When the rudder swung all the way to the side, the pilots could not regain control of the plane.

The design of the replacement mechanism has not been completed, and the cost of the repairs is unknown. The existing rudder control was considered redundant but is apparently not. While two hydraulic cylinders control the rudder, a problem with one cylinder may inactivate the backup cylinder.

The recall involves 1,500 737s in the United States, and about 2,000 foreign 737s probably also will be repaired. The repairs will be done as part of routine maintenance on the 737, which remains, on average, quite a safe airplane.

Bibliography:
F.A.A. Will Require Changes for Rudders on Boeing 737s, Matthew Wald, The New York Times, Sept. 14, 2000, p. A14.