A former Civil Aviation Authority safety manager told police that when he forged an email which was presented to an air crash inquest, he saw himself as a whistle blower.
Peter Kirker is on trial in the Wellington District Court for forgery and attempting to pervert the course of justice.
He is accused of sending emails to those involved in an inquest into a fatal air crash over Paraparaumu in 2008, which purported to be from an aviation expert, Frank Sharpe.
The emails raised concerns about events on the day of the crash.
In a recorded interview Mr Kirker told a detective he attended the scene on the day of the crash, but the next day the Transport Accident Investigation Commission took over the inquiry.
Mr Kirker said he was asked to review the TAIC report after concerns were raised by the family of one of the dead and his computer modelling revealed it was unlikely either pilot saw the other aircraft before the collision.
However he said TAIC stood by its report and he felt that agency and the CAA might be joining forces to prevent the coroner learning the true facts relating to the crash
Mr Kirker said he believed the CAA wanted to minimise any damage to its reputation.
A police investigation revealed Mr Sharpe had not sent the emails and Mr Kirker resigned from his position at the CAA after his arrest.