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Air carrier medium large transport with mode C inoperative is told to take evasive action by ZLC controller due to conflicting traffic.
| Attributes | |
| ACN | 140796 |
| Time | |
| Date | 199003 |
| Day | Fri |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : bce |
| State Reference | UT |
| Altitude | msl bound lower : 33000 msl bound upper : 35000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zlc |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp pilot : flight engineer |
| Experience | flight time last 90 days : 150 flight time total : 2400 flight time type : 680 |
| ASRS Report | 140796 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 150 flight time total : 10000 flight time type : 700 |
| ASRS Report | 141366 |
| Events | |
| Anomaly | aircraft equipment problem : less severe conflict : airborne less severe other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance |
| Consequence | Other |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Deviation Intra Facility Coordination Failure |
Narrative:
Aircraft was dispatched with one transponder mode C inoperative. After takeoff, we discovered remaining mode C was also inoperative (confirmed by conversation with controller). During cruise at FL350, ZLC assigned a descent to FL330. 10-15 mins later (can't recall if it was the same controller) center frantically issued an immediate left turn (about 70 degree) and immediate climb to FL350. He issued similar instructions to another carrier. When evasive action was complete, the controller advised us as to our altitude prior to the conflict. In the future, it may be advisable to tell each controller (not just the first one) about any equipment malfunctions.
Original NASA ASRS Text
Title: ACR MLG WITH MODE C INOPERATIVE IS TOLD TO TAKE EVASIVE ACTION BY ZLC CTLR DUE TO CONFLICTING TRAFFIC.
Narrative: ACFT WAS DISPATCHED WITH ONE XPONDER MODE C INOP. AFTER TKOF, WE DISCOVERED REMAINING MODE C WAS ALSO INOP (CONFIRMED BY CONVERSATION WITH CTLR). DURING CRUISE AT FL350, ZLC ASSIGNED A DSCNT TO FL330. 10-15 MINS LATER (CAN'T RECALL IF IT WAS THE SAME CTLR) CENTER FRANTICALLY ISSUED AN IMMEDIATE LEFT TURN (ABOUT 70 DEG) AND IMMEDIATE CLIMB TO FL350. HE ISSUED SIMILAR INSTRUCTIONS TO ANOTHER CARRIER. WHEN EVASIVE ACTION WAS COMPLETE, THE CTLR ADVISED US AS TO OUR ALT PRIOR TO THE CONFLICT. IN THE FUTURE, IT MAY BE ADVISABLE TO TELL EACH CTLR (NOT JUST THE FIRST ONE) ABOUT ANY EQUIPMENT MALFUNCTIONS.
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.