A MISSING emergency battery could have contributed to the crash landing of a former military plane in a field near Witheridge last year, a report has concluded.

The report by the Air Accident Investigation Branch (AAIB) explained how a serving military fast jet pilot and his student both walked away from the jet's 115-mile-per-hour emergency landing.

The BAC 167 Strikemaster plane came down in a field near Foxdon Farm between Witheridge and Nomansland on Sunday, April 26 2009.

The report said that after take off a 40-minute instructional session was flown, during which all the aircraft systems operated normally.

As the weather was not suitable for aerobatics, the pilot headed back to Exeter International Airport. On the way back the pilot noticed the aircraft slowing.

Attempts to restart the plane's engine were unsuccessful and the pilot initiated an emergency landing towards an open field.

The report said: "The aircraft did not appear to slow down on the wet grass surface as much as the instructor had expected. He helped the student to place his hands in a brace position. However, this resulted in the instructor not being properly braced when the aircraft impacted with an earth bank with a hedge on top.

The aircraft struck the bank at 50 knots, around 57mph, and came to a rapid stop. The lack of bracing contributed to the instructor's back injury.

The student sustained a minor injury. When the jet came to a standstill the instructor and student got out of the plane and walked to a nearby farmhouse for help.

The emergency services arrived shortly after and both pilots returned to Exeter Airport.

The AAIB concluded that, although the cause of the engine run-down was not established, the loss of electrical power from the two main batteries and absence of an emergency battery meant that the engine could not be restarted.

The report said: "The aircraft was designed to be operated with an emergency battery and had it been installed, it would have allowed the pilot the opportunity to attempt a re-light of the engine."

The report said that the instructor demonstrated a pre-flight inspection to his student and noted there was not an emergency battery.

Checks were made to see if an emergency battery was required for the flight and the instructor was informed that it wasn't.

The report added: "The Civil Aviation Authority subsequently investigated the UK fleet of Strikemaster aircraft and concluded that all the remaining aircraft of this type on the UK register had an emergency or third battery fitted in accordance with the approved configuration."