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ATCT VHF communication failure results in uncontrolled traffic. Traffic conflicts and terrain clearance issues result until communication is re-established.
| Attributes | |
| ACN | 693753 |
| Time | |
| Date | 200604 |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : phx.airport |
| State Reference | AZ |
| Altitude | msl single value : 3000 |
| Environment | |
| Flight Conditions | Marginal |
| Weather Elements | other |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : p50.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | B737-300 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | descent : approach |
| Route In Use | arrival : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Experience | flight time last 90 days : 250 flight time total : 11000 flight time type : 2400 |
| ASRS Report | 693753 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Experience | flight time last 90 days : 120 flight time total : 14000 flight time type : 12000 |
| ASRS Report | 693754 |
| Events | |
| Anomaly | conflict : airborne critical other anomaly other other spatial deviation |
| Independent Detector | aircraft equipment : gpws aircraft equipment : tcas other controllera other flight crewa other flight crewb |
| Resolutory Action | controller : issued new clearance flight crew : took precautionary avoidance action other |
| Supplementary | |
| Problem Areas | ATC Facility |
| Primary Problem | ATC Facility |
| Situations | |
| ATC Facility | communication equipment : phx.tower |
Narrative:
Base leg vector to runway 25L at phx. Flew through the localizer without being told to turn final. Other traffic passed opposite direction overhead estimated less than 1000 ft higher. These generated a query by us to ATC; who did not respond until after multiple calls by us. When ATC responded; they said they 'had a frequency go out;' and gave us a corrective vector to the downwind this time for runway 26 at phx. Headed eastbound at 3000 ft MSL into rising terrain. We again became concerned as 'yellow' terrain on GPWS terrain map approached. We also saw the terrain visually. While attempting to query ATC again; we got no answer; and began a climbing left to the west to avoid terrain. During this maneuver; ATC regained contact with us and had us level off at 5000 ft MSL. This time we were vectored to final for runway 25L again; and landed uneventfully. The cause was ATC radio transmission failure. Contributing factors to the safe outcome were the availability to the pilots of egpws terrain map; that allowed us to take corrective action in advance of the triggering of a warning; and the availability of traffic. Finally; it was invaluable to have a second pilot; the PNF; to help assess the situation and aid in decision making. Hopefully; ATC was clearing traffic from our area; in advance of our maneuvering; due to the NORDO situation.
Original NASA ASRS Text
Title: ATCT VHF COM FAILURE RESULTS IN UNCTLED TFC. TFC CONFLICTS AND TERRAIN CLRNC ISSUES RESULT UNTIL COM IS RE-ESTABLISHED.
Narrative: BASE LEG VECTOR TO RWY 25L AT PHX. FLEW THROUGH THE LOC WITHOUT BEING TOLD TO TURN FINAL. OTHER TFC PASSED OPPOSITE DIRECTION OVERHEAD ESTIMATED LESS THAN 1000 FT HIGHER. THESE GENERATED A QUERY BY US TO ATC; WHO DID NOT RESPOND UNTIL AFTER MULTIPLE CALLS BY US. WHEN ATC RESPONDED; THEY SAID THEY 'HAD A FREQ GO OUT;' AND GAVE US A CORRECTIVE VECTOR TO THE DOWNWIND THIS TIME FOR RWY 26 AT PHX. HEADED EBOUND AT 3000 FT MSL INTO RISING TERRAIN. WE AGAIN BECAME CONCERNED AS 'YELLOW' TERRAIN ON GPWS TERRAIN MAP APCHED. WE ALSO SAW THE TERRAIN VISUALLY. WHILE ATTEMPTING TO QUERY ATC AGAIN; WE GOT NO ANSWER; AND BEGAN A CLBING L TO THE W TO AVOID TERRAIN. DURING THIS MANEUVER; ATC REGAINED CONTACT WITH US AND HAD US LEVEL OFF AT 5000 FT MSL. THIS TIME WE WERE VECTORED TO FINAL FOR RWY 25L AGAIN; AND LANDED UNEVENTFULLY. THE CAUSE WAS ATC RADIO XMISSION FAILURE. CONTRIBUTING FACTORS TO THE SAFE OUTCOME WERE THE AVAILABILITY TO THE PLTS OF EGPWS TERRAIN MAP; THAT ALLOWED US TO TAKE CORRECTIVE ACTION IN ADVANCE OF THE TRIGGERING OF A WARNING; AND THE AVAILABILITY OF TFC. FINALLY; IT WAS INVALUABLE TO HAVE A SECOND PLT; THE PNF; TO HELP ASSESS THE SITUATION AND AID IN DECISION MAKING. HOPEFULLY; ATC WAS CLRING TFC FROM OUR AREA; IN ADVANCE OF OUR MANEUVERING; DUE TO THE NORDO SITUATION.
Data retrieved from NASA's ASRS site as of January 2009 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.