Colorado Aviation Accidents & Incidents

HISTORY OF FLIGHT

On April 9, 2004, at approximately 1000 mountain daylight time, a Beech 1900D, N210GL, operated by Great Lakes Aviation, Incorporated, sustained a cracked copilot's windshield when the airplane's windshield anti-ice system was activated. Subsequent arcing and smoke was observed originating from a terminal block for the anti-ice system. The crew took remedial action and subsequently made an uneventful landing at the Denver International Airport (DEN), Denver, Colorado. The incident occurred during cruise flight approximately 45 miles north of the Pueblo Municipal Airport (PUB), Pueblo, Colorado. Instrument meteorological conditions (IMC) prevailed at the time of the incident. The positioning flight from PUB, to DEN, was being conducted on an instrument flight rules flight plan under the provisions of Title 14 CFR Part 91. The captain and first officer on board reported no injuries. The flight originated at approximately 0930.

The captain reported that he had placed the windshield heat to the "normal" position and then called for the climb checklist. The captain said they were operating in and out of IMC conditions. As they were leveling off at 11,000 feet mean sea level (msl), approximately 45 nautical miles north of the Pueblo VOR the captain said, " ... we experienced a popping sound as the result of the first officer's windshield beginning to crack. There were 4 or 5 cracks that started from the bottom left hand corner of the windshield and reached the halfway point of the windshield. At that time and almost instantly we heard another pop and those same cracks continued up the entire length of the windshield." The captain said that after the window had cracked completely, he heard the first officer say, "it's burning." The captain said he asked him what was burning and he replied, "the windshield." The captain said he turned off the heat on his side of the windshield and removed his approach plates from the glare shield. He said he looked over to see what was going on, but did not see any smoke or fire. The captain said he called for the "cracked or shattered windshield checklist." They completed the checklist and continued to Denver where they landed the airplane uneventfully.

The first officer said they were in level cruise at 11,000 feet msl, and 9 miles east of Colorado Springs, Colorado, when he noticed constant sparking at the bottom left corner of his windshield. He said he brought it to the captain's attention. The first officer said they turned off the windshield anti-ice switch for his side and the sparking stopped. The first officer said, "A few seconds later, my side of the windshield cracked in different places."

Both crew members reported the outside air temperature as minus 12 degrees Celsius.

TESTS AND RESEARCH

An examination of the windshield showed six cracks in the outer pane originating at a location 6 inches inboard of the center post along the anti-ice terminal strip. Approxim