Narrative:

I was performing PF duties on this trip from charlotte, nc, to tri cities, nc. Our clearance was to fly the hornet 3 departure to robay intersection, then direct holston, mt (hmv), direct tri cities airport. En route climb to 14000 ft on the autoplt was normal. Center controled us until about 30 mi from hmv and gave us direct hmv. We were then switched over to tri cities approach. Approach gave us a descent clearance to 5400 ft which we did. At about 7000 ft we entered the clouds and continued the descent to 5400 ft. At approximately 5800 ft as the autoplt was shallowing the descent rate to level, the aural 'terrain, terrain...' and flashing red GPWS alert lights came on. My first officer confirmed what I saw and noted our radio altitude at approximately 1800 ft. He asked approach control for an altitude check while I disconnected the autoplt, went to firewall power and initiated a pull-up. The warnings continued for several seconds as we continued to climb. It was at approximately 6800 ft that the terrain warnings stopped. I leveled the aircraft at approximately 7500 ft in the clear and then started a slow descent back to 7000 ft where we told approach control we would level until we figured everything out. Approach control told us that he had noted other medium large transport aircraft having the same problem over hmv (in fact, the crew that brought in our airplane the next day had a similar warning, however they were in the clear and visual on all terrain). An uneventful approach and landing followed. This, of course, is a very disconcerting event to the crew, flight attendants and passengers who all heard the terrain warning. The fact that it took about 1000 ft for the warning to stop did not seem right. On the ground, we called our maintenance department and they seemed to think the radar altimeter may have experienced some anomaly and it took some time to reset itself. I wonder if approach control has to descend traffic to 5400 ft over hmv as the VOR is on a mountain top. This gives only the min safe altitude over the VOR and obviously some descent rates in this vicinity are causing at least one commercial airliner type to enter the terrain envelope of the GPWS. Perhaps a slightly higher altitude restriction at hmv would be helpful until passing the terrain. In addition, our company's maintenance personnel should also be working on the radar altimeter and GPWS to correct this type of situation.

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Original NASA ASRS Text

Title: GPWS ACTIVATED ON DSCNT INTO TRI, TN, AS CLRED.

Narrative: I WAS PERFORMING PF DUTIES ON THIS TRIP FROM CHARLOTTE, NC, TO TRI CITIES, NC. OUR CLRNC WAS TO FLY THE HORNET 3 DEP TO ROBAY INTXN, THEN DIRECT HOLSTON, MT (HMV), DIRECT TRI CITIES ARPT. ENRTE CLB TO 14000 FT ON THE AUTOPLT WAS NORMAL. CTR CTLED US UNTIL ABOUT 30 MI FROM HMV AND GAVE US DIRECT HMV. WE WERE THEN SWITCHED OVER TO TRI CITIES APCH. APCH GAVE US A DSCNT CLRNC TO 5400 FT WHICH WE DID. AT ABOUT 7000 FT WE ENTERED THE CLOUDS AND CONTINUED THE DSCNT TO 5400 FT. AT APPROX 5800 FT AS THE AUTOPLT WAS SHALLOWING THE DSCNT RATE TO LEVEL, THE AURAL 'TERRAIN, TERRAIN...' AND FLASHING RED GPWS ALERT LIGHTS CAME ON. MY FO CONFIRMED WHAT I SAW AND NOTED OUR RADIO ALT AT APPROX 1800 FT. HE ASKED APCH CTL FOR AN ALT CHK WHILE I DISCONNECTED THE AUTOPLT, WENT TO FIREWALL PWR AND INITIATED A PULL-UP. THE WARNINGS CONTINUED FOR SEVERAL SECONDS AS WE CONTINUED TO CLB. IT WAS AT APPROX 6800 FT THAT THE TERRAIN WARNINGS STOPPED. I LEVELED THE ACFT AT APPROX 7500 FT IN THE CLR AND THEN STARTED A SLOW DSCNT BACK TO 7000 FT WHERE WE TOLD APCH CTL WE WOULD LEVEL UNTIL WE FIGURED EVERYTHING OUT. APCH CTL TOLD US THAT HE HAD NOTED OTHER MLG ACFT HAVING THE SAME PROBLEM OVER HMV (IN FACT, THE CREW THAT BROUGHT IN OUR AIRPLANE THE NEXT DAY HAD A SIMILAR WARNING, HOWEVER THEY WERE IN THE CLR AND VISUAL ON ALL TERRAIN). AN UNEVENTFUL APCH AND LNDG FOLLOWED. THIS, OF COURSE, IS A VERY DISCONCERTING EVENT TO THE CREW, FLT ATTENDANTS AND PAXS WHO ALL HEARD THE TERRAIN WARNING. THE FACT THAT IT TOOK ABOUT 1000 FT FOR THE WARNING TO STOP DID NOT SEEM RIGHT. ON THE GND, WE CALLED OUR MAINT DEPT AND THEY SEEMED TO THINK THE RADAR ALTIMETER MAY HAVE EXPERIENCED SOME ANOMALY AND IT TOOK SOME TIME TO RESET ITSELF. I WONDER IF APCH CTL HAS TO DSND TFC TO 5400 FT OVER HMV AS THE VOR IS ON A MOUNTAIN TOP. THIS GIVES ONLY THE MIN SAFE ALT OVER THE VOR AND OBVIOUSLY SOME DSCNT RATES IN THIS VICINITY ARE CAUSING AT LEAST ONE COMMERCIAL AIRLINER TYPE TO ENTER THE TERRAIN ENVELOPE OF THE GPWS. PERHAPS A SLIGHTLY HIGHER ALT RESTRICTION AT HMV WOULD BE HELPFUL UNTIL PASSING THE TERRAIN. IN ADDITION, OUR COMPANY'S MAINT PERSONNEL SHOULD ALSO BE WORKING ON THE RADAR ALTIMETER AND GPWS TO CORRECT THIS TYPE OF SITUATION.

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.