At around lunchtime on February 16, 2007, Frontier Airlines Flight 659 from Denver International Airport (DEN) to San Francisco International Airport (SFO) suffered a windshield fracture during the climb out of Denver. The plane performed an uneventful turn, landing safely back at Denver Airport. The aircraft involved in the incident was a three-year-old Airbus A319-100 with the registration N927FR.

According to the captain in command of the flight, they had just taken off from Denver's Runway 34L and were making a turn when the right windshield in front of the first officer cracked. The captain immediately alerted air traffic control (ATC) that he was returning to Denver.

14 planes had cracked windshields within the space of three hours

During the remainder of the afternoon, a total of 14 aircraft suffered fractured windshields. The crew of one of the aircraft reported that as they were turning in preparation for landing, they heard a loud thump and saw the first officer's windshield crack in the shape of a spider's web. Another plane suffered the same fate after taxing through some dirt that was being blown by the wind.

On the day of the windshield cracking incidents, strong winds had been blowing through the Colorado foothills. The weather was also freezing cold, with parts of Colorado's Interstate 70 highway having to be shut down due to whiteouts caused by blowing snow. Some ski areas were also closed after it was deemed unsafe to operate ski lifts due to the severe winds.

When speaking about the cracked windshields with ABC News, pilot and aviation consultant John Nance said:

"This is not only unusual, I know of no precedent for anything like this where multiple windshields have been cracked, simply by being in a particular place at a particular time."

Aircraft windshields are very strong

Windshields on aircraft are designed to be extremely strong so that they can survive bird strikes and anything else that might come into contact with them. Occasionally, though, they do crack, and the pilots land at the nearest airport. Explaining what he thought may have caused the cracks, Nance added:

"The two most likely causes of cracked windshields are simply the internal heat system being misapplied or not heating uniformly or having a bird hit it at a really high rate of speed in the air."

Denver International Airport is at an elevation of 5,342 feet and is located 16 miles northeast of the city. Entirely surrounded by fields, construction work at the airport was taking place at the time of the incidents, and the wind was gusting up to 48mph. Before the event, several snowstorms had impacted Denver and the surrounding area. The airport lays down sand to keep the runways and taxiways clean and clear of ice, and it is believed that the sand and the wind contributed to the cracks.

Fine particles of sand were responsible

When examining the cracked windshields, the National Transportation Safety Board (NTSB) said that it found fine particles of sand. They concluded that the sand caused pitting, which led to the outer layer of the windshields cracking. At no time were the planes and passengers in danger, but the airborne pilots did the right thing by getting the aircraft on the ground as soon as possible.

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  • Denver international conspiracy theories
    Denver International Airport
    IATA/ICAO Code:
    DEN/KDEN
    Country:
    United States
    CEO:
    Phillip A. Washington
    Passenger Count :
    58,828,552 (2021)
    Runways :
    7/25 - 3,658m (12,000 ft) | 8/26 - 3,658m (12,000 ft) | 16L/34R - 3,658m (12,000 ft) | 16R/34L - 4,877m (16,000 ft) | 17L/35R - 3,658m (12,000 ft) | 17R/35L - 3,658m (12,000 ft)