What happened
On 24 March 2000, a charter flight operated by Airwork (NZ) Limited arrived at Taupo Aerodrome for landing. The aircraft, a Piper PA31T3-T1040 with registration ZK-FPL, was carrying one pilot and 10 passengers.
During the approach, the pilot observed several tandem parachutists descending near the runway. To avoid creating unnecessary drag that might hinder any necessary maneuvering to avoid the parachutists, the pilot made a conscious decision to delay lowering the undercarriage. The intention was to complete this checklist item once the runway was confirmed clear. However, as the aircraft continued its approach, the pilot remained focused on monitoring the progress of the parachutists.
As the aircraft crossed the runway threshold and the pilot reduced power for the landing flare, an undercarriage unsafe warning horn activated. In an attempt to execute a go-around, the aircraft's propellers struck the runway, and the cargo pod settled onto the pavement. The aircraft slid along the runway and eventually veered onto the grass. While the impact caused substantial damage to the aircraft, including the destruction of the propellers and cargo pod, there were no injuries to the 11 people on board.
The investigation
The investigation examined the pilot's decision-making process and the aircraft's warning systems. It was established that the pilot had intentionally bypassed a checklist item with the plan to return to it later. The investigation also looked into the effectiveness of the aircraft's undercarriage unsafe warning system, noting that the horn only activated when power was reduced at the threshold, providing insufficient time for corrective action.
Findings
- The pilot's decision to skip a checklist item created a situation where human error could occur.
- The pilot forgot to lower the undercarriage because his attention was diverted by the parachuting activity or due to environmental capture, where he expected the gear to be down.
- The aircraft's undercarriage unsafe warning system did not provide enough advance notice to allow for a timely gear extension or go-around.
- The aircraft's checklist did not formally document the requirement for a short final check of the undercarriage position, despite it being a standard practice for the operator.
Safety action
Following the incident, the operator provided the pilot with recurrent training focusing on checklist usage and the recognition of various warning horns. The Commission also recommended that the operator formally document the short final check on all aircraft checklists and emphasize the importance of following standardized procedures.