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An ATR72 flight crew leaves their assigned altitude during an approach to avl runway 34 ILS when receiving a GPWS warning. In doing so, they incur a potential conflict with an air holding C172.
| Attributes | |
| ACN | 393435 |
| Time | |
| Date | 199802 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : bra airport : avl |
| State Reference | NC |
| Altitude | msl bound lower : 5100 msl bound upper : 5500 |
| Environment | |
| Flight Conditions | IMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : avl tower : pos |
| Operator | common carrier : air carrier |
| Make Model Name | ATR 72 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other |
| Flight Phase | descent : approach |
| Route In Use | arrival other enroute : on vectors |
| Flight Plan | IFR |
| Aircraft 2 | |
| Make Model Name | Skyhawk 172/Cutlass 172 |
| Operating Under FAR Part | Part 91 |
| Flight Phase | other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : cfi pilot : commercial |
| Experience | flight time last 90 days : 250 flight time total : 1700 flight time type : 800 |
| ASRS Report | 393435 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 250 flight time total : 24000 flight time type : 2500 |
| ASRS Report | 393168 |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude conflict : airborne less severe non adherence : required legal separation non adherence : clearance other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : exited adverse environment flight crew : returned to intended course or assigned course |
| Consequence | Other |
| Miss Distance | horizontal : 15000 vertical : 600 |
| Supplementary | |
| Air Traffic Incident | Pilot Deviation other |
| Situations | |
| ATC Facility | procedure or policy : unspecified |
Narrative:
We were assigned 5100 ft MSL, on a radar vector to an ILS approach to runway 34 to asheville, nc, regional. We were advised of a skyhawk holding at the broad river NDB at 6100 ft MSL. Around freez intersection we received the GPWS warning, 'terrain, terrain.' knowing where we were and that a tower existed on top of terrain 4091 ft we hesitated due to the other aircraft holding and occupying airspace we needed but when the warning didn't go away, rather than selecting maximum power, maximum climb, we started a gradual climb, 400-500 FPM, notified ATC: 'initiating GPWS climb.' we then received a TCASII TA not an RA that did not come as a surprise. We were in IMC the whole time. As soon as the GPWS warning extinguished, we returned to our assigned altitude of 5100 ft MSL. We climbed to 5500 ft MSL during the conflict. Being in IMC, we could not see the terrain and had no choice but to respond to the GPWS warning. ATC gave us a heading after we advised we were climbing to avoid traffic. If I had to do it all over I would do nothing different. We acted with common sense and per company procedures. I feel that the skyhawk should have been at a higher altitude since GPWS warnings are common along that route, and its mission appeared to be training only which could be conducted at a higher altitude. Supplemental information from acn 393168: I recommend higher vectoring altitude due to terrain and tower located near 'freez' intersection.
Original NASA ASRS Text
Title: AN ATR72 FLC LEAVES THEIR ASSIGNED ALT DURING AN APCH TO AVL RWY 34 ILS WHEN RECEIVING A GPWS WARNING. IN DOING SO, THEY INCUR A POTENTIAL CONFLICT WITH AN AIR HOLDING C172.
Narrative: WE WERE ASSIGNED 5100 FT MSL, ON A RADAR VECTOR TO AN ILS APCH TO RWY 34 TO ASHEVILLE, NC, REGIONAL. WE WERE ADVISED OF A SKYHAWK HOLDING AT THE BROAD RIVER NDB AT 6100 FT MSL. AROUND FREEZ INTXN WE RECEIVED THE GPWS WARNING, 'TERRAIN, TERRAIN.' KNOWING WHERE WE WERE AND THAT A TWR EXISTED ON TOP OF TERRAIN 4091 FT WE HESITATED DUE TO THE OTHER ACFT HOLDING AND OCCUPYING AIRSPACE WE NEEDED BUT WHEN THE WARNING DIDN'T GO AWAY, RATHER THAN SELECTING MAX PWR, MAX CLB, WE STARTED A GRADUAL CLB, 400-500 FPM, NOTIFIED ATC: 'INITIATING GPWS CLB.' WE THEN RECEIVED A TCASII TA NOT AN RA THAT DID NOT COME AS A SURPRISE. WE WERE IN IMC THE WHOLE TIME. AS SOON AS THE GPWS WARNING EXTINGUISHED, WE RETURNED TO OUR ASSIGNED ALT OF 5100 FT MSL. WE CLBED TO 5500 FT MSL DURING THE CONFLICT. BEING IN IMC, WE COULD NOT SEE THE TERRAIN AND HAD NO CHOICE BUT TO RESPOND TO THE GPWS WARNING. ATC GAVE US A HEADING AFTER WE ADVISED WE WERE CLBING TO AVOID TFC. IF I HAD TO DO IT ALL OVER I WOULD DO NOTHING DIFFERENT. WE ACTED WITH COMMON SENSE AND PER COMPANY PROCS. I FEEL THAT THE SKYHAWK SHOULD HAVE BEEN AT A HIGHER ALT SINCE GPWS WARNINGS ARE COMMON ALONG THAT RTE, AND ITS MISSION APPEARED TO BE TRAINING ONLY WHICH COULD BE CONDUCTED AT A HIGHER ALT. SUPPLEMENTAL INFO FROM ACN 393168: I RECOMMEND HIGHER VECTORING ALT DUE TO TERRAIN AND TWR LOCATED NEAR 'FREEZ' INTXN.
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.