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Flight crew of an medium large transport took evasive action by climbing in response to a GPWS alert during descent for an instrument approach.
| Attributes | |
| ACN | 327908 |
| Time | |
| Date | 199602 |
| Day | Thu |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : avp |
| State Reference | PA |
| Altitude | msl bound lower : 3500 msl bound upper : 4500 |
| Environment | |
| Flight Conditions | IMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : avp |
| Operator | common carrier : air carrier |
| Make Model Name | Fokker 100 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | descent other |
| Route In Use | enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | other other : other pilot : instrument pilot : flight engineer pilot : atp pilot : commercial |
| Experience | flight time last 90 days : 100 flight time total : 11800 flight time type : 4000 |
| ASRS Report | 327908 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | flight crew : exited adverse environment flight crew : took evasive action |
| Consequence | faa : reviewed incident with flight crew Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
While on a vector downwind for runway 22 at avp on assigned descent from 4000 ft to 3300 ft (5-7 NM northeast of avp), received GPWS terrain alert. I disconnected autoplt and aggressively maneuvered the aircraft into a climb, topping out about 4500 ft on recovery. Notified ATC of situation. ATC stated that this problem has occurred previously. Minimum safe vector altitude was 4000 ft for ATC. Mountain was snow covered. Either the fokker 100 has equipment problems or ATC is vectoring too close to the envelope of the GPWS. Avp does vector close to the airport and mountain east of the field. Maybe this should be revised. The FK100 does have some history of problems with the radar altimeter mounting, and I have seen alerts before caused by the reflection of ice/snow. This aircraft was also written up for a radar altimeter problem the next day. Both these items should be looked into and crews made aware of possible problems. The last thing we need is a lot of false GPWS alerts or crews not believing an alert because there are too many false ones.
Original NASA ASRS Text
Title: FLC OF AN MLG TOOK EVASIVE ACTION BY CLBING IN RESPONSE TO A GPWS ALERT DURING DSCNT FOR AN INST APCH.
Narrative: WHILE ON A VECTOR DOWNWIND FOR RWY 22 AT AVP ON ASSIGNED DSCNT FROM 4000 FT TO 3300 FT (5-7 NM NE OF AVP), RECEIVED GPWS TERRAIN ALERT. I DISCONNECTED AUTOPLT AND AGGRESSIVELY MANEUVERED THE ACFT INTO A CLB, TOPPING OUT ABOUT 4500 FT ON RECOVERY. NOTIFIED ATC OF SIT. ATC STATED THAT THIS PROB HAS OCCURRED PREVIOUSLY. MINIMUM SAFE VECTOR ALT WAS 4000 FT FOR ATC. MOUNTAIN WAS SNOW COVERED. EITHER THE FOKKER 100 HAS EQUIP PROBS OR ATC IS VECTORING TOO CLOSE TO THE ENVELOPE OF THE GPWS. AVP DOES VECTOR CLOSE TO THE ARPT AND MOUNTAIN E OF THE FIELD. MAYBE THIS SHOULD BE REVISED. THE FK100 DOES HAVE SOME HISTORY OF PROBS WITH THE RADAR ALTIMETER MOUNTING, AND I HAVE SEEN ALERTS BEFORE CAUSED BY THE REFLECTION OF ICE/SNOW. THIS ACFT WAS ALSO WRITTEN UP FOR A RADAR ALTIMETER PROB THE NEXT DAY. BOTH THESE ITEMS SHOULD BE LOOKED INTO AND CREWS MADE AWARE OF POSSIBLE PROBS. THE LAST THING WE NEED IS A LOT OF FALSE GPWS ALERTS OR CREWS NOT BELIEVING AN ALERT BECAUSE THERE ARE TOO MANY FALSE ONES.
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.