What happened
The aircraft, registration G-UESS, a private aircraft type (unspecified model), began its journey from Biggin Hill, U.K., traveling to Paris-Le Bourget. After picking up additional passengers in France, the flight proceeded to Liverpool, where it was refueled with turbine fuel containing an anti-icing additive. The final leg of the flight departed Liverpool for Stornowably, Scotland, carrying a pilot, a pilot's assistant, and several passengers including infants.
During the flight, the aircraft was operating under Instrument Flight Rules (IFR) at Flight Level 310. While near Dean Cross, the crew established radio contact with the pilot of another aircraft, registration N40GS, which was a Citation 11. Both aircraft were traveling toward Stornoway and maintained intermittent communication on a private frequency. Air traffic controllers directed both planes to specific headings and altitudes to maintain separation during their descent.
As the aircraft approached Stornoway, the pilot reported having N40GS in sight and requested permission to continue his descent. The controller cleared the aircraft to descend at the pilot's discretion. However, shortly after 17:40 hrs, communication with the aircraft ceased. At 17:51 hrs, Stornoway controllers officially reported a loss of contact.
A search operation later recovered 6 fatalities near the last known radar position, including the pilot, assistant, and passengers. While the wreckage was not fully recovered, several bodies were retrieved from the sea over several months.
Findings
The investigation concluded that the primary cause of the accident was the pilot's lack of awareness regarding his actual altitude, which led to the aircraft descending into the sea. This error was compounded by the pilot being distracted by efforts to maintain visual contact with the other aircraft and being deceived by ground lights that provided false visual cues during the descent.