Jet grounded after mid-air shakes

CHRISTIAN WOLMAR

Transport Correspondent

A British Airways Boeing 737 which started shaking uncontrollably on a test flight has been grounded indefinitely by accident investigators who hope it may solve the mystery of two US plane crashes in which a total of 157 people died.

The 737 is being subjected to a major examination by the Air Accident Investigation Branch following the incident on a test flight of the aircraft after an overhaul. The pilot of the BA 737-200 was at about 20,000 feet and travelling at 540mph when he suddenly reported "rapid-roll oscillations". He was able to land safely.

Boeing 737s are the world's most widely used commercial jet aircraft, with more than 2,500 in service. If a major design fault were discovered which needed immediate remedial treatment, it would lead to serious disruption of services. BA has 67 of the planes and said yesterday there had been no problems with its other aircraft.

In March 1991, 25 people were killed when a Boeing 737-200 crashed on its approach to Colorado Springs. In September 1994 all 132 on board were killed when a 737 plunged to the ground near Pittsburgh after flipping right over about 10 miles short of its destination.

Neither accident has been explained but investigators suspected a problem with the rudder, causing pilots to lose control.

Boeing, which has had a team working on the problem since the first crash, has made more than 20 modifications to rudder equipment of the 737.

The Air Accident Investigation Branch has been asked by its US counterpart for details of any similar incidents both in Britain and in Europe.

In the US, there have been at least 47 unexplained losses of control on 737s since the Pittsburgh crash, according to Federal Aviation Administration records.

As other countries may not have reported incidents, the Americans are trying to find out about other cases in an effort to find the cause. One safety expert said: "The number of incidents is worrying but the difficulty is that we have been unable to pinpoint the source of the problem. British Airways last night confirmed that its plane, which had been used for flights out of Gatwick, had been impounded until further notice. A spokesman said: "We have no idea for how long they will need the aircraft."