Narrative:

I was flying the B727 on base leg for vectors to ILS runway 36L in huntsville, al. We were told to descend to 2800 ft MSL. Passing through 3000 ft MSL, we received a GPWS alert warning of 'terrain, terrain.' I immediately initiated the prescribed procedure of firewall power and pitch to 20 degrees nose up. The warning continued for about 10-15 seconds. When it ceased, we leveled off at about 5200 ft MSL and notified ATC. They stated that 2800 ft MSL was minimum vectoring altitude and that another aircraft had reported a GPWS warning in the same general area earlier in the evening. In addition, ground control told us that they have had a history of these warnings in the same area. This was a very unsettling feeling due to the poor WX conditions (IMC, ice, night, etc) and the recent accident in south america. I felt the entire crew performed very well and in a timely manner. I received excellent support throughout the maneuver from both the captain and so. Callback conversation with reporter revealed the following information: reporter stated that ground controller confirmed that there had been a prior GPWS earlier that evening, a flight from the reporter's company. In fact, the controller said that there had been several other events with GPWS during previous operations. The time frame was not known. The aircraft had to have the engines inspected as the PF had 'firewalled' the engines in the climb maneuver, overtemping them in the process. The aircraft was ferried back to atl the next day. The engine manufacturer is still studying the tape readouts from the flight data recorder to determine status of engines. The engines were operated in excess power for a period of 8 seconds. 'Someone' from 'safety' called the captain to discuss the situation. The aircraft had its spoiler-speed brakes deployed. The crew, in cognizance of the latest accident in south america, did not fail to remember the aircraft's confign and retracted the spoilers on the map. Supplemental information from acn 325200: the first officer was flying the aircraft. We were 24 mi southeast of rocket VOR and descending to 2800 ft which was the initial approach altitude. We were in light rime icing. Wing and engine anti- ice were on. Passing through 3000 ft, we heard the GPWS warning, 'terrain, terrain.' the first officer firewalled the engines and increased pitch to 20 degrees (up). I noticed the TA/vsi was pegged in a climb and the radio altimeter was not showing any reading. The terrain warning continued. The so said, 'keep it climbing.' passing through 4000-4800 ft, the terrain warning stopped. We leveled off. Duration of the warning was approximately 30 seconds. (Note: flight recorder data showed we were at firewall power for 8 seconds. It seemed longer to us.) I called huntsville approach and informed them of what happened, and why we were at 4800 ft. I asked them what the minimum vectoring altitude was in our area. Approach replied, '2800 ft.' they also said that a B737 had reported a GPWS alert earlier in the evening in the same area. The so made a PA informing the passenger that we had an erroneous terrain alert. The flight attendants later said it felt like a normal go around. During the approach briefing, I noted the terrain obstacles were towers located mostly to the northeast of the airport, with one 1910 ft tower to the southeast. Although we were all confused by a GPWS alert at what we thought was a safe altitude, an immediate terrain avoidance maneuver was initiated by the first officer, and backed up by the so and I. After landing, huntsville ground said the area southeast of huntsville airport had a history of erroneous GPWS warnings.

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Original NASA ASRS Text

Title: MVA ALT IN QUESTION AS ACR B727 RECEIVES A GPWS IN DSCNT DURING RADAR VECTORING IN A NIGHT OP.

