TOKYO, May 16 (Xinhua) -- Japan's defense ministry said Tuesday that Self-Defense Force (SDF) personnel have found all four male crew members of a Japanese Ground Self-Defense Force (GSDF) aircraft that crashed in a mountainous region of Hokkaido in northern Japan on Monday.
The ministry said the four crew members have been transferred by helicopter to an SDF base in Hakodate and are feared dead.
But official announcement on their conditions are yet to be made.
Wreckage of the plane was first discovered earlier in the day by search and rescue officials and debris from the plane was scattered over a wide area of land about 3 km from the peak of Mt. Hakamagoshi in the city of Hokuto in Hokkaido, the defense ministry said.
The crash site was located about 14 km from downtown Hokuto and due to the thickness of forestation covering the mountain and poor visibility due to heavy cloud coverage, search and rescue efforts were impeded.
The wreckage of the plane had been shattered into small pieces, according to local accounts, making it difficult to identify specific parts of the plane, including the overall air frame.
Pieces of wreckage believed to be from the fuselage of the plane that went missing a day earlier were initially found by search and rescue officials at 10:14 a.m. local time in a mountainous area near Hokuto City.
This led police, firefighters and SDF personnel to begin intensively searching the vicinity where the wreckage was found as this was believed to be near the crash site.
SDF helicopters also located what was believed to be part of the missing plane on the east side of Mt. Hakamagoshi, which confirmed the likelihood the plane went down in this region.
The plane with four crew members on board disappeared from radar on Monday morning in the southern part of Hokkaido, in Japan's northernmost prefecture, the defense ministry here said.
There were four male crew members on board the plane when it lost contact with a ground controller at around 11:50 a.m. local time, according to the defense ministry.
The four members included a pilot, a backup pilot and two mechanics, the ministry said.
The LR-2 reconnaissance plane took off in poor weather from Okadama Airport in Sapporo City at about 11:20 a.m. on Monday.
The light plane was heading for Hakodate Airport in the same prefecture and lost communications with air traffic controllers at around 11:50 a.m.
The plane disappeared from radar about 30 km west of Hakodate Airport, the defense ministry said.
It was last seen flying at an altitude of 900 meters and was preparing to make an instrument landing due to low visibility.
The jet belongs to the GSDF Northern Territory Air Force in Sapporo City and was scheduled to transport a patient from a Hakodate hospital.
The twin prop plane is 14 meters in length and has a 10 person capacity. A stretcher for transporting emergency patients is installed in the aircraft, and the plane is also used for reconnaissance missions by the GSDF.
GSDF officials and firefighters are looking into the cause of the accident and had initially deployed around 1,800 people including the SDF, police and fire and rescue workers to continue searching for the aircraft on Tuesday.
Search efforts were hampered however by poor weather, including rain and fog, which meant that aerial searches had to be called off.
Japan's Meteorological Agency had said their was light rain and cloud in the area and there was a low atmospheric pressure in the area when the plane went missing.
The JMA also said that due to a cold westerly front coming in the atmospheric pressure in the area the plane was flying in could have become unstable.