Introduction
On 7 April 2023, a Piper Aircraft Corporation PA-31-350 Chieftain (registration VH-HJE), operated by Air Link, was conducting a freight charter flight from Archerfield, Queensland. The flight was planned with an intermediate stop at Bankstown, New South Wales, before returning to Archerfield, and was conducted under instrument flight rules at night.
Flight Details
The aircraft departed Archerfield at approximately 0024 local time. During the first leg to Bankstown, the pilot reported an intermittent fault with the autopilot, producing uncommanded pitch changes and rates of climb and descent around 1,000 ft/min. Consequently, much of the first leg was flown manually. After landing at Bankstown at about 0248, a defect entry was made on the maintenance release. The pilot, confident in hand-flying, elected to continue. The aircraft was refueled to maximum capacity, and a small quantity of water detected in fuel samples from both main tanks was drained until clear. The freight for the return leg was a light load, and weight and balance were within limits.
Autopilot Issue and Refueling
After takeoff at 0351, the pilot climbed to 9,000 ft, then changed both fuel selectors from main to auxiliary tanks. During cruise, engaging the autopilot resulted in continued uncommanded pitch events, so the pilot did not use it for part of the flight. Approaching top of descent, the pilot conducted normal flow checks by memory and completed other tasks (radio frequency change, weather check, arrival briefing). The pilot later recalled switching from auxiliary back to main tanks, using fuel quantity gauges to confirm. The pilot calculated 11 minutes of fuel remained in auxiliary tanks (estimated 177 L in each main).
Fuel Starvation and Engine Power Loss
Around eight minutes after commencing descent, at 0552 and 28 NM south of Archerfield, the right ‘low fuel flow’ warning light illuminated, followed by a slight reduction in right engine noise. ADS-B data showed moderate deceleration and deviation right of track. The pilot noted only minor yaw requiring small rudder input after disconnecting autopilot. Over the next minutes, the pilot troubleshooted: switched on emergency fuel boost pumps, advanced mixture to RICH, cycled throttle, moved right fuel selector to auxiliary, disengaged autopilot, and retrimmed. No change. The pilot then conducted the engine roughness checklist. Oil temperature, pressure, and cylinder head temperature were normal; MAP dropped from 31 to 27 inHg; EGT in green range; fuel flow zero. Unable to rule out fuel contamination, the pilot did not reselect main tank. Assessing partial power loss, the pilot decided not to shut down and feather the propeller. At 0556, at about 3,300 ft and 20 NM south of Archerfield, the pilot advised ATC of an engine malfunction and requested to maintain altitude. With maximum power on the left engine, the aircraft descended at 100 ft/min. The pilot calculated they could reach Archerfield and did not declare an emergency.
At 0602, about 12 minutes after the right engine failure, the left engine began running rough, and the left low fuel flow warning light illuminated. Severe rough running and surging caused pronounced yawing. The pilot switched the left engine’s fuel supply to the auxiliary tank but did not change back to mains. With both engines malfunctioning and propellers unfeathered, descent rate increased to about 1,500 ft/min. The pilot then focused on finding a forced landing site. ADS-B data showed the aircraft at about 1,600 ft when the left engine failed. The pilot aimed to stay above minimum control speed (72 kt). Ground speed fluctuated from 110 to 75 kt, yielding approximately 71 kt indicated airspeed, equal to clean stall speed. The pilot declared an emergency and advised ATC of an off-airport forced landing.
Forced Landing
With limited suitable areas, the pilot left flaps and gear retracted to minimize drag. At about 0605, the aircraft touched down in a rail corridor beside the railway line. The left wing struck a wire fence, and the aircraft hit several trees, sustaining substantial fuselage and wing damage. The pilot received minor injuries and exited through the rear door.