Air New Zealand is stressing that, despite releasing initial findings, French investigators have yet to determine the cause of last November's Airbus A320 accident off Perpignan.

In particular, the carrier cites evidence of a failure of two stall-warning devices on the aircraft apparent in flight-data recorder traces which accompany a preliminary 53-page report from the Bureau d'Enquetes et d'Analyses.

The BEA does not highlight the recordings in its report, which details the dynamics of the aircraft's behaviour as the crew attempted to perform a low-speed flight test even though the aircraft was at low altitude and preparing to conduct an approach to Perpignan Airport.

Air New Zealand says the report "only partially outlines certain aspects" of occurrences during the flight and does not identify the cause of the crash, which killed all seven people on board the jet.

Chief executive Rob Fyfe points out that the BEA "provides a small insight" into the apparent failure of two stall-warning vanes.

On the flight-data recorder trace, the BEA simply states that the local angle-of-attack values became "frozen" as the aircraft cruised at 32,000ft, some 20min after take-off.

The aircraft had undergone painting in Perpignan and, in January, Airbus warned operators to take care to protect aerodynamic sensors during painting and maintenance work.

Fyfe also cautions that the report gives "selected information" about cockpit activity, and adds: "We expect the full report, which may not be completed for some time, to have detailed analysis of all factors that contributed to this tragic accident, so that any lessons learned can be shared across the industry."

The jet was being operated by an XL Airways crew on a test flight ahead of being delivered off-lease back to Air New Zealand on 27 November.

In addition to the two XL pilots, a pilot and three engineers from Air New Zealand were on board, plus a New Zealand civil aviation authority representative.

"None of what occurred during this pre-delivery acceptance flight gives us any concern for the normal commercial operation of the A320 fleet, which is an integral part of our operations," says Fyfe.

Source: Air Transport Intelligence news