Grumman TS-2A and Grumman TS-2A mid-air collision near Hopland, California, August 28, 2001
On August 28, 2001 at about 1:40 am local time, 2 aircraft, Grumman TS-2A (N442DF) and Grumman TS-2A (N450DF), were involved in a mid-air collision near Hopland, California. 2 people were killed. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
the failure of both pilots to maintain an adequate visual lookout. The failure of the pilot in Tanker 87 to comply with suggested procedures regarding positive radio contact and orbit entry was a factor.
the failure of both pilots to maintain an adequate visual lookout. The failure of the pilot in Tanker 87 to comply with suggested procedures regarding positive radio contact and orbit entry was a factor.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 28, 2001 · about 1:40 am local time
- Place
- Hopland, California · map
- Type
- Accident · mid-air collision
- Injuries
- 2 people were killed.
- Weather
- visual conditions (good weather)
- Aircraft 1
- Grumman TS-2A
- Registration
- N442DF · registry record · serial 255
- Damage
- Destroyed
- Flight
- Public-use flight · public-use (government) rules
- Aircraft 2
- Grumman TS-2A
- Registration
- N450DF · registry record · serial 421
- Damage
- Destroyed
- Flight
- Public-use flight · general aviation rules (Part 91)
The NTSB's narrative for the Grumman TS-2A final · quoted from the NTSB record
During an aerial fire suppression mission for the California Department of Forestry (CDF), two Grumman TS-2A airplanes, operating as Tanker 92 (N442DF) and Tanker 87 (N450DF), collided in flight while in a holding pattern awaiting a retardant drop assignment on the fire. All of the airplanes fighting the fire were TS-2A's, painted in identical paint schemes. The Air Tactical Group Supervisor (AirTac) was orbiting clockwise 1,000 feet above the tankers, who were in a counterclockwise orbit at 3,000 feet mean sea level (msl). The pilots of both aircraft involved in the collision had previously made several drops on the fire. Records from the Air Tac show that Tankers 86, 91, and 92 were in orbit, and investigation found that Tanker 87 was inbound to enter the orbit after reloading at a nearby airport base. AirTac would write down the tanker numbers as they made their 3-minutes-out call, and usually ordered their drops in the same order as their check-in. The AirTac's log recorded the sequence 86, 91, 21, and 92. The log did not contain an entry for Tanker 87. Other pilots on frequency did not recall hearing Tanker 87 check in. Based on clock codes with 12-o'clock being north, the tankers were in the following approximate positions of the orbit when the collision occurred. 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. The 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. Post accident examination determined that Tanker 92's flaps were down, indicating that the pilot had configured the airplane for a drop. Tanker 92 swung out of the orbit wide (in an area where ground witnesses had not seen tankers all day) to move behind Tanker 86, and the pilot would likely have been focusing on Tanker 86 out of his left side window. Tanker 87 was on line direct to the center of the fire on a path that witnesses had not observed tankers use that day. Reconstruction of the positions of the airplanes disclosed that Tankers 86 and 91 would have been directly in front of Tanker 87, and Tanker 92 would have been wide to his left. Ground witnesses said that Tanker 87 had cleared a ridgeline just prior to the collision, and this ridgeline could have masked both collision aircraft from the visual perspective of the respective pilots. The right propeller, engine, and cockpit of Tanker 92 contacted and separated the empennage of Tanker 87. The propeller chop was about 47 degrees counterclockwise to the longitudinal axis of Tanker 87 as viewed from the top. The collision appeared to have occurred about 2,500 feet, which was below orbit altitude. CDF had no standard operating manual, no established reporting or entry point for the holding orbits, and a tanker could enter any point of the orbit from any direction. While no standardized procedures were encoded in an operating manual, a CDF training syllabus noted that a tanker was not to enter an orbit until establishing positive radio contact with the AirTac. The entering tanker would approach 1,000 feet below AirTac's altitude and stay in a left orbit that was similar to a salad bowl, high and wide enough to see and clear all other tankers until locating the tanker that it was to follow, then adjust speed and altitude to fall in behind the preceding airplane.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The NTSB's narrative for the Grumman TS-2A final · quoted from the NTSB record
