The fatal crash involving a Japanese Army (Japanese Ground Self-Defense Force) AH-64D attack Helicopter into a residential area on Monday, was indeed due to a improper routine maintenance prior to the flight.
Japanese Defense Ministry said the helicopter was on a test flight, following replacement of its main rotor hub, which connects the four rotor blades to the gearbox output shaft.
During the test flight, the main rotor got detached from the helicopter possibly due to the faulty maintenance, nose diving the copter into the residential area.
The Apache had taken off from GSDF Metabaru Camp at 4:35 p.m. Monday and flew about 6 kilometers before crashing into the two-story house in Kanzaki city in Saga prefecture, seven minutes later.
The main rotor heads of AH-64D helicopters need to be replaced after every 1,750 hours of flight time.
The two crew members on board the helicopter were killed in the accident.