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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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After seat swap, oncoming first officer observes that TCASII was not displaying, adjusts equipment for operational use, and observes another aircraft 4 mi in trail. Zan thought traffic was 10 mins in trail and descends air carrier from FL350 to FL340.
| Attributes | |
| ACN | 516840 |
| Time | |
| Date | 200107 |
| Day | Mon |
| Local Time Of Day | 0001 To 0600 |
| Place | |
| Locale Reference | airport : anc.airport |
| State Reference | AK |
| Altitude | msl single value : 35000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zan.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B747-400 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zan.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : relief pilot |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 1000 flight time total : 4000 flight time type : 400 |
| ASRS Report | 516840 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Experience | flight time type : 173 |
| ASRS Report | 517232 |
| Supplementary | |
| Problem Areas | ATC Human Performance Aircraft |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Intra Facility Coordination Failure Operational Error |
Narrative:
After seat swap during cruise, other copilot noticed our traffic buttons were not pushed to display TCASII into our CRT's. Once pushed, there was a target at our altitude of FL350, 4 mi behind us. We called on guard to find who it was. Air carrier said it was them. During this, we talked to anchorage on 119.1 and they descended us to FL340. Anchorage said he was told on HF that there was a 10 min separation between us. In reality, there was about 1 min. I'm not sure where the breakdown was with ATC, air crew, etc. Supplemental information from acn 517232: on taking position after crew swap (we were bunkies taking over), I noticed TCASII was not selected on pfd's. Upon selecting traffic display, I noticed a TCASII target co-altitude and 4 mi in trail at FL350. Using 123.45, found out it was air carrier. Called zan on 119.1 to inquire. We were not radar contact yet. They immediately gave us descent to FL340. We were climbed via cpdlc approximately XA45Z to FL350 (while bunkies were on rest break). It was VMC at night. Air carrier was at FL350 prior to our climb. Zan said he was told there was 10 min separation between aircraft (I don't know who told them that).
Original NASA ASRS Text
Title: AFTER SEAT SWAP, ONCOMING FO OBSERVES THAT TCASII WAS NOT DISPLAYING, ADJUSTS EQUIP FOR OPERATIONAL USE, AND OBSERVES ANOTHER ACFT 4 MI IN TRAIL. ZAN THOUGHT TFC WAS 10 MINS IN TRAIL AND DSNDS ACR FROM FL350 TO FL340.
Narrative: AFTER SEAT SWAP DURING CRUISE, OTHER COPLT NOTICED OUR TFC BUTTONS WERE NOT PUSHED TO DISPLAY TCASII INTO OUR CRT'S. ONCE PUSHED, THERE WAS A TARGET AT OUR ALT OF FL350, 4 MI BEHIND US. WE CALLED ON GUARD TO FIND WHO IT WAS. ACR SAID IT WAS THEM. DURING THIS, WE TALKED TO ANCHORAGE ON 119.1 AND THEY DSNDED US TO FL340. ANCHORAGE SAID HE WAS TOLD ON HF THAT THERE WAS A 10 MIN SEPARATION BTWN US. IN REALITY, THERE WAS ABOUT 1 MIN. I'M NOT SURE WHERE THE BREAKDOWN WAS WITH ATC, AIR CREW, ETC. SUPPLEMENTAL INFO FROM ACN 517232: ON TAKING POS AFTER CREW SWAP (WE WERE BUNKIES TAKING OVER), I NOTICED TCASII WAS NOT SELECTED ON PFD'S. UPON SELECTING TFC DISPLAY, I NOTICED A TCASII TARGET CO-ALT AND 4 MI IN TRAIL AT FL350. USING 123.45, FOUND OUT IT WAS ACR. CALLED ZAN ON 119.1 TO INQUIRE. WE WERE NOT RADAR CONTACT YET. THEY IMMEDIATELY GAVE US DSCNT TO FL340. WE WERE CLBED VIA CPDLC APPROX XA45Z TO FL350 (WHILE BUNKIES WERE ON REST BREAK). IT WAS VMC AT NIGHT. ACR WAS AT FL350 PRIOR TO OUR CLB. ZAN SAID HE WAS TOLD THERE WAS 10 MIN SEPARATION BTWN ACFT (I DON'T KNOW WHO TOLD THEM THAT).
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.