On 9 August 2011, a Piper Aircraft Corp PA-44-180 aircraft, registered VH-FRI departed Bankstown for Coffs Harbour, New South Wales, on a private instrument flight rules (IFR) flight. About 30 NM to the north-west of Port Macquarie, the pilot decided to divert to Port Macquarie aerodrome due to a build-up of cloud above the forecast freezing level along the intended flight path.
While the pilot was examining arrival charts for the approach into Port Macquarie, he inadvertently entered cloud. The electronic flight instrument system (EFIS) screen went blank, some of the analogue instruments became fixed in position and the autopilot disconnected.
The pilot followed the standby attitude indicator and set an attitude and power setting to estimate an appropriate rate of descent.
The pilot broadcast a PAN call and requested assistance from Air Traffic Control. The controller acknowledged the PAN call and confirmed the aircraft's position. The aircraft then tracked away from Port Macquarie aerodrome. The controller queried the pilot's intentions, but did not inform the pilot of the aircraft's changed flight direction.
The pilot again asked for assistance, and the controller suggested a heading change. A short time later, the pilot became visual with the ground and was able to navigate the aircraft to Port Macquarie. He noticed that there was light icing on the leading edge of the wings.
Subsequent engineering tests revealed that the pitot heat had only one of two heating elements fitted. A second element was subsequently fitted.
The operator has directed their contract maintenance organisations to ensure that both heating elements are fitted and serviceable prior to certifying the aeroplane airworthy. An undertaking to educate flight crew on the correct technique for checking that both heating elements are operating when conducting a pitot heat check was also made.