Case 3: United Aviation, freight trip, June 11, 1997

Dead: Pilot Timothy Thompson

The Transport Accident Investigation Commission (TAIC) report tells how in the early hours of June 11, 1997, the twin-engine aeroplane taking freight through the night from Palmerston North to Christchurch disappeared from radar.

The aircraft wreckage and Thompson's body were subsequently found in the Tararua ranges, 21km southeast of Paraparaumu.

The aircraft had probably encountered severe in-flight icing at 10,000 feet (3050m), resulting in loss of control.

Carbon monoxide from a faulty heater had got into the cabin and was thought to have impaired Thompson's mental functioning.

"Factors contributing to the accident included a flawed operational environment and inadequate flight planning by the pilot to minimise the exposure to icing conditions and the lack of an appropriate safety culture within the operating company."

A log of CAA audits shows non-compliance issues over a number of years but certification was renewed regardless.

Concerns ranged from pilot training to maintenance, but the airline was not shut down until after the accident.

The report says: "From the results of the years of audits, the repeated examples of non-compliances and non-conformances ... it was evident that United Aviation had a deficient safety culture and had forfeited the right to participate in the aviation industry."

"The CAA's apparent failure to take appropriate action ... contributed to the accident."