United Airlines says passengers on some international and long-distance routes should expect delays or cancellations while it tests dozens of Boeing 777s.

The airline is making sure a cargo fire suppression system is working properly. A review of records showed a test on part of the system had not been performed.

United says testing will be done on 52 of the planes over 36 hours. So far, a dozen of the planes have passed inspection and have been cleared to fly.

The Federal Aviation Administration has been cracking down on airlines for missing safety inspections.