Air NZ engine may have backfired

An investigation into the emergency landing of an Air New Zealand Boeing 767 found problem was caused by an engine reaction similar to a car backfiring. Photo / Richard Robinson

A bird strike has been ruled out as causing the engine problem which forced the emergency landing of an Air New Zealand plane. Early indications suggested the engine "backfired".

Investigations are continuing into what caused the problem which led to a Boeing 767-300 making an emergency landing at Auckland Airport on Thursday afternoon.

Some of the 206 passengers on Perth-bound flight NZ175 reported seeing flames and smoke coming from the left engine and loud banging and shuddering about 600m after take-off.

Air New Zealand initially said a bird strike was one possibility but that has been ruled out after no damage was found to the engine.

The airline's general manager of operations and safety, Captain Dave Morgan, said that indicated the problem lay with the main engine control.

He said an interruption to the airflow through the left-hand engine caused a flare and was "a similar reaction to a car backfiring".

The main engine control, "akin to a carburettor", had been sent to its US manufacturer for tests.

"It will probably be about two to three weeks before we get some indication."

A new main engine control had been fitted to the aircraft, which has been put through power tests.

Today the plane will have a test flight and could be back in service this afternoon.

Aviation expert Peter Clark said this kind of engine problem was "very uncommon".

He said although no cause had been determined, passengers flying on Boeing 767's should not be worried.

"This is a well proven engine on a well proven aircraft. I wouldn't get stressed thinking there is an inherent problem on the aircraft."

Mr Clark said it was important to understand all twin-engine aircraft were designed to take off safely on one engine.