Military officials blamed mechanical failure for the crash of an Apache attack helicopter in Megara, west of Athens, that killed both pilots on board.

The army helicopter had been conducting a training flight after taking off from a base at Megara when the accident occurred. Authorities believe that the aircraft suffered a serious problem, possibly involving a fire breaking out, at 3,000 feet. The pilots attempted to conduct an emergency landing but are believed to have lost control of the helicopter about 100 feet in the air, as it then went into a nosedive and hit the ground.

The pilot, an experienced handler of Apache helicopters, and his co-pilot were killed instantly. They had not been named by last night.

President Karolos Papoulias expressed his “deep sadness” at the deaths, while Defense Minister Evangelos Venizelos described the death of the two officers as “tragic” and promised that the state would support their families.

Venizelos also said that a military prosecutor would launch an immediate investigation into the causes of the crash. One of the key elements of the probe is likely to be why such a new helicopter (the Apache had only been in use since February) should suffer a mechanical failure. Authorities said that the aircraft had been properly serviced before the training flight.

The Apache was one of 12 that Greece originally ordered in 2003. The aircraft were delivered in 2007 but were placed in storage until 2009, as there were some doubts about their reliability, which Greece wanted to resolve with their manufacturer. During this two-year period, it was claimed that rats had gnawed through the helicopters’ wiring but military authorities denied this. The helicopters were given to the army in 2009 but were not used until this year.