Narrative:

Descending at 1800 FPM to 6000 ft 210 KTS spoilers and slats extended and engine and airfoil anti-ice on. Passing 7000 ft GPWS light illuminated with terrain aural warning. The first officer initiated climb, I called approach and told them, 'air carrier XXX climbing because of ground proximity warning.' because of the noise from the aural warning, I could barely make out the response. I believe he told us that the minimum safe altitude was 2300 ft and we were clear of traffic or clear to climb. Captain and first officer altimeters indicated 6600 and standby 7200, all climbing. Radio altitude was blank but then flickered momentarily as if just tested. Passing 9000 ft I turned GPWS switch to override, but the too low terrain and too low gear warning continued. Approach called. Because I could not understand what he was saying, I told him to stand by. At about 9500 ft, I told the first officer to lower the landing gear, this finally stopped the warnings. The flight terminated to an uneventful approach and landing. 2 observations: first, modern aircraft have all sorts of warnings. They are too loud and there ought to be a way to readily silence them when appropriate. The loudness created confusion, made it harder to communicate in the cockpit and with approach control. Second, the first officer and I were surprised at how startling the terrain warning can be in IMC. We were over familiar terrain well above MDA with an obvious false warning, yet maybe because of the recent cali accident, the pucker factor was out of proportion to any real danger. Callback conversation with reporter revealed the following information: the reporter stated the crew was wearing an ear piece type ear plug headset. Even so, with the loudness of the warning the controller was hard to understand. The reporter wanted to emphasize the psychological trauma that occurs when the warning goes off so loudly that it is disconcerting. The reporter stated his copilot is excellent and yet he forgot to lower the speed brakes on level off. He said, this arrival they have flown hundreds of times, many as a pilot team. They knew the warning was false. Still the GPWS caused an adrenaline rush that was beyond anticipated proportions. The reporter said he could relate to the responsiveness and sensitivities of the cali pilots in their forgetting the speed brakes. This analyst asked if there was any reason he could think of the speed brakes should not retract with throttle applications of go around proportions. He said he thought that would be a good idea. That is what occurs when the spoilers are armed for the automatic deployment on landing. He stated the GPWS was probably triggered by the faulty radio altimeter.

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Original NASA ASRS Text

Title: DSNDING THROUGH 7000 FT THE GPWS FALSE WARNING OCCURRED. WARNINGS ARE TOO LOUD AND SHOULD BE ABLE TO CANCEL. SPD BRAKES SHOULD RETRACT WHEN PWR IS APPLIED.

Narrative: DSNDING AT 1800 FPM TO 6000 FT 210 KTS SPOILERS AND SLATS EXTENDED AND ENG AND AIRFOIL ANTI-ICE ON. PASSING 7000 FT GPWS LIGHT ILLUMINATED WITH TERRAIN AURAL WARNING. THE FO INITIATED CLB, I CALLED APCH AND TOLD THEM, 'ACR XXX CLBING BECAUSE OF GND PROX WARNING.' BECAUSE OF THE NOISE FROM THE AURAL WARNING, I COULD BARELY MAKE OUT THE RESPONSE. I BELIEVE HE TOLD US THAT THE MINIMUM SAFE ALT WAS 2300 FT AND WE WERE CLR OF TFC OR CLR TO CLB. CAPT AND FO ALTIMETERS INDICATED 6600 AND STANDBY 7200, ALL CLBING. RADIO ALT WAS BLANK BUT THEN FLICKERED MOMENTARILY AS IF JUST TESTED. PASSING 9000 FT I TURNED GPWS SWITCH TO OVERRIDE, BUT THE TOO LOW TERRAIN AND TOO LOW GEAR WARNING CONTINUED. APCH CALLED. BECAUSE I COULD NOT UNDERSTAND WHAT HE WAS SAYING, I TOLD HIM TO STAND BY. AT ABOUT 9500 FT, I TOLD THE FO TO LOWER THE LNDG GEAR, THIS FINALLY STOPPED THE WARNINGS. THE FLT TERMINATED TO AN UNEVENTFUL APCH AND LNDG. 2 OBSERVATIONS: FIRST, MODERN ACFT HAVE ALL SORTS OF WARNINGS. THEY ARE TOO LOUD AND THERE OUGHT TO BE A WAY TO READILY SILENCE THEM WHEN APPROPRIATE. THE LOUDNESS CREATED CONFUSION, MADE IT HARDER TO COMMUNICATE IN THE COCKPIT AND WITH APCH CTL. SECOND, THE FO AND I WERE SURPRISED AT HOW STARTLING THE TERRAIN WARNING CAN BE IN IMC. WE WERE OVER FAMILIAR TERRAIN WELL ABOVE MDA WITH AN OBVIOUS FALSE WARNING, YET MAYBE BECAUSE OF THE RECENT CALI ACCIDENT, THE PUCKER FACTOR WAS OUT OF PROPORTION TO ANY REAL DANGER. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE CREW WAS WEARING AN EAR PIECE TYPE EAR PLUG HEADSET. EVEN SO, WITH THE LOUDNESS OF THE WARNING THE CTLR WAS HARD TO UNDERSTAND. THE RPTR WANTED TO EMPHASIZE THE PSYCHOLOGICAL TRAUMA THAT OCCURS WHEN THE WARNING GOES OFF SO LOUDLY THAT IT IS DISCONCERTING. THE RPTR STATED HIS COPLT IS EXCELLENT AND YET HE FORGOT TO LOWER THE SPD BRAKES ON LEVEL OFF. HE SAID, THIS ARR THEY HAVE FLOWN HUNDREDS OF TIMES, MANY AS A PLT TEAM. THEY KNEW THE WARNING WAS FALSE. STILL THE GPWS CAUSED AN ADRENALINE RUSH THAT WAS BEYOND ANTICIPATED PROPORTIONS. THE RPTR SAID HE COULD RELATE TO THE RESPONSIVENESS AND SENSITIVITIES OF THE CALI PLTS IN THEIR FORGETTING THE SPD BRAKES. THIS ANALYST ASKED IF THERE WAS ANY REASON HE COULD THINK OF THE SPD BRAKES SHOULD NOT RETRACT WITH THROTTLE APPLICATIONS OF GAR PROPORTIONS. HE SAID HE THOUGHT THAT WOULD BE A GOOD IDEA. THAT IS WHAT OCCURS WHEN THE SPOILERS ARE ARMED FOR THE AUTOMATIC DEPLOYMENT ON LNDG. HE STATED THE GPWS WAS PROBABLY TRIGGERED BY THE FAULTY RADIO ALTIMETER.

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.