Narrative:

During descent in visibility conditions, at 1200' over olm VOR, GPWS sounded warning, 'terrain, terrain.' oral warning was so loud that it was impossible to hear controller and difficult to communicate in cockpit. Warning was continuous until GPWS. Flap/gear switches were recycled. Warning then stopped. I was glad this happened in visibility conditions. Our flight handbook requires aggressive 15 degree pit up when this occurs IFR. At that location and altitude, this would have had a high midair possibility. Does not give me a high level of confidence in the GPWS system, which was to now have all the initial faults corrected. Our handbook procedure is intended for the low altitude regime, west/O proper thought for what we experienced. Callback conversation with reporter revealed the following: reporter states he was talking to flight manager recently and was told this same thing happened to a company aircraft in a holding pattern. He reacted as trained and pulled up 500'. A dangerous situation. Flight managed indicated that FAA has mandated a new parameter be used in the GPWS that is causing this problem. Reporter not sure, but thinks it regards closure rate. States that he feels like equipment discrepancy causes pilots to analyze rather than respond to warning, which is a true safety hazard. Apparently the false warnings occur when aircraft pass beneath. Reporter feels strongly that since FAA mandated this change, they should be made aware of the problem occurring.

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Original NASA ASRS Text

Title: ACR HAS FALSE GPW AS DESCENDING.

Narrative: DURING DSNT IN VIS CONDITIONS, AT 1200' OVER OLM VOR, GPWS SOUNDED WARNING, 'TERRAIN, TERRAIN.' ORAL WARNING WAS SO LOUD THAT IT WAS IMPOSSIBLE TO HEAR CTLR AND DIFFICULT TO COMMUNICATE IN COCKPIT. WARNING WAS CONTINUOUS UNTIL GPWS. FLAP/GEAR SWITCHES WERE RECYCLED. WARNING THEN STOPPED. I WAS GLAD THIS HAPPENED IN VIS CONDITIONS. OUR FLT HANDBOOK REQUIRES AGGRESSIVE 15 DEG PIT UP WHEN THIS OCCURS IFR. AT THAT LOCATION AND ALT, THIS WOULD HAVE HAD A HIGH MIDAIR POSSIBILITY. DOES NOT GIVE ME A HIGH LEVEL OF CONFIDENCE IN THE GPWS SYS, WHICH WAS TO NOW HAVE ALL THE INITIAL FAULTS CORRECTED. OUR HANDBOOK PROC IS INTENDED FOR THE LOW ALT REGIME, W/O PROPER THOUGHT FOR WHAT WE EXPERIENCED. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR STATES HE WAS TALKING TO FLT MGR RECENTLY AND WAS TOLD THIS SAME THING HAPPENED TO A COMPANY ACFT IN A HOLDING PATTERN. HE REACTED AS TRAINED AND PULLED UP 500'. A DANGEROUS SITUATION. FLT MANAGED INDICATED THAT FAA HAS MANDATED A NEW PARAMETER BE USED IN THE GPWS THAT IS CAUSING THIS PROB. RPTR NOT SURE, BUT THINKS IT REGARDS CLOSURE RATE. STATES THAT HE FEELS LIKE EQUIPMENT DISCREPANCY CAUSES PLTS TO ANALYZE RATHER THAN RESPOND TO WARNING, WHICH IS A TRUE SAFETY HAZARD. APPARENTLY THE FALSE WARNINGS OCCUR WHEN ACFT PASS BENEATH. RPTR FEELS STRONGLY THAT SINCE FAA MANDATED THIS CHANGE, THEY SHOULD BE MADE AWARE OF THE PROB OCCURRING.

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.