A multimillion-pound drone was scrapped after it crashed at a Ceredigion airfield, according to a declassified report.
The 70st (450kg) unarmed, unmanned air vehicle (UAV) crashed at Aberporth airfield during a test flight in October 2014.
It was part of the Army’s £1.16bn Watchkeeper surveillance drone programme – due to come online in 2017.
Details of the crash emerged in a Ministry of Defence (MoD) report.
The drone in this case was being flown by civilian contractors from UAV Tactical Systems Ltd, with the crew including two experienced former RAF pilots.
Weather conditions began to deteriorate after the drone had flown a circuit of the west Wales drone testing area at 5,000ft (1,524m).
Those flying the UAV tried to override its automatic landing system as it came in to touch down because they were worried it would fly into a thunderstorm.
Improve safety
Witnesses described how the Watchkeeper suddenly plunged nose-down from an altitude of about 10-15 feet (3-4.5m), before skidding along the runway.
It had only flown for 13 hours before the accident and was scrapped due to the damage.
An investigation report found the UAV’s software falsely detected a landing when the aircraft was still in the air.
A total of 26 recommendations were made to improve safety, including changes to the approach routes at Aberporth.
The MoD’s Watchkeeper programme, which aims to provide the Army with a tactical drone, has faced a series of major setbacks and delays.
Contracts were awarded in 2005 to buy 54 UAVs but many have remained in storage and there is a shortage of flight crews.
Unlike the RAF’s Reaper drones, which carry weapons, the Watchkeeper surveillance UAVs are designed to be operated by Royal Artillery crews with no previous flying experience.
The MoD said the Watchkeepers should reach full operational capability during the middle of 2017.