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|
Attributes | |
ACN | 434515 |
Time | |
Date | 199902 |
Day | Tue |
Local Time Of Day | 1801 To 2400 |
Place | |
Locale Reference | airport : fai.airport |
State Reference | AK |
Altitude | msl bound lower : 4100 msl bound upper : 6000 |
Environment | |
Flight Conditions | VMC |
Light | Night |
Aircraft 1 | |
Controlling Facilities | tracon : fai.tracon tower : dfw.tower |
Operator | common carrier : air carrier |
Make Model Name | B737 Undifferentiated or Other Model |
Operating Under FAR Part | Part 121 |
Navigation In Use | Other |
Flight Phase | descent : vacating altitude |
Flight Plan | IFR |
Person 1 | |
Affiliation | company : air carrier |
Function | flight crew : captain oversight : pic |
Qualification | pilot : atp |
Experience | flight time last 90 days : 120 flight time total : 14500 |
ASRS Report | 434515 |
Person 2 | |
Affiliation | company : air carrier |
Function | flight crew : first officer |
Qualification | pilot : instrument pilot : commercial pilot : multi engine |
Events | |
Anomaly | altitude deviation : excursion from assigned altitude inflight encounter other other anomaly other |
Independent Detector | aircraft equipment : gpws |
Resolutory Action | flight crew : exited adverse environment |
Consequence | faa : reviewed incident with flight crew |
Supplementary | |
Problem Areas | ATC Human Performance Airspace Structure |
Primary Problem | Airspace Structure |
Air Traffic Incident | other |
Narrative:
Flight was scheduled from barrow, ak, to fairbanks, ak. The temperature on the ground at fai was -40 degrees C. Fai approach control was controling the flight. We were on descent and had received clearance to 4000 ft MSL. The MSA published on the commercial charts is 4300 ft MSL. We had just received a turn off of the airway (299 degree radial of fai). Passing 4100 ft MSL, we received a mode 2 'excessive terrain closure rate' GPWS warning. 'Terrain, terrain' followed shortly by 'pull up, pull up.' we executed a maximum go around power climb to 6000 ft MSL. Airspeed during descent was 250 KIAS. The warning silenced and we notified fai approach. They did not seem concerned. The lowest radio altimeter during the GPWS was 1100 ft. The highest point within 5 mi of our aircraft was murphy dome at 2970 ft MSL. During day VFR flight into fai from the north, it is not unusual to get this warning while on a visual approach because we descend below the MSA. During a dark night, even in VFR conditions this warning was very disconcerting. I am sure a major factor was the very cold temperatures in the fai area, and associated altimeter errors. Suggest MSA, MVA and approach altitudes be adjusted upward to compensate for extreme temperatures. A simple chart for use by flcs and ATC controllers needs to be developed and implemented.
Original NASA ASRS Text
Title: FLC OF A B737 AT FAI RESPONDS TO GPWS WHILE BEING VECTORED FOR AN APCH.
Narrative: FLT WAS SCHEDULED FROM BARROW, AK, TO FAIRBANKS, AK. THE TEMP ON THE GND AT FAI WAS -40 DEGS C. FAI APCH CTL WAS CTLING THE FLT. WE WERE ON DSCNT AND HAD RECEIVED CLRNC TO 4000 FT MSL. THE MSA PUBLISHED ON THE COMMERCIAL CHARTS IS 4300 FT MSL. WE HAD JUST RECEIVED A TURN OFF OF THE AIRWAY (299 DEG RADIAL OF FAI). PASSING 4100 FT MSL, WE RECEIVED A MODE 2 'EXCESSIVE TERRAIN CLOSURE RATE' GPWS WARNING. 'TERRAIN, TERRAIN' FOLLOWED SHORTLY BY 'PULL UP, PULL UP.' WE EXECUTED A MAX GAR PWR CLB TO 6000 FT MSL. AIRSPD DURING DSCNT WAS 250 KIAS. THE WARNING SILENCED AND WE NOTIFIED FAI APCH. THEY DID NOT SEEM CONCERNED. THE LOWEST RADIO ALTIMETER DURING THE GPWS WAS 1100 FT. THE HIGHEST POINT WITHIN 5 MI OF OUR ACFT WAS MURPHY DOME AT 2970 FT MSL. DURING DAY VFR FLT INTO FAI FROM THE N, IT IS NOT UNUSUAL TO GET THIS WARNING WHILE ON A VISUAL APCH BECAUSE WE DSND BELOW THE MSA. DURING A DARK NIGHT, EVEN IN VFR CONDITIONS THIS WARNING WAS VERY DISCONCERTING. I AM SURE A MAJOR FACTOR WAS THE VERY COLD TEMPS IN THE FAI AREA, AND ASSOCIATED ALTIMETER ERRORS. SUGGEST MSA, MVA AND APCH ALTS BE ADJUSTED UPWARD TO COMPENSATE FOR EXTREME TEMPS. A SIMPLE CHART FOR USE BY FLCS AND ATC CTLRS NEEDS TO BE DEVELOPED AND IMPLEMENTED.
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.