Seasprite Court Of Inquiry: Summary Of Findings

The Court of Inquiry for the accident involving a Royal New Zealand Navy Seasprite Helicopter on board HMNZS Te Mana during First of Class Flight Trials (FOCFT) has been completed. The trials involve determining the safe operating limits of ship’s pitch and roll, wind strengths and aircraft handling under normal and emergency conditions. On 20 February 2002, during FOCFT, Seasprite NZ3604 made a heavy landing onto the frigate HMNZS Te Mana resulting in significant damage to the aircraft. The Court of Inquiry found that the heavy landing was the result of a unique and largely unforeseeable combination of ship motion and aircraft rate of descent at the moment of touchdown.

Air Vice-Marshal John Hamilton, Chief of Air Force said, “These events, when taken in the context of the inherently greater risk involved in FOCFT, all contributed to a greater or lesser degree to the accident. No one significant event has emerged as being pivotal to, or directly causative of, the accident. Accordingly, few recommendations could be made by the court to specifically improve procedures or practices in avoiding such incidents.”

Seasprite Court Of Inquiry: Summary Of Findings

Questions and Answers

What are First of Class Flight Trials (FOCFT)?

The First of Class Flight Trial process seeks to determine the safe operating limits for the aircraft from a ship under normal and emergency conditions. The limits are computer modelled prior to the commencement of the trial; the flying trial itself sees a gradual expansion of the limits, from the benign to the extremes of the modelled envelope. In this case, the FOCFT task plan called for two sorties to be conducted in “degraded” mode – in this case being flown with either the Automatic Stabilisation Equipment (ASE) off, or the hydraulic boost off.

What happened during the accident?

The incident trials took place in Cook Straight. The wind was south-south westerly at approximately 20 knots with a sea state of 3 – 4. The ship was pitching 2 – 3 degrees (occasionally 4 degrees) and rolling up to 7 degrees.

The second sortie of the day was planned to investigate known data point in three stages: Automatic Stabilisation Equipment (ASE) off, ASE off and lateral coupler disengaged, and hydraulics off. The first two approaches/landings/launches were conducted uneventfully. The third landing required the hydraulic boost to be disabled, a scenario that significantly increases the pilot’s workload. With the Test Pilot at the controls, the Seasprite hovered over the deck, and after a period of time, descended. The aircraft impacted the deck heavily resulting in significant damage to the landing gear.

What is the cost of the repair?

The cost of damage to the aircraft has been estimated at approximately $7.4 million (NZD).

Why has the Court of Inquiry taken so long?

The incident occurred on 20 February 2002. The Air Component Commander, HQ Joint Force NZ assembled a Court of Inquiry at RNZAF Base Auckland on 21 February 2002.

The Court of Inquiry recorded evidence from a total of 40 witnesses, and considered a total of 114 exhibits. Several witnesses were re-interviewed to obtain additional evidence during the course of the inquiry. In the process of recording evidence the Court was required to travel to Auckland, Ohakea, Sydney and Nowra, and coordinate witness interviews around the passage programme for HMNZS Te Mana. Much of the evidence recorded by the Court was technical in nature and involved assessment and comment on flight data and procedures.

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