Aircraft

Norwegian investigators have confirmed that a lightning strike, which severely damaged the tail of a Kato Airline Dornier 228-200, caused the aircraft to crash while attempting to land at Bodo airport during a storm.

Both pilots and the two passengers on board were injured when the turboprop, operating domestic flight 603 from Rost on 4 December 2003, struck the ground heavily just short of Bodo's runway.

Thunderstorms had been in the vicinity during the approach and Norway's accident investigation board, the AIBN, says the aircraft suffered a powerful lightning strike to the nose, which passed to the empennage and severed the central elevator control rod.

The AIBN says it destroyed the only connection between the pilots' control columns and the elevator, adding: "When the lightning struck the aircraft the pilots were blinded for approximately 30s. They lost control of the aircraft for a period and the aircraft came very close to stalling."

Despite the damage, the pilots used the elevator pitch-trim to regain a degree of control of the aircraft and attempt a landing. The aircraft's airspeed on the first approach was too high, however, and the aircraft bounced the crew aborted the landing and took the turboprop around for a second approach.

"Wind conditions were difficult and the next attempt was also unstable in terms of height and speed," says the AIBN. "At short final the aircraft nosed down and the pilots barely managed to flare a little before the aircraft hit the ground."

It says that the aircraft struck the ground 22m (72ft) short of the eastern end of runway 25 and slid 78m before coming to a halt. The heavy impact, around 8.4g, crushed the underside of the fuselage and damaged the propellers. The aircraft, a 16-year-old example registered LN-HTA, was written off.

"There is reason to believe that the total amount of energy in the lightning exceeded the values of the construction specifications," says the AIBN, although it points out that up to 30% of the wiring in bonding connectors in the tail may have been defective before the strike.

In its report into the accident the AIBN has made three recommendations, centred on increased attention to maintenance, better use of airborne weather radar, and improved presentation of ground weather-radar information by air traffic control.