Narrative: I WAS FLYING THE B727 ON BASE LEG FOR VECTORS TO ILS RWY 36L IN HUNTSVILLE, AL. WE WERE TOLD TO DSND TO 2800 FT MSL. PASSING THROUGH 3000 FT MSL, WE RECEIVED A GPWS ALERT WARNING OF 'TERRAIN, TERRAIN.' I IMMEDIATELY INITIATED THE PRESCRIBED PROC OF FIREWALL PWR AND PITCH TO 20 DEGS NOSE UP. THE WARNING CONTINUED FOR ABOUT 10-15 SECONDS. WHEN IT CEASED, WE LEVELED OFF AT ABOUT 5200 FT MSL AND NOTIFIED ATC. THEY STATED THAT 2800 FT MSL WAS MINIMUM VECTORING ALT AND THAT ANOTHER ACFT HAD RPTED A GPWS WARNING IN THE SAME GENERAL AREA EARLIER IN THE EVENING. IN ADDITION, GND CTL TOLD US THAT THEY HAVE HAD A HISTORY OF THESE WARNINGS IN THE SAME AREA. THIS WAS A VERY UNSETTLING FEELING DUE TO THE POOR WX CONDITIONS (IMC, ICE, NIGHT, ETC) AND THE RECENT ACCIDENT IN S AMERICA. I FELT THE ENTIRE CREW PERFORMED VERY WELL AND IN A TIMELY MANNER. I RECEIVED EXCELLENT SUPPORT THROUGHOUT THE MANEUVER FROM BOTH THE CAPT AND SO. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT GND CTLR CONFIRMED THAT THERE HAD BEEN A PRIOR GPWS EARLIER THAT EVENING, A FLT FROM THE RPTR'S COMPANY. IN FACT, THE CTLR SAID THAT THERE HAD BEEN SEVERAL OTHER EVENTS WITH GPWS DURING PREVIOUS OPS. THE TIME FRAME WAS NOT KNOWN. THE ACFT HAD TO HAVE THE ENGS INSPECTED AS THE PF HAD 'FIREWALLED' THE ENGS IN THE CLB MANEUVER, OVERTEMPING THEM IN THE PROCESS. THE ACFT WAS FERRIED BACK TO ATL THE NEXT DAY. THE ENG MANUFACTURER IS STILL STUDYING THE TAPE READOUTS FROM THE FLT DATA RECORDER TO DETERMINE STATUS OF ENGS. THE ENGS WERE OPERATED IN EXCESS PWR FOR A PERIOD OF 8 SECONDS. 'SOMEONE' FROM 'SAFETY' CALLED THE CAPT TO DISCUSS THE SIT. THE ACFT HAD ITS SPOILER-SPD BRAKES DEPLOYED. THE CREW, IN COGNIZANCE OF THE LATEST ACCIDENT IN S AMERICA, DID NOT FAIL TO REMEMBER THE ACFT'S CONFIGN AND RETRACTED THE SPOILERS ON THE MAP. SUPPLEMENTAL INFO FROM ACN 325200: THE FO WAS FLYING THE ACFT. WE WERE 24 MI SE OF ROCKET VOR AND DSNDING TO 2800 FT WHICH WAS THE INITIAL APCH ALT. WE WERE IN LIGHT RIME ICING. WING AND ENG ANTI- ICE WERE ON. PASSING THROUGH 3000 FT, WE HEARD THE GPWS WARNING, 'TERRAIN, TERRAIN.' THE FO FIREWALLED THE ENGS AND INCREASED PITCH TO 20 DEGS (UP). I NOTICED THE TA/VSI WAS PEGGED IN A CLB AND THE RADIO ALTIMETER WAS NOT SHOWING ANY READING. THE TERRAIN WARNING CONTINUED. THE SO SAID, 'KEEP IT CLBING.' PASSING THROUGH 4000-4800 FT, THE TERRAIN WARNING STOPPED. WE LEVELED OFF. DURATION OF THE WARNING WAS APPROX 30 SECONDS. (NOTE: FLT RECORDER DATA SHOWED WE WERE AT FIREWALL PWR FOR 8 SECONDS. IT SEEMED LONGER TO US.) I CALLED HUNTSVILLE APCH AND INFORMED THEM OF WHAT HAPPENED, AND WHY WE WERE AT 4800 FT. I ASKED THEM WHAT THE MINIMUM VECTORING ALT WAS IN OUR AREA. APCH REPLIED, '2800 FT.' THEY ALSO SAID THAT A B737 HAD RPTED A GPWS ALERT EARLIER IN THE EVENING IN THE SAME AREA. THE SO MADE A PA INFORMING THE PAX THAT WE HAD AN ERRONEOUS TERRAIN ALERT. THE FLT ATTENDANTS LATER SAID IT FELT LIKE A NORMAL GAR. DURING THE APCH BRIEFING, I NOTED THE TERRAIN OBSTACLES WERE TWRS LOCATED MOSTLY TO THE NE OF THE ARPT, WITH ONE 1910 FT TWR TO THE SE. ALTHOUGH WE WERE ALL CONFUSED BY A GPWS ALERT AT WHAT WE THOUGHT WAS A SAFE ALT, AN IMMEDIATE TERRAIN AVOIDANCE MANEUVER WAS INITIATED BY THE FO, AND BACKED UP BY THE SO AND I. AFTER LNDG, HUNTSVILLE GND SAID THE AREA SE OF HUNTSVILLE ARPT HAD A HISTORY OF ERRONEOUS GPWS WARNINGS.

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.