Narrative:

During our first flight of the day; the captain and I noticed that the standby altimeter was off by about 400 ft; and the standby airspeed indicator was off by about 20 KTS at the worst. During the captain's postflt; he noticed that the standby pitot tube was bent slightly outward. The crew that flew the aircraft previous to us wrote up the standby altimeter; as well as the rudder limiter. Because of these previous write-ups; I believe that the damage occurred before the aircraft got to ZZZ. On my preflight in ZZZ I made sure that the pitot covers were off; and that the intakes were clear of debris. I believe that the skirt of the jetbridge; while not actually touching the pitot tubes; was in a position that would have made it difficult to detect such a discrepancy.

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Original NASA ASRS Text

Title: SF340 FLT CREW REPORTS STANDBY ALTIMETER AND AIRSPEED SEVERELY OFF IN CRUISE. POST FLIGHT REVEALS BENT PITOT TUBE.

Narrative: DURING OUR FIRST FLT OF THE DAY; THE CAPT AND I NOTICED THAT THE STANDBY ALTIMETER WAS OFF BY ABOUT 400 FT; AND THE STANDBY AIRSPD INDICATOR WAS OFF BY ABOUT 20 KTS AT THE WORST. DURING THE CAPT'S POSTFLT; HE NOTICED THAT THE STANDBY PITOT TUBE WAS BENT SLIGHTLY OUTWARD. THE CREW THAT FLEW THE ACFT PREVIOUS TO US WROTE UP THE STANDBY ALTIMETER; AS WELL AS THE RUDDER LIMITER. BECAUSE OF THESE PREVIOUS WRITE-UPS; I BELIEVE THAT THE DAMAGE OCCURRED BEFORE THE ACFT GOT TO ZZZ. ON MY PREFLT IN ZZZ I MADE SURE THAT THE PITOT COVERS WERE OFF; AND THAT THE INTAKES WERE CLR OF DEBRIS. I BELIEVE THAT THE SKIRT OF THE JETBRIDGE; WHILE NOT ACTUALLY TOUCHING THE PITOT TUBES; WAS IN A POS THAT WOULD HAVE MADE IT DIFFICULT TO DETECT SUCH A DISCREPANCY.

Data retrieved from NASA's ASRS site as of May 2009 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.