AO-2002-007 Piper PA23-250D Aztec and Piper PA34-200T Seneca II, ZK-DIR and ZK-MSL, near miss, about 25nm southwest of Napier, 10 June 2002

On Monday 10 June 2002 at about 1835, Piper PA23-250D Aztec ZK-DIR and Piper PA34-200T Seneca II ZK-MSL were flying the same track from Napier to Paraparaumu and climbing to their respective cruise altitudes when the required vertical separation between them was lost. At one stage the 2 aircraft were possibly at the same altitude, with a lateral separation of less than one km. The pilots were aware of the presence but not the proximity of the other aircraft. The loss of separation was identified only after radar information became available. Positive separation was quickly re-established and the 2 aircraft continued to their destinations as planned.

The loss in separation and following near miss was caused by a combination of the pilots not adhering to the requirements of their air traffic control clearances, local weather influences and a lack of progress information enabling the controller to adequately monitor the separation of the 2 aircraft during their climbs.

The safety issues identified were the need for pilots to ensure they fully complied with their air traffic control clearances and the requirement for air traffic control to increase the monitoring of the vertical separation of aircraft when using a rate of climb-based clearance. A safety recommendation was made to Airways Corporation concerning the latter issue.