What happened
On 15 December 2018, an MBB-BK 117 D-2 EC145, registration G-HEMC, was conducting a Helicopter Emergency Medical Service (HEMS) mission near Hollesley, Suffolk. The flight was operating at night to transport a patient to a hospital. After an initial approach to a large field, the crew received a request from the medical team on the ground to move the aircraft to a different landing spot within the same field to facilitate patient loading.
Prior to the move, the crew performed a ground reconnaissance. One pilot inspected the area on foot using a high-powered torch, identifying some wires near an adjacent road. The crew also consulted an electronic map, which displayed powerline locations but lacked data for telegraph lines. During the repositioning taxi, the pilot used the aircraft's landing light to scan for obstacles. As the aircraft attempted to touchdown at the new site, the pilot noted a sensation of instability, prompting a brief repositioning before the engines were shut down.
Upon exiting the aircraft, the commander discovered a single telegraph wire hooked onto the rear radio antenna. The wire had been pulled from a post located in the field, which had remained undetected during both the aerial and ground inspections.
The investigation
The AAIB investigation focused on how the wire escaped detection during the safety checks. The investigators examined the ground reconnaissance process, the use of the electronic mapping system, and the physical state of the aircraft and the wire. A subsequent inspection of G-HElamc at its base revealed no structural damage or impact marks. The wire itself remained intact following the contact.
Findings
- The crew performed both an aerial assessment and a manual ground inspection with a torch prior to the repositioning.
- The electronic map used by the crew included powerline overlays but did not contain information regarding telegraph lines.
- The telegraph wire was pulled from a post that was not identified during the initial obstacle checks.
- No damage was sustained by the aircraft or the wire during the incident.