There are 14 OV-10 aircraft used throughout the state. The fleet has an outstanding safety record, CDF Battalion Chief Rick Moore said.
In his 32 years in CDF, he said he can't recall a plane crash involving a spotter plane.
"They have been a very reliable instrument for the department," Moore said. "I feel very comfortable flying them, and I think others will say the same about them."
CDF has owned the Vietnam-era, twin-engine "Bronco" fleet for more than 25 years, Moore said.
The "air tactical group supervisor," the formal name for a "spotter" plane, coordinates area rescue efforts and air traffic control on a CDF incident, Moore said.
The plane that crashed Wednesday handled air reconnaissance for the entire county.
It was likely in the air every day this week, Moore said, as the agency has dealt with a number of fires during the Labor Day weekend.
Because of the nature of the usage, maintenance on the planes is constantly ongoing, Moore said.
"I know for a fact that when you land, a mechanic is sitting there, asking you how the flight was, if you had any problems," Moore said. "Maintenance is happening constantly, every hour the mechanics are looking at something."
The fleet's pilots - contracted from Texas-based DynCorp International -- are also well-trained, logging hundreds of individual flight hours, Moore said.
"Most of the pilots are ex-military, so they get a lot of training before coming to us," Moore said. "I can't say for sure how many hours this pilot had, but it's probably a bunch."
Planes from neighboring CDF air-attack bases will cover Tulare County incidents for the time being, Moore said.
"It's the same thing when we swap out fire crews, we will use ones from neighboring counties," Moore said. "They've already used planes from nearby counties today."
About the men
Stone, 36, was a Visalia resident and an 18-year CDF employee.
Redwine said the battalion chief was popular among his colleagues.
"Robert was well-liked and had a lot of friends, we all knew him," Redwine said. "He's got little kids."
Stone is survived by his wife, Mary Marinda "Rindi" Stone, and his two children; Wil, 8, and Libbie, 4.
Willett, 52, a Hanford resident, was a DynCorp pilot for four years.
He is survived by his wife, Judy, of Hanford.
"I don't know the pilot as well, but he was with the department, he's family," Redwine said.
The department, Moore said, will lose two dedicated workers.