A Russian army Mil Mi-28N attack helicopter crashed during firing trials on a range near Moscow on 19 June, representing the first loss involving the type.
The cause of the accident has not yet been confirmed, but is thought to be related to a loss of power following gas ingestion during rocket firing, according to a report by the Kommersant newspaper. An investigation by the Russian defence ministry is under way.
The helicopter was firing unguided rockets from a low hover of around 130ft (40m) when it suddenly lost power and landed heavily. Its tail rotor and pylon were destroyed in the crash, but both aircrew survived and left the aircraft unassisted.
© S Soldatkin/Rostvertol
A Rostvertol engineer quoted by Kommersant confirmed the incident as technical in origin, but would not specify the cause. Another source said the cause was "not connected to the main part of the helicopter".
According to a military source also quoted, the fault lay with the Mi-28's fire-control system, which launched the rockets under unsuitable parameters when the crew had intended to fire the aircraft's 30mm nose-mounted cannon.
A source in state holding company Russian Helicopters says: "A final resolution on the causes of the crash and possible repair of the machine will occur only after the completion of work by the accident commission." The helicopter remains at the firing range.