Narrative:

Shortly after descent from altitude, heard and felt mild thump and aircraft movement. No visible problem from cockpit. Upon landing, maintenance found aircraft left landing light cover broken and missing. Fwd water drain valve found open in fwd lav (water drain in drain position). Ice must have broken off and hit glass cover. This was not seen on walk around due to no pressure on water system. Water drain not a normal preflight check from inside. Will be from now on in winter as maintenance drains lines for cold WX operations.

Google
 

Original NASA ASRS Text

Title: MLG CREW HAD ACCUMULATED ICE DAMAGE THE ACFT LNDG LIGHT COVER.

Narrative: SHORTLY AFTER DSCNT FROM ALT, HEARD AND FELT MILD THUMP AND ACFT MOVEMENT. NO VISIBLE PROB FROM COCKPIT. UPON LANDING, MAINT FOUND ACFT LEFT LNDG LIGHT COVER BROKEN AND MISSING. FWD WATER DRAIN VALVE FOUND OPEN IN FWD LAV (WATER DRAIN IN DRAIN POS). ICE MUST HAVE BROKEN OFF AND HIT GLASS COVER. THIS WAS NOT SEEN ON WALK AROUND DUE TO NO PRESSURE ON WATER SYS. WATER DRAIN NOT A NORMAL PREFLT CHECK FROM INSIDE. WILL BE FROM NOW ON IN WINTER AS MAINT DRAINS LINES FOR COLD WX OPS.

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.