During an aerial fire suppression mission for the California Department of Forestry (CDF), two Grumman TS-2A airplanes, operating as Tanker 92 (N442DF) and Tanker 87 (N450DF), collided in flight while in a holding pattern awaiting a retardant drop assignment on the fire. All of the airplanes fighting the fire were TS-2A's, painted in identical paint schemes. The Air Tactical Group Supervisor (AirTac) was orbiting clockwise 1,000 feet above the tankers, who were in a counterclockwise orbit at 3,000 feet mean sea level (msl). The pilots of both aircraft involved in the collision had previously made several drops on the fire. Records from the Air Tac show that Tankers 86, 91, and 92 were in orbit, and investigation found that Tanker 87 was inbound to enter the orbit after reloading at a nearby airport base. AirTac would write down the tanker numbers as they made their 3-minutes-out call, and usually ordered their drops in the same order as their check-in. The AirTac's log recorded the sequence 86, 91, 21, and 92. The log did not contain an entry for Tanker 87. Other pilots on frequency did not recall hearing Tanker 87 check in. Based on clock codes with 12-o'clock being north, the tankers were in the following approximate positions of the orbit when the collision occurred. 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. The 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. Post accident examination determined that Tanker 92's flaps were down, indicating that the pilot had configured the airplane for a drop. Tanker 92 swung out of the orbit wide (in an area where ground witnesses had not seen tankers all day) to move behind Tanker 86, and the pilot would likely have been focusing on Tanker 86 out of his left side window. Tanker 87 was on line direct to the center of the fire on a path that witnesses had not observed tankers use that day. Reconstruction of the positions of the airplanes disclosed that Tankers 86 and 91 would have been directly in front of Tanker 87, and Tanker 92 would have been wide to his left. Ground witnesses said that Tanker 87 had cleared a ridgeline just prior to the collision, and this ridgeline could have masked both collision aircraft from the visual perspective of the respective pilots. The right propeller, engine, and cockpit of Tanker 92 contacted and separated the empennage of Tanker 87. The propeller chop was about 47 degrees counterclockwise to the longitudinal axis of Tanker 87 as viewed from the top. The collision appeared to have occurred about 2,500 feet, which was below orbit altitude. CDF had no standard operating manual, no established reporting or entry point for the holding orbits, and a tanker could enter any point of the orbit from any direction. While no standardized procedures were encoded in an operating manual, a CDF training syllabus noted that a tanker was not to enter an orbit until establishing positive radio contact with the AirTac. The entering tanker would approach 1,000 feet below AirTac's altitude and stay in a left orbit that was similar to a salad bowl, high and wide enough to see and clear all other tankers until locating the tanker that it was to follow, then adjust speed and altitude to fall in behind the preceding airplane.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record for the Grumman TS-2A from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 12,725 hours in all; 340 in this make and model
- Last flight review: May 1, 2001
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: left
- Injury: fatal
The aircraft
- Airframe total time: 9,868 hours
- Last inspection: continuous airworthiness programme, August 23, 2001; 8 hours since
- Maximum gross weight: 27,000 lb
- Seats: 2
- Landing gear: retractable
- Engine 1: Curtis Wright R1820-82B (piston); 0 hours total
- Engine 2: Curtis-Wright R1820-82B (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: UKI Ukiah CA at 1:30 am
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 340° at 9 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 86°F (30°C), dew point 43°F (6°C)
- Altimeter: 29.87 inHg
- Observation at 1:56 am from UKI
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
The factual record for the Grumman TS-2A from the NTSB's investigation tables, in plain English
Pilot
- Certificate: airline transport pilot, commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 4,639 hours in all; 1,294 in this make and model
- Last flight review: May 1, 2000
- Medical certificate: Class 1 (valid medical--w/ waivers/lim.)
- Seat: left
- Injury: fatal
The aircraft
- Airframe total time: 10,354 hours
- Last inspection: continuous airworthiness programme, August 21, 2001; 8 hours since
- Maximum gross weight: 27,000 lb
- Seats: 2
- Landing gear: retractable
- Engine: Curtis Wright R1820-82B (piston); 0 hours total
- Fire on the ground
The flight
- Departed from: UKI Ukiah CA at 1:34 am
- Flight plan: none
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.