Airlander 10 crash-landed after mooring line snagged power cables
The world's longest aircraft - the £25m Airlander 10 - crash-landed after climbing to an excessive height because its mooring line became caught on power cables, a report has found.
The 302ft (92m) long aircraft, which is part plane and part airship, nosedived after a test flight at Cardington Airfield in Bedfordshire on 24 August.
The Air Accidents Investigation Branch said the line was hanging free after a first landing attempt had failed.
No-one was injured in the accident.
At the time of the incident, Airlander's developer, Hybrid Air Vehicles (HAV), said the craft had "experienced a heavy landing and the front of the flight deck sustained some damage".
The crew, however, were "safe and well".
The AAIB report into the incident stated that ground crew had told Airlander's pilot the mooring line was about 50ft (15m) long, but it was in fact 155ft (47m).
The rope became entangled in power lines near the airfield as the pilot attempted a second landing.
"The encounter contributed to a high final approach", investigators said.
The craft was about 180ft (55m) over the landing site and was "reluctant to descend naturally".
The pilot attempted to manoeuvre the aircraft to a nose-down position to bring its mooring line within reach of the ground crew but it "suddenly pitched further down to about 18 degrees and started to descend," the report stated.
"There was insufficient height in which to affect a full recovery and the aircraft struck the ground."
Repairs were carried out on the cockpit and earlier this week HAV said these were complete and Airlander was undergoing "an extensive test phase prior to its next flight".
A new landing system, which will allow it to return to ground from a greater range of angles, and a redesign to allow easier recovery of the mooring line, are among changes that have been made since the crash, the company said.
Airlander 10 in numbers
- 44,100 lbs (20,000kg): The weight of the airship
- 20,000ft (6,100m): The altitude it can reach
- 80 knots (148km/h): Maximum speed
- 5 days: How long it can stay airborne during manned flights
- 22,050 lbs (10,000kg): Total payload - the weight the ship is able to carry