Narrative:

Inbound crew noted captain's window leaking. My flight was canceled and maintenance replaced the window overnight. The next morning; we were to ferry the aircraft. On departure passing through 10;000 ft; we heard a loud bang and air rushing through the captain's front window. This occurred at about 4.2 psi differential and the cabin altitude started climbing. We leveled off at 10;000 ft; decided oxygen masks were not required and asked for vectors back. We declared an emergency; ran all checklists and flew an ILS to landing and parked at the gate uneventfully.

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Original NASA ASRS Text

Title: A320 First Officer reports a loud bang and air escaping from the Captain's forward windshield during climb. The windshield had been recently replaced by maintenance and the crew elected to return to departure airport.

Narrative: Inbound crew noted Captain's window leaking. My flight was canceled and Maintenance replaced the window overnight. The next morning; we were to ferry the aircraft. On departure passing through 10;000 FT; we heard a loud bang and air rushing through the Captain's front window. This occurred at about 4.2 psi differential and the cabin altitude started climbing. We leveled off at 10;000 FT; decided oxygen masks were not required and asked for vectors back. We declared an emergency; ran all checklists and flew an ILS to landing and parked at the gate uneventfully.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.