Unrepaired Windscreen Caused Fire on United Aircraft

The National Transportation Safety Board (NTSB) has determined a fire that occurred on a United Airlines Boeing 757 during a flight from New York to Los Angeles was caused by a faulty windscreen heater that had not been repaired properly.

Back in May 2010, the United flight reached cruising altitude and the pilot started to hear a "sizzle" before 14-16 inch flames started to appear from below the windshield. He quickly responded by putting out the flames with a Halon fire extinguisher. The flames quickly reignited and he had to use a second extinguisher to completely put the fire out, according to the NTSB.

The fire resulted in the left windscreen cracking. With the co-pilot at the controls, the aircraft, with 105 passengers and seven crew onboard made an emergency landing at Washington Dulles International Airport in Virginia. No one was injured in the incident.

Earlier the same day, another pilot flying the same aircraft had reported fumes and an electrical connection that had overheated. The day prior, the aircraft had to make an unscheduled landing in Las Vegas due to smoke and fumes in the cockpit, according to NTSB investigators.

The plane was still authorized to fly, since United's maintenance manual states an airplane can be flown an additional 50 hours after a burned window heater electrical connector has been discovered.

"We did a full inspection and believed the plane was flight worthy," United spokeswoman Megan McCarthy told the AP.

Investigators have found the cause of the windscreen heater issue was a loose screw. Since the incident, the Federal Aviation Administration (FAA) has required airlines to inspect the cockpit window heaters on 1,212 Boeing aircraft.

United told the AP that they have complied with the FAA and have made "enhancements to our maintenance program."