Fuel balancing led to crash

The Metroliner broke up in the air before crashing on farms near Stratford. File Picture

The crew of an Airworks Metroliner that burst into flames and crashed over Stratford last year had been flying the plane on a steep angle in an attempt to rebalance the fuel in mid-flight.

A Transport Accident Investigation Commission report into the crash, which killed pilot Clive Rodger Adamson, 43, of Wellington, and first officer Tony Brian Arthur Drummond, 41, of Bucklands Beach, Manukau City, was released yesterday.

The Metroliner was carrying NZ Post courier cargo from Auckland to Blenheim when it crashed about 10.15pm on May 3, 2005, 5km east of Stratford.

Several witnesses reported a loud and unusual noise, described by some as sounding like an aircraft engine high-revving or roaring.

Witnesses saw up to four separate fireballs descending through cloud layers at speed.

The report said the accident was unsurvivable.

The cockpit voice recorder revealed that in the moments before the crash the crew had been balancing fuel while the aircraft was on autopilot.

The pilot had instructed the first officer to fly the plane at a large sideslip angle, using the rudder trim control.

In response to instructions from the pilot, the first officer sought confirmation of the procedure saying he was being a "bit cautious".

The pilot responded "don't be cautious mate, it'll do it good".

The report noted the first officer's comment "probably represented some concern felt by the first officer that the rudder input called for was excessive, but he apparently complied with the instruction anyway".

Shortly after this exchange the aircraft began to turn quickly to the left, and to descend.

The crew attempted to recover the aircraft from its "unusual attitude" but it went into a spiral dive, and broke up before crashing.

The report said although the crew were appropriately licensed and qualified for the aircraft and flight, the first officer was not experienced on the Metroliner. "In this senior-junior situation there was an inevitable cross-cockpit authority gradient, with the captain taking on an instructing role and the first officer requiring confidence if he was to assertively query an instruction that he thought was wrong," the report said.

Meanwhile the pilot clearly did not understand that the technique he used to balance the fuel was unsafe while flying on autopilot.

The report said if the aircraft had been manually flown during the fuel-balancing manoeuvre the loss of control would probably not have occurred.

The report recommended the flight manuals of the Metroliner and associated types to caution that the autopilot and yaw damper must be disconnected while in-flight fuel balancing was done.

- NZPA