A jet airliner plunging towards the ground at 21,000 feet a minute was a mere 15 seconds from crashing in Norfolk, according to a report from the Air Accidents Investigation Branch.

A jet airliner plunging towards the ground at 21,000 feet a minute was a mere 15 seconds from crashing in Norfolk, it emerged last night.

As the Boeing 737 easyJet aircraft nosedived during a test flight over the region earlier this year there was also 'confusion between the two pilots', according to a preliminary report from the Air Accidents Investigation Branch (AAIB).

The incident happened just west of Norwich on January 12 at 3.45pm, and was described as 'a serious incident' with the aircraft's nose 30 degrees down at one stage.

The AAIB said confusion also arose on the flight deck with the 43-year-old easyJet captain incorrectly thinking that hydraulic power, which was switched off for the test, had been restored to the flight controls.

The captain rolled the aircraft left at more than 90 degrees to try to stabilise it and with the plane travelling at 500mph, he pushed the controls backwards and made an emergency call to air traffic controllers.

The plane, with an easyJet first officer co-pilot and two passengers on board, eventually recovered from the dive at about 5,600ft in a layer of cloud.

The flight was abandoned and the pilots took the plane safely back to Southend. The plane, made in 2002, was at the end of its lease and was being checked following maintenance while it was demonstrated to a representative of another airline, with a representative of the plane's owner also on board.

The captain of had flown the plane the previous month to Southend for maintenance and had carried out tests during that journey. He had found that the amount of 'manual stabiliser trim wheel adjustment' required to balance the aircraft in level flight was within, but very close to, the approved maintenance manual limits.

He had verbally requested that this be looked at but decided not to enter it in the tech log as the stabiliser trim levels were just within limits.

The report said: 'The absence of a formal post-flight debrief and formal written record resulted in the balance tabs, attached to the elevators of the aircraft, being adjusted in the opposite sense to that identified as necessary. The aircraft was therefore significantly out of trim during the post-maintenance test flight and it was that which initiated the pitch-down incident during the manual reversion test.'

EasyJet suspended further check flights until it had carried out a review of maintenance procedures, check pilot procedures and flight check schedules.

The Civil Aviation Authority is also reviewing its guidance on flight control checks, to make sure they are not open to misinterpretation. It is also planning to publish guidance covering the co-ordination between maintenance companies and airline operators on how check flights are carried out.

The AAIB investigation is continuing and a final report will be published later.