A report has found that the world's largest airship crashed during a test flight in Bedfordshire last August because its mooring line got caught on power lines.
The Air Accidents Investigation Branch say the Airlander 10 was climbing to an excessive height at Cardington Airfield when it happened.
Ground crew told the pilot that the line was around 50ft (15 metres) long but it was actually 155ft (47 metres).
As the aircraft approached its second landing the rope became entangled in power lines near the boundary of the airfield.
The AAIB report said although the aircraft escaped the wires, "the encounter contributed to a high final approach". Airlander 10 arrived over the landing site at around 180 feet and was "reluctant to descend naturally".
The pilot manoeuvred the aircraft to a nose-down position at an angle of around 10 degrees in a bid to bring its mooring line within reach of the ground crew. But the aircraft "suddenly pitched further down to about 18 degrees and started to descend.
Airlander 10's cockpit took the brunt of the impact but no-one was injured.
- Carry 10 tonnes
- Is 92 metres long
- 44 metres wide
- 26 metres high
- travels at 92mph
- 15 metres longer than biggest passenger jet
The Airlander 10, so named because it can carry 10 tonnes and is about 50ft (15 metres) longer than the biggest passenger jets and uses helium to become airborne. The manufacturer claims it could be used for a variety of functions, such as surveillance, communications, delivering aid and even passenger travel.