What happened
On 15 May 2002, a Partenavia P68B, registration ZK-ZSP, was conducting a scheduled air transport flight from Gisborne to Napier. While flying at 5,000 feet in instrument meteorological conditions near Wairoa, the aircraft's right engine lost power. The pilot, carrying four passengers, initially attempted to manage the descent but found the aircraft unstable and difficult to control.
During the emergency, the pilot attempted to use the fuel selector to crossfeed, but encountered significant difficulty. The pilot mistakenly selected the wrong valve, causing the left engine to vibrate before power could be restored. Unable to maintain altitude with the windmilling propeller, the aircraft descended through the cloud layer. The pilot eventually executed a successful landing on a metalled road near the coastline. There were no injuries and the aircraft sustained no damage.
The investigation
TAIC investigators examined the fuel system and the circumstances leading to the power loss. The investigation established that while sufficient fuel was available on board, it was not being delivered to the right engine. The inquiry focused on the mechanical state of the fuel selector knobs and the synchronization between the cockpit controls and the wing valves. Additionally, the investigation reviewed the pilot's actions during the emergency and the adequacy of the aircrew licensing examination system regarding the ability to process complex information under stress.
Findings
- The right engine lost power due to fuel starvation caused by an inadvertent transfer of fuel from the right tank to the left tank.
- A loss of synchronization existed between the cockpit fuel selector knob placards and the actual position of the fuel selector valves.
- The cockpit fuel selector knobs were notably stiff, which prevented the pilot from quickly and effectively managing the fuel system during the emergency.
- The pilot's management of the fuel system and the failure to feather the propeller contributed to the inability to maintain altitude.
- The investigation noted that the pilot's performance was hindered by the high stress of the situation and an inability to adequately process information during the crisis.