United Grounds 52 Boeing 777s For Inspections

United Airlines today warned customers of delays and cancellations as it inspects the 52 planes in its Boeing 777 fleet.

United is the latest in a string of carriers, including American Airlines, Delta Air Lines and Southwest Airlines, that have cancelled flights for aircraft inspections, amid a Federal Aviation Administration audit of domestic airline maintenance records.

"As part of a regular review of maintenance records, the company discovered that the functional test that checks the firing system on one of the five bottles in the cargo fire suppression system on the Boeing 777 was not performed, and this was voluntarily disclosed to the FAA," United said in a statement today.

United said it would not operate the planes until it completes the inspections, but would work "to provide additional aircraft where available" and rebook customers on other United flights or on flights operated by competitors.