Last
September, we announced three enhancements to the 737 rudder system
as the result of work carried out for several years by Boeing, the
U.S. Federal Aviation Administration, and the U.S. National Transportation
Safety Board. These enhancements should be taken in context: After
more than 100 million flight-hours, the 737 family has proved itself
among the safest and most reliable of all airplanes. Its safety
record is twice as good as the average of the worldwide commercial
jet fleet.
However, even this fine
airplane can be enhanced, so we are simplifying flight crew procedures,
increasing maintenance oversight, and modifying the rudder control
system. The simplified flight crew procedures will have been implemented
by the time you read this issue of Aero, and the enhanced maintenance
regimen for Classic 737s will be implemented early in 2001. We expect
the enhanced rudder power control unit (PCU) to be incorporated
into production airplanes in mid-2003; our current plan is to have
retrofit kits available in the third or fourth quarter of that year.
While the existing PCU
is redundant and has proved itself reliable, we have developed a
new concept that eliminates the dual concentric valve that has been
the subject of concerns in the past. It makes a major change to
the system; however, the enhanced PCU is based on proven technology,
will fit within the existing airplane structure, and will be relatively
simple to retrofit. With this enhancement, the 737 rudder system
essentially will be functionally equivalent to the 757 system.
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