What happened
On 18 January 1998, a Jetstream 4100, registration G-MAJA, was performing a scheduled public transport flight from Cardiff to Jersey. While descending through 6,000 feet in moderate rain and temperatures of +2°C, the aircraft experienced a bright flash and a loud bang. The event occurred near the north-eastern corner of Sark.
Immediately following the strike, the right engine generator failed, and a warning indicated an overheat in the left engine. The crew responded by resetting the generator and following established checklists for the overheat warning. As a precaution against potential structural damage, the pilot reduced the airspeed to 140 kt. During the subsequent approach to Jersey, the pilot noted that aileron control felt less effective than usual, though this may have been due to turbulence and wind conditions. There were no injuries to the 3 crew members or 12 passengers on board.
Upon landing, the crew identified several areas of damage, including structural damage to the fin and the right aileron, as well as small punctures in the pressure hull skin near the nose. The strike also rendered the propeller de-icing and fire-detection systems inoperative.
The investigation
Investigators analyzed radar recordings and air traffic control transcripts, which confirmed changes in the aircraft's descent rate, heading, and ground speed consistent with a strike occurring approximately 30 seconds before the pilot's radio report.
Data from the Meteorological Office was reviewed to determine nearby lightning activity. While the aircraft's lightning detection system showed no immediate threats, and the nearest recorded discharges were at least 70 nautical miles away, broader meteorological maps indicated a high concentration of lightning activity in the Channel Islands and Cherbourg Peninsula region during the preceding hour.
Findings
- The lightning strike likely occurred when the aircraft's passage triggered a low-power discharge in an area where residual lightning potential remained.
- The aircraft's lightning detection system is historical rather than predictive, meaning it cannot provide guidance to avoid isolated strikes that occur as an aircraft enters a previously clear area.
- The strike caused structural damage to the vertical fin, right aileron, and the forward pressure hull, and disabled specific de-icing and fire-detection systems.