Engineer reveals fresh theory on Air Adventures disaster

The dramatic final day of the inquest into the Air Adventures plane crash has thrown up a new theory for the cause of the accident.

Evidence yesterday revealed the pilot had wrongly programmed his Global Positioning System (GPS), setting his aircraft containing eight passengers on a crash path.

Investigators have always struggled to explain why pilot Michael Bannerman descended on the correct angle for a safe landing, but started his descent too soon so that he crashed short of the Christchurch Airport runway.

The Transport Accident Investigation Commission (TAIC) investigation report, released in March, makes a brief one-paragraph mention of the aircraft's two GPS systems, but appears to dismiss any suggestion the GPS systems may have played a role in the crash.

However, at the inquest this week questions have been raised over the data extracted from the GPS, which was mounted on the dashboard directly in front of Bannerman.

Dr Ian Huntsman, an aeronautical engineer, who was the partner of crash victim Katherine Carman, raised questions over the GPS data earlier this week and prepared a report at the coroner's request.

Dr Huntsman concluded it was "no coincidence" that the crash site was 2.3km short of the runway when GPS data showed there was a discrepancy of about 2km between the aircraft's point of impact and the safe landing point.

He said he believed Mr Bannerman had been illegally using his GPS pilot as his main navigational tool and looking out the window to get his bearings before the crash.

Mr Bannerman was inexperienced in instrument flying and would have felt more comfortable using the GPS pilot with an occasional glance at the altimeter.

Although it was only a theory, it appeared to explain why Mr Bannerman flew the track revealed by other data.

If Mr Bannerman had wanted to correctly use his GPS to help his landing, he should have set his "waypoint" (destination) at the same point as a beacon normally used in the procedure.

The police have endorsed Dr Huntsman's report, and coroner Richard McElrea has asked for a further expert police analysis to be added to Dr Huntsman's evidence.

Dr Huntsman told the Press last night it was surprising such vital evidence was left until the final day of the hearing for discussion.

He emphasised his reading of the crash was yet another theory, but it had received support from the coroner's aviation expert.

TAIC investigator John Goddard said last night he was aware of the way the GPS had been programmed, but Mr Bannerman may have had personal reasons for selecting the settings he was using. It could have been used to pinpoint his office or other positions, he said.

In addition, it was not possible to say what the GPS screen was showing. The GPS information was not hard fact and could not therefore be used to construct a theory.

A written decision is expected later next year.

- NZPA