Air Data Computers Require Inspection

United said Tuesday it was temporarily grounding 96 of its Boeing 757 airplanes so that it can perform checks on air data computers which had recently been modified.

In ordering the inspections, United admitted that it had not complied with some mandatory inspections. The move could strand thousands of passengers, as the 757 is a workhorse of United's fleet.

An airline spokesperson told the Wall Street Journal that the airline began cancelling flights Tuesday when it was revealed it was not in compliance with all aspects of an AD. Airplanes which were already on the ground were being inspected first, and each will be inspected at the next opportunity after it lands. The airline said no airplanes were being diverted, and that the planes are "fully functional."

United Continental Holdings acknowledged that it had not properly completed all the steps mandated by the FAA in checking the computers. The air data computers measure airspeed, pressure, and other parameters and make the data available to the airplane's auto pilot and other critical devices in the cockpit. The inspections, and flight cancellations, are expcted to continue through Wednesday.

FMI: www.unitedcontinentalholdings.com