The Natural Resources and Environment Ministry will buy new helicopters as only five of the current fleet of 14 are fit to fly.
After grounding all ministry helicopters and aircraft, Minister Suwit Khunkitti inspected the 14 and found that only five of them were operational.
The inspection follows the tragic crash of the Frenchmade AS350 1103 in Nan on Tuesday.
The oldest aircraft is 24 years old while the youngest is 18 years old. The five are now undergoing maintenance while the ones unfit for operations might be put on display on Children's Day, Suwit said.
In addition to lacking navigational radar, the AS350 that crashed also had no emergency locator transmitter (ELT) installed in it, making it difficult to locate the helicopter after it crashed.
Only three operational helicopters are installed with radar and ELT units out of a total of five. The units are installed in helicopters chosen for each mission on a flightbyflight basis, Suwit said.
The ministry's aviation division chief, Prakit Wonsrirattanakul, said the aircraft that were unfit to fly would be sold, as repair and maintenance costs for each of them were estimated at around Bt30 million.
The new aircraft being considered for purchase between 2011 and 2012 include four helicopters, possibly two helicopters with one engine and two others with two engines, he added.
The proposal will be discussed at the Cabinet's weekly meeting next Tuesday, Suwit said.