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Flight crew of a B727 took the appropriate escape maneuver by stopping their descent and climbing in response to a GPWS warning. Even though the aircraft was above the MVA, the rate of descent and high rising terrain in front of their aircraft could have caused this warning.
| Attributes | |
| ACN | 355364 |
| Time | |
| Date | 199612 |
| Day | Thu |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : eca airport : oak |
| State Reference | CA |
| Altitude | msl bound lower : 3400 msl bound upper : 3900 |
| Environment | |
| Flight Conditions | IMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : oak |
| Operator | common carrier : air carrier |
| Make Model Name | B727 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | descent other |
| Route In Use | enroute : on vectors enroute airway : oak |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : second officer |
| Qualification | pilot : atp pilot : flight engineer |
| Experience | flight time last 90 days : 45 flight time total : 2900 flight time type : 250 |
| ASRS Report | 355364 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | other anomaly other other spatial deviation |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | flight crew : took evasive action |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
On descent to 3200 ft MSL (MVA) at approximately 3400 ft, we received a GPWS warning 'too low, terrain.' flight crew immediately performed escape maneuver. At approximately 3800- 3900 ft, and in VMC, we started our descent back down to 3200 ft and informed approach control of our situation. Aircraft rate of descent was approximately 700 FPM. We believe that even though we were above MVA, the combination of rising terrain and aircraft descent rate may have caused the GPWS to give its warning. Radar altitude was 1600-1800 ft AGL at time of warning.
Original NASA ASRS Text
Title: FLC OF A B727 TOOK THE APPROPRIATE ESCAPE MANEUVER BY STOPPING THEIR DSCNT AND CLBING IN RESPONSE TO A GPWS WARNING. EVEN THOUGH THE ACFT WAS ABOVE THE MVA, THE RATE OF DSCNT AND HIGH RISING TERRAIN IN FRONT OF THEIR ACFT COULD HAVE CAUSED THIS WARNING.
Narrative: ON DSCNT TO 3200 FT MSL (MVA) AT APPROX 3400 FT, WE RECEIVED A GPWS WARNING 'TOO LOW, TERRAIN.' FLC IMMEDIATELY PERFORMED ESCAPE MANEUVER. AT APPROX 3800- 3900 FT, AND IN VMC, WE STARTED OUR DSCNT BACK DOWN TO 3200 FT AND INFORMED APCH CTL OF OUR SIT. ACFT RATE OF DSCNT WAS APPROX 700 FPM. WE BELIEVE THAT EVEN THOUGH WE WERE ABOVE MVA, THE COMBINATION OF RISING TERRAIN AND ACFT DSCNT RATE MAY HAVE CAUSED THE GPWS TO GIVE ITS WARNING. RADAR ALT WAS 1600-1800 FT AGL AT TIME OF WARNING.
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.