, Tanker 86 was south of Bus McGall Peak and turning to the west about 2,500 feet msl. During the left turn, the pilot of Tanker 86 reached up to prepare his airplane for the drop. As he looked to his front right position, he observed the two airplanes collide.

1.1.3 Tanker 91

Tanker 91 departed runway 33 at Ukiah. The pilot stated that he had just entered the orbit, and had not made a complete pattern. Tanker 92 was physically ahead of Tanker 86 in the orbit. He heard Tanker 92's pilot say: "I've got you in sight. I'll go wide." He initially thought that 92 was referring to Tanker 86, and swinging wide of the dropping tanker would be the proper thing to do. However, he became unsure of whom 92's pilot was referencing since he now saw another tanker in Tanker 92's proximity. Although Tanker 92 said that he was going wide, the airplane never went right. It continued in a continuous left turn, like tankers always are. Tanker 91 only saw the approaching tanker for about 5 to 6 seconds. He did not see any evasive action. The approaching tanker was either in a climb or pulled up a split second prior to the collision.

1.1.4 Tanker 21

The aircrew in Tanker 21 reported that they were coming from Medford, Oregon, and checked in over Lake Mendocino. They fell about 2 miles in trail of Tanker 87 as it left Ukiah on a right downwind departure. They followed it in a southerly direction along the hills east of the Ukiah valley, and as it turned to a southwesterly heading toward the fire. As they headed toward the fire, the copilot said that AirTac was talking to Tanker 92 and explaining the drop. To the copilot, this meant that Tanker 92 was preparing to drop.

Tanker 21's altitude was about 3,500 feet, and they estimated that Tanker 87 was at 3,000 feet or below. Tanker 87 was entering the orbit directly toward the center of the fire rather than making a wide orbit. They observed a second tanker approach from southeast to west. The pilot estimated that the two airplanes were converging at a 60-degree angle. The copilot said that Tanker 87 cleared a ridgeline, and pulled up just prior to impact. He did not observe any avoidance maneuver by the westbound tanker, whose right wing was up. They observed Tanker 87 continue in a southerly direction, and it rolled left. The other tanker rolled 90 degrees wing low and nosed down about 60 degrees as it continued toward the west.

1.1.5 Ground Witness 1

A ground witness was on a promontory point observing the horizon to the west for signs of the fire. This observation point was about 1,900 feet elevation and 1 mile east of the accident site. This witness observed a tanker northwest of her position that was proceeding southbound on a track that she had observed other tankers use during the day. As she looked back to the west, she observed another tanker south of her position that was proceeding in a westerly direction. She had not seen a tanker in this area during the day. She observed the tankers as they converged and collided. The westbound tanker went under the southbound tanker. She could see the top of Goat Rock (about 2,400 feet elevation) above the two airplanes.

1.1.6 Ground Witnesses 2, 3, and 4

Several ground witnesses (including the incident commander) were together at the edge of a meadow in a saddle (about 2,000 feet elevation) between Goat Rock and Bus McGall Peak (about 2,200 feet elevation and 1/2 mile southeast of Goat Rock).

The incident commander was also a relief air attack pilot. He was facing east with maps on the hood of a car as he was briefing other ground commanders. He looked east, and saw two tankers in the orbit; this was the orbit that he had been observing other airplanes use during the aerial firefight. He estimated that the tanker farthest away was on a 45-degree angle from the closest airplane. Based on his experience, he felt that the airplane on the inside was preparing to make a drop. He felt that the pilot of the far airplane was watching the closer airplane so that the far pilot would know where to drop. He thought that the far airplane was in a slight left turn. With his peripheral vision, he detected a third airplane. All three airplanes appeared to be about the same altitude. He estimated that the airplanes were only a few hundred feet away horizontally, and several hundred feet vertically from his location. He had not seen an airplane enter the pattern at the third airplane's location. Most pilots entered a wide pattern north of Goat Rock and gradually tightened their radius as they descended into the orbit. He expected the pilot of the third airplane to make a hard right to enter the left orbit; however, it did not.

All of the witnesses in the saddle observed the southbound tanker heading straight for them, and then observed the westbound tanker. The westbound tanker slid below the southbound tanker. A spherical cluster of debris emanated from the collision point, which was about 400 yards away on the opposite side of a meadow. The westbound tanker continued westbound and did not seem to have a tail. The southbound tanker continued straight toward them; it seemed to one witness that the nose pitched down, then slightly back up, and pitched down until the nose was vertical to the ground. They observed the tail of the southbound tanker twirl and separate. This airplane exploded on ground contact about 200 feet from their location. They observed smoke coming from the direction of the other tanker.

1.1.7 Ground Witness 5

Another ground witness observed the westbound tanker fly over him. He was getting water from a pond. When he first observed the tanker, it was just rolling out of a bank. It continued up the valley that he was in, and remained in a level attitude as it flew away from him. He observed the southbound tanker moving from his right to left. Just prior to impact, it appeared to him that the westbound tanker turned left, and the southbound tanker tried to climb.

1.5 PERSONNEL INFORMATION

1.5.1 Tanker 92 Pilot

A review of Federal Aviation Administration (FAA) airman records revealed that the pilot of Tanker 92 held an airline transport pilot certificate with an airplane multiengine land rating. He held a commercial pilot certificate with an airplane single engine land rating. He held type ratings in the CE-500 and G-S2. The pilot held a second-class medical certificate issued on May 11, 2001. It had the limitations that the pilot must wear corrective lenses for near and distant vision. The operator reported that he had 12,725 hours of total flight time with 340 in this make and model. He accumulated 2 hours in the previous 24 hours.

1.5.2 Tanker 87 Pilot

A review of FAA airman records revealed that the pilot of Tanker 87 held an airline transport pilot certificate with an airplane mult...