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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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Air carrier medium large transport gets a GPWS alert at 7500 ft over terrain with less than 1000 ft elevation. Climbs to 13000 ft to clear the alert. Advised ATC of altitude deviation. Aircraft had been in descent through rain with nearby thunderstorms. Possible false warning due to induced propagation from rain drops.
| Attributes | |
| ACN | 363769 |
| Time | |
| Date | 199703 |
| Day | Tue |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : bna |
| State Reference | TN |
| Altitude | msl bound lower : 7500 msl bound upper : 13000 |
| Environment | |
| Flight Conditions | IMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : bna artcc : zid |
| Operator | common carrier : air carrier |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Flight Phase | climbout : intermediate altitude descent other |
| Route In Use | arrival other enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 210 flight time total : 4000 flight time type : 1035 |
| ASRS Report | 363769 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude altitude deviation : undershoot inflight encounter : weather non adherence : clearance other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified |
| Resolutory Action | flight crew : declared emergency flight crew : exited adverse environment other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
We were in the descent out of 9000 ft MSL for 6000 ft MSL when we got the alert 'too low, terrain, too low, terrain.' so we did the procedure and advised ATC of our alert and climbed up to 13000 ft and leveled off. At the time there was rain and thunderstorms in the area. ATC advised us that no conflict had occurred and we continued the flight.
Original NASA ASRS Text
Title: ACR MLG GETS A GPWS ALERT AT 7500 FT OVER TERRAIN WITH LESS THAN 1000 FT ELEVATION. CLBS TO 13000 FT TO CLR THE ALERT. ADVISED ATC OF ALTDEV. ACFT HAD BEEN IN DSCNT THROUGH RAIN WITH NEARBY TSTMS. POSSIBLE FALSE WARNING DUE TO INDUCED PROPAGATION FROM RAIN DROPS.
Narrative: WE WERE IN THE DSCNT OUT OF 9000 FT MSL FOR 6000 FT MSL WHEN WE GOT THE ALERT 'TOO LOW, TERRAIN, TOO LOW, TERRAIN.' SO WE DID THE PROC AND ADVISED ATC OF OUR ALERT AND CLBED UP TO 13000 FT AND LEVELED OFF. AT THE TIME THERE WAS RAIN AND TSTMS IN THE AREA. ATC ADVISED US THAT NO CONFLICT HAD OCCURRED AND WE CONTINUED THE FLT.
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.