Air Transport

Aviation safety investigators are working to clear up a mystery spate of cracked windshields around the Denver area in the course of three hours on one day last week.

US National Transportation Safety Board (NTSB) investigators hope to establish by the end of the week a cause for a rash of airline windshield failures on or near Denver international airport on 16 February during what is considered normal weather conditions for the time of year.

According to the NTSB official in charge of the investigation, Jennifer Kaiser, 22 windscreens failed on 14 aircraft between 12:20 and 15:30 that day - including nine from regional carrier SkyWest Airlines’ fleet.

Affected aircraft included Airbus A318s and A319s, Bombardier CRJ200s and CRJ700s, an Embraer EMB-120 and a Raytheon Beech 1900.

At least two aircraft had aborted their takeoffs after windscreens cracked; other failures occurred at the gate or in flight.

A SkyWest spokeswoman says eight of the airline’s aircraft were flying the next day. However, a reason for such destruction has yet to be ascertained. Pilots reported nothing unusual in terms of weather that afternoon, according to Kaiser.

The NTSB is assembling meteorological information from that afternoon, which Kaiser says included a mixture of “windy, cold, warm and snowing” conditions. An official with the National Centre for Atmospheric Research, located just north of Denver, says the consensus among resident experts was that “nothing that unusual was going on in terms of weather”.

The US National Weather Service’s office for Denver and Boulder, Colorado reported a maximum temperature for the day of 7ºC (45ºF) at 12:27, dropping to the day’s minimum temperature of -1ºC at 16:44.

Experts from windshield manufacturers PPG Aerospace and Saint-Gobain were en route to Denver to examine the 22 windscreens.