What happened
On 21 September 2015, a Dasslamt Falcon 20D, registration G-FRAR, was conducting an aerial work mission involving target towing for a warship in the Lyme Bay area. While flying at 1,700 ft, the aircraft was towing a target approximately 23,000 ft behind the plane. During a live-firing exercise, the target was struck, causing the aircraft to yaw and subsequently lurch to the left, likely due to the target hitting the sea surface.
Recognizing that the target had become unstable, the Target Tow Operator (TTO) activated the primary cable cutter. Although the cable was intended to release, a 10-meter section remained attached to the aircraft. The pilot felt vibrations through the airframe and rudder pedals, while the TTO observed the remaining cable "corkscrewing" behind the aircraft. Despite an attempt by the pilot monitoring to use the secondary cockpit cutter, the cable remained attached.
The crew declared an emergency and elected to land at Bournemouth. To reduce the risk of the cable interfering with flight controls, the crew landed with the flaps up. During the approach, the cable stopped striking the airframe. Upon landing, it was discovered that one end of the cable had looped around the underwing winch, while the other end had become lodged in the gap between the elevator and the horizontal tailplane, causing minor damage to the tailplane surface.
The investigation
The investigation examined the mechanics of the cable separation and the state of the aircraft's winch and tailplane. The crew reported no injuries, and the aircraft landed safely. Investigators found that the 10-meter segment of cable had separated at both ends. One end had a cut consistent with the use of the cable cutter, while the trailing end likely failed due to an overload after the target was hit.
Post-flight inspection revealed that the cable had snagged on the winch mechanism and that the trailing end had become wedged in the horizontal tailplane. Crucially, there was no evidence that the cable had restricted the movement or effectiveness of the elevator during the flight.