Narrative:

Shortly after takeoff of scheduled flight between hou and dfw, a loud noise started coming from the capts side (sliding window). The noise increased as airspeed was increased out of 3000 ft, to the point where the cockpit communication was difficult. The problem was obvious, a pressure leak in the captain's sliding window. Also, although pressurization indications were normal before takeoff, there was a question in my judgement as to whether the aircraft would continue to pressurize as altitude was increased. I made the decision to return to the airport, and selected iah due to its longer runways, as the anti skid and consequently the autobrakes were on a maintenance carryover on this particular aircraft. Also, better maintenance capability with company at iah. No emergency was declared or special handling, as the aircraft remained at or below 4000 ft. Uneventful landing at iah and the problem entered in the aircraft logbook. Subsequently, mechanics discovered the aircraft window guide pin missing. Flight cancelled for maintenance.

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Original NASA ASRS Text

Title: MLG HAS LOUD NOISE FROM CAPT SLIDING WINDOW. CONCERNED REF PRESSURIZATION, MAKE PRECAUTIONARY LNDG.

Narrative: SHORTLY AFTER TKOF OF SCHEDULED FLT BTWN HOU AND DFW, A LOUD NOISE STARTED COMING FROM THE CAPTS SIDE (SLIDING WINDOW). THE NOISE INCREASED AS AIRSPD WAS INCREASED OUT OF 3000 FT, TO THE POINT WHERE THE COCKPIT COM WAS DIFFICULT. THE PROBLEM WAS OBVIOUS, A PRESSURE LEAK IN THE CAPT'S SLIDING WINDOW. ALSO, ALTHOUGH PRESSURIZATION INDICATIONS WERE NORMAL BEFORE TKOF, THERE WAS A QUESTION IN MY JUDGEMENT AS TO WHETHER THE ACFT WOULD CONTINUE TO PRESSURIZE AS ALT WAS INCREASED. I MADE THE DECISION TO RETURN TO THE ARPT, AND SELECTED IAH DUE TO ITS LONGER RWYS, AS THE ANTI SKID AND CONSEQUENTLY THE AUTOBRAKES WERE ON A MAINT CARRYOVER ON THIS PARTICULAR ACFT. ALSO, BETTER MAINT CAPABILITY WITH COMPANY AT IAH. NO EMER WAS DECLARED OR SPECIAL HANDLING, AS THE ACFT REMAINED AT OR BELOW 4000 FT. UNEVENTFUL LNDG AT IAH AND THE PROBLEM ENTERED IN THE ACFT LOGBOOK. SUBSEQUENTLY, MECHS DISCOVERED THE ACFT WINDOW GUIDE PIN MISSING. FLT CANCELLED FOR MAINT.

Data retrieved from NASA's ASRS site as of July 2007 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.