 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
ZOA controller experienced operational error at approximately FL330 when air carrier with similar flight numbers initiated climb through occupied altitude.
| Attributes | |
| ACN | 751502 |
| Time | |
| Date | 200708 |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | navaid : swr.vor |
| State Reference | CA |
| Altitude | msl bound lower : 33000 msl bound upper : 34000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zoa.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | Regional Jet CL65 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | climbout : intermediate altitude |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | artcc : zoa.artcc |
| Operator | general aviation : corporate |
| Make Model Name | IAI1124/1124A/Westwind |
| Operating Under FAR Part | Part 91 |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | government : faa |
| Function | controller : radar |
| Qualification | controller : radar |
| Experience | controller military : 5 controller non radar : 10 controller radar : 10 |
| ASRS Report | 751502 |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : required legal separation |
| Independent Detector | atc equipment : conflict alert other controllera |
| Resolutory Action | controller : issued new clearance controller : issued alert |
| Consequence | faa : investigated |
| Miss Distance | horizontal : 24000 vertical : 800 |
| Supplementary | |
| Problem Areas | ATC Human Performance |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
I was working sector 32 in ZOA area north. I was in control of about 15-17 aircraft at the time. I had an air carrier X on frequency and an air carrier Y as well. I had aircraft Z on frequency in level flight at FL340 heading northbound. When air carrier Y checks on frequency I initially climb him to FL310 because of traffic at FL320 in opposite direction. After this conflict was resolved then I climb him to FL330 because of aircraft Z being at FL340. At this time air carrier X has checked in and I initially climb him to FL270 because of traffic sbound at FL280. At this point I had decided to put a j-ring on air carrier Y because of the proximity that he was going to have with aircraft Z. I used the j-ring as a reminder not to climb air carrier Y because of aircraft Z. At this point the conflict between air carrier X and his traffic was resolved; and I issue a clearance for climb to air carrier X to FL350. About 5 mins my radar associate realized that air carrier Y was climbing through FL330 and told me about it. I asked air carrier Y if he was level at FL330 (at this time the data block was indicating FL332) and his reply was 'negative; we were issued a climb to FL350; we are climbing FL350.' I replied; 'negative air carrier Y; you were issued FL330; descend and maintain FL330 immediately.' when the pilot answered back you could hear a loud alarm in the background. At this time separation between air carrier X and aircraft Z was lost.
Original NASA ASRS Text
Title: ZOA CTLR EXPERIENCED OPERROR AT APPROX FL330 WHEN ACR WITH SIMILAR FLT NUMBERS INITIATED CLIMB THROUGH OCCUPIED ALT.
Narrative: I WAS WORKING SECTOR 32 IN ZOA AREA N. I WAS IN CTL OF ABOUT 15-17 ACFT AT THE TIME. I HAD AN ACR X ON FREQ AND AN ACR Y AS WELL. I HAD ACFT Z ON FREQ IN LEVEL FLT AT FL340 HDG NBOUND. WHEN ACR Y CHKS ON FREQ I INITIALLY CLB HIM TO FL310 BECAUSE OF TFC AT FL320 IN OPPOSITE DIRECTION. AFTER THIS CONFLICT WAS RESOLVED THEN I CLB HIM TO FL330 BECAUSE OF ACFT Z BEING AT FL340. AT THIS TIME ACR X HAS CHKED IN AND I INITIALLY CLB HIM TO FL270 BECAUSE OF TFC SBOUND AT FL280. AT THIS POINT I HAD DECIDED TO PUT A J-RING ON ACR Y BECAUSE OF THE PROX THAT HE WAS GOING TO HAVE WITH ACFT Z. I USED THE J-RING AS A REMINDER NOT TO CLB ACR Y BECAUSE OF ACFT Z. AT THIS POINT THE CONFLICT BTWN ACR X AND HIS TFC WAS RESOLVED; AND I ISSUE A CLRNC FOR CLB TO ACR X TO FL350. ABOUT 5 MINS MY RADAR ASSOCIATE REALIZED THAT ACR Y WAS CLBING THROUGH FL330 AND TOLD ME ABOUT IT. I ASKED ACR Y IF HE WAS LEVEL AT FL330 (AT THIS TIME THE DATA BLOCK WAS INDICATING FL332) AND HIS REPLY WAS 'NEGATIVE; WE WERE ISSUED A CLB TO FL350; WE ARE CLBING FL350.' I REPLIED; 'NEGATIVE ACR Y; YOU WERE ISSUED FL330; DSND AND MAINTAIN FL330 IMMEDIATELY.' WHEN THE PLT ANSWERED BACK YOU COULD HEAR A LOUD ALARM IN THE BACKGROUND. AT THIS TIME SEPARATION BTWN ACR X AND ACFT Z WAS LOST.
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.