PNG report details Twin Otter’s loss of nose wheel during take-off
By Andrew Curran.
Papua New Guinea’s Accident Investigation Commission (AIC) has identified slippery runway conditions, inadequate drainage and the impact with an airstrip perimeter fence as key factors in an accident involving a Tropicair DHC-6-300 Twin Otter that lost its nose wheel during take-off from Tapini in January.
The final report, released on October 27, 2026, found that the aircraft lost directional control while departing Tapini (TPI) in Central Province on January 22. The Twin Otter, registered P2-BBM (msn 542), veered off the left side of the runway and struck the perimeter fence before becoming airborne with its nose wheel assembly damaged.
The aircraft continued to Port Moresby, where the crew conducted an emergency landing without the nose wheel and lower fork assembly. All 21 occupants, comprising two pilots and 19 passengers, escaped injury.
The investigation found that the landing gear failure resulted from a combination of structural loading during the runway excursion, entanglement with perimeter fencing wire and subsequent overload. Investigators found no evidence of pre-existing fatigue cracking, corrosion, manufacturing defects or prior damage to the affected components.
Loss of directional control on take-off
The aircraft was conducting an instrument flight rules (IFR) charter return flight to Port Moresby (POM). The crew had landed at Tapini earlier that morning and reported observing wet and muddy runway conditions during the approach.
According to the report, local residents told the crew that heavy rain had fallen overnight. The runway grass had recently been cut, and investigators later observed tractor tyre marks and disturbed grass and soil along the aircraft’s ground track.
Tapini’s 915-metre grassed red-clay airstrip has a 4.5% downhill gradient towards the east. Its operating guidance warns that the surface can become very slippery after rain and specifies that landings are to be made on Runway 27, with take-offs using Runway 09.
The crew parked at the western end of the airstrip and prepared for the return flight. To reduce the risk of the aircraft sliding downhill, the pilots positioned it perpendicular to the runway before commencing a rolling take-off.
The report says the aircraft began sliding forward as the pilot-in-command (PIC) turned onto the runway heading. He applied take-off power and attempted to maintain directional control as the aircraft accelerated.
Recorded flight data and video evidence showed the aircraft initially yawing to the right, then overshooting the runway heading and tracking towards the left edge of the strip. The PIC applied corrective inputs involving rudder, nose wheel steering and asymmetric engine power, but the aircraft continued towards the runway perimeter.
The aircraft left the prepared runway surface and entered overgrown vegetation before striking the perimeter fence. It subsequently turned back towards the runway and became airborne.
The flight path of the Tropicair Twin Otter from Tapini to Port Moresby
Fence wire contributed to landing gear separation
The AIC determined that the nose wheel assembly was subjected to substantial loading as the aircraft skidded across the low-friction surface and the crew attempted to regain directional control.
During the excursion, the nose wheel assembly snagged barbed and mesh wire from the perimeter fence. The wire became wrapped around the remaining nose landing gear structure, while approximately 16 metres of barbed wire remained entangled with the right main landing gear during the flight to Port Moresby.
Investigators considered it highly likely that the right main wheel subsequently ran over trailing fence wire, applying an additional tensile load to the nose wheel assembly.
The combined loading caused fractures in the nose wheel fork. The remaining material failed shortly after lift-off, allowing the nose wheel and lower fork assembly to separate from the aircraft.
A material examination conducted with assistance from the Australian Transport Safety Bureau (ATSB) found predominantly ductile overstress fractures. The examination found no evidence of fatigue cracking or pre-existing or manufacturing defects that might have contributed to the failure.
The aircraft continued to Port Moresby after the crew were advised during the cruise that the nose wheel assembly had separated. The pilots requested a visual inspection from the control tower before landing.
After assessing the aircraft’s configuration, the crew declared a PAN PAN and requested emergency services to stand by. The aircraft landed on Runway 32L at Port Moresby Airport and slid approximately 87 metres on the exposed lower nose landing gear structure before coming to a stop. The landing caused further substantial damage to the remaining nose landing gear components.
Grass and wire wrapped around the right landing gear of the Tropicair Twin Otter after landing at Port Moresby. Photo: PNGAIC.
Investigators identify interacting factors
The AIC attributed the accident to a combination of environmental, aerodrome and human factors.
The wet, muddy runway surface had significantly reduced tyre traction, braking effectiveness and steering control. Investigators found that inadequate drainage allowed water to accumulate on the strip, while the downhill gradient and lateral slope of Runway 09 increased the aircraft’s tendency to slide.
The vegetation and perimeter fence alongside the runway also increased the likelihood and severity of damage once the aircraft departed the prepared surface.
The report also identified limitations in the runway information available to the crew before departure from Port Moresby. Information obtained through the operator’s ground personnel was generally limited to weather conditions and did not include a structured assessment of runway surface conditions or braking action.
The AIC found that the absence of a formal runway condition assessment increased the operational risk of conducting a take-off from the contaminated surface.
The investigation also examined the PIC’s use of the nose wheel steering tiller during the take-off roll. The aircraft manufacturer and Tropicair’s procedures caution against using the tiller for directional control during take-off, when control is expected to transition towards aerodynamic rudder effectiveness as airspeed increases.
However, investigators considered the PIC’s use of the tiller an instinctive response to an unexpected and rapidly developing loss of control, rather than a deliberate departure from standard operating procedures.
The report noted that the aircraft began sliding almost immediately after brake release and power application, leaving the pilot little time to respond. Low tyre-to-surface friction also reduced the effectiveness of steering inputs.
The AIC concluded that the tiller use did not initiate the runway excursion or restore directional control. The investigation instead found that the aircraft’s recovery towards the runway heading was highly likely to have resulted from increasing rudder effectiveness as its speed increased.
The report found that both pilots were licensed, qualified and medically fit for the flight. The aircraft had a valid Certificate of Airworthiness, its maintenance records showed no outstanding scheduled maintenance or recorded defects, and its weight and centre of gravity were within approved limits. Investigators found no aircraft defect or malfunction that contributed to the occurrence.
Vegetation found lodged in the wing tip of the Tropicair Twin Otter after landing at Port Moresby. Photo: PNGAIC.
Tropicair implements safety measures
Tropicair provided the AIC with evidence of safety actions undertaken voluntarily after the accident. The operator reported the measures to investigators on May 13, 2026.
The actions included:
- Completing a risk assessment of operations at Tapini Airstrip.
- Developing and delivering training for the local agent in weather observation and runway condition reporting.
- Installing a rain gauge at Tapini to improve local weather observations.
- Reviewing and updating the operator’s Route Guide and procedures for operating into wet and sloping remote airstrips.
- Clearing the airstrip’s drainage system and vegetation along runway edges to improve drainage and reduce water accumulation.
The report identifies these as actions taken voluntarily by the operator, rather than formal safety recommendations issued by the AIC.
The investigation also noted that the aircraft’s Quick Reference Handbook and Pilot’s Operating Handbook did not contain procedures for an emergency landing following the loss of the nose wheel assembly.
The AIC’s stated objective was to identify safety issues and reduce the likelihood of similar accidents, rather than apportion blame or liability.
You can read the final report here.
Photos: PNGAIC
Contact the writer: andrew@aerosouthpacific.com