Narrative:

Approximately 30 NM southeast of rst airfield while descending out of 9000 ft for 4000 ft at about 8300 ft received a GPWS of too low terrain. Stopped further descent and climbed immediately to 9000 ft. Notified ATC and subsequently completed approach to rst. Callback conversation with reporter revealed the following information: the reporter said that at the time he had entered a steeper than normal descent of about 3000 FPM with a deck angle of about 5 degrees nose down and it was also raining heavily. He said that he knew the terrain in the area and he knew that the GPWS 'terrain' warning was certainly false, but reacted primarily as a training response. He said that after informing the approach controller and xchking the underlying terrain elevation with the controller, the flight crew were able to continue the approach with no problem. They entered the discrepancy into the maintenance log. After reviewing the write up with the maintenance personnel at rst and confirming that the GPWS system was, apparently, now functioning the flight crew went to their next station where they changed to another aircraft. They briefed the flight crew that took this aircraft about the rst incident. The oncoming captain asked if they were in heavy rain at the time of the GPWS warning, according to the reporter. When the reporter responded affirmatively the other captain, apparently, said that he has had this same type of false warning happen to him in heavy rain several times and that it is a characteristic of this installation on the FK10. The other captain has, allegedly, flown other advanced aircraft, but only on this aircraft has he noted this particular phenomenon. The reporter had just flown the B727 and was new to the FK10.

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Original NASA ASRS Text

Title: AN ACR FK10 FLC GOT A GPWS TERRAIN WARNING WHILE DSNDING OUT OF 8300 FT OVER TERRAIN THAT PEAKED AT 1395 FT TO 1602 FT IN THIS GENERAL AREA. ACFT IN RAIN AT THE TIME.

Narrative: APPROX 30 NM SE OF RST AIRFIELD WHILE DSNDING OUT OF 9000 FT FOR 4000 FT AT ABOUT 8300 FT RECEIVED A GPWS OF TOO LOW TERRAIN. STOPPED FURTHER DSCNT AND CLBED IMMEDIATELY TO 9000 FT. NOTIFIED ATC AND SUBSEQUENTLY COMPLETED APCH TO RST. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR SAID THAT AT THE TIME HE HAD ENTERED A STEEPER THAN NORMAL DSCNT OF ABOUT 3000 FPM WITH A DECK ANGLE OF ABOUT 5 DEGS NOSE DOWN AND IT WAS ALSO RAINING HEAVILY. HE SAID THAT HE KNEW THE TERRAIN IN THE AREA AND HE KNEW THAT THE GPWS 'TERRAIN' WARNING WAS CERTAINLY FALSE, BUT REACTED PRIMARILY AS A TRAINING RESPONSE. HE SAID THAT AFTER INFORMING THE APCH CTLR AND XCHKING THE UNDERLYING TERRAIN ELEVATION WITH THE CTLR, THE FLC WERE ABLE TO CONTINUE THE APCH WITH NO PROB. THEY ENTERED THE DISCREPANCY INTO THE MAINT LOG. AFTER REVIEWING THE WRITE UP WITH THE MAINT PERSONNEL AT RST AND CONFIRMING THAT THE GPWS SYS WAS, APPARENTLY, NOW FUNCTIONING THE FLC WENT TO THEIR NEXT STATION WHERE THEY CHANGED TO ANOTHER ACFT. THEY BRIEFED THE FLC THAT TOOK THIS ACFT ABOUT THE RST INCIDENT. THE ONCOMING CAPT ASKED IF THEY WERE IN HVY RAIN AT THE TIME OF THE GPWS WARNING, ACCORDING TO THE RPTR. WHEN THE RPTR RESPONDED AFFIRMATIVELY THE OTHER CAPT, APPARENTLY, SAID THAT HE HAS HAD THIS SAME TYPE OF FALSE WARNING HAPPEN TO HIM IN HVY RAIN SEVERAL TIMES AND THAT IT IS A CHARACTERISTIC OF THIS INSTALLATION ON THE FK10. THE OTHER CAPT HAS, ALLEGEDLY, FLOWN OTHER ADVANCED ACFT, BUT ONLY ON THIS ACFT HAS HE NOTED THIS PARTICULAR PHENOMENON. THE RPTR HAD JUST FLOWN THE B727 AND WAS NEW TO THE FK10.

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.