Narrative:

This incident involved an airspace deviation where an aircraft entered another control facility's (tokyo center) airspace at an altitude other than what was coordinated. The incident involved air carrier X, a widebody transport, en route from pgsn to rjaa via A337. The aircraft was transferred to oak ARTCC from guam cerap, proceeding pgsn direct tegod A337 climbing to cross 20 degree north latitude at FL390. The controller that I relieved took the transfer and wrote the wrong altitude on the flight progress strip. He indicated that air carrier X was climbing to cross 20 degree north latitude at FL350. At about this time, I was sent to relieve this controller so that he could have a break. During the relief briefing, when we discussed this aircraft, the controller informed me that air carrier X was climbing to cross 20 north latitude at FL350, just to make sure I had it correctly, I questioned the altitude climbing to and again, I was told that air carrier X was climbing to cross 20 degree north at FL350. After I assumed the sector, I called tokyo center with a transfer on air carrier X at tegod time X17Z at FL350. Due to the short distance between guam's airspace and tokyo's airspace, many times oak ARTCC does not receive any progress reports. So the first point that the pilot reported was tegod. At X34Z, tokyo center called to verify the assigned altitude of air carrier X as FL350 and indicated that the aircraft was at FL390. I then called guam cerap to verify the assigned altitude. The controller said that the aircraft was assigned to cross 20 degree north latitude at FL390. At this time, I called tokyo and advised them that the air carrier X was in fact assigned FL390. At the time of the incident, sector OC5 at oak ARTCC was extremely busy with heavy traffic (25 or more aircraft) and a very high complexity level. The corrective action would have been to have the first controller indicate the proper altitude on the flight progress strip.

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Original NASA ASRS Text

Title: ACR ENTERS ADJACENT FACILITY AIRSPACE AT WRONG ALT IN OCEANIC NON RADAR ENVIRONMENT

Narrative: THIS INCIDENT INVOLVED AN AIRSPACE DEV WHERE AN ACFT ENTERED ANOTHER CTL FACILITY'S (TOKYO CTR) AIRSPACE AT AN ALT OTHER THAN WHAT WAS COORDINATED. THE INCIDENT INVOLVED ACR X, A WDB, ENRTE FROM PGSN TO RJAA VIA A337. THE ACFT WAS TRANSFERRED TO OAK ARTCC FROM GUAM CERAP, PROCEEDING PGSN DIRECT TEGOD A337 CLBING TO CROSS 20 DEG N LATITUDE AT FL390. THE CTLR THAT I RELIEVED TOOK THE TRANSFER AND WROTE THE WRONG ALT ON THE FLT PROGRESS STRIP. HE INDICATED THAT ACR X WAS CLBING TO CROSS 20 DEG N LATITUDE AT FL350. AT ABOUT THIS TIME, I WAS SENT TO RELIEVE THIS CTLR SO THAT HE COULD HAVE A BREAK. DURING THE RELIEF BRIEFING, WHEN WE DISCUSSED THIS ACFT, THE CTLR INFORMED ME THAT ACR X WAS CLBING TO CROSS 20 N LATITUDE AT FL350, JUST TO MAKE SURE I HAD IT CORRECTLY, I QUESTIONED THE ALT CLBING TO AND AGAIN, I WAS TOLD THAT ACR X WAS CLBING TO CROSS 20 DEG N AT FL350. AFTER I ASSUMED THE SECTOR, I CALLED TOKYO CTR WITH A TRANSFER ON ACR X AT TEGOD TIME X17Z AT FL350. DUE TO THE SHORT DISTANCE BTWN GUAM'S AIRSPACE AND TOKYO'S AIRSPACE, MANY TIMES OAK ARTCC DOES NOT RECEIVE ANY PROGRESS RPTS. SO THE FIRST POINT THAT THE PLT RPTED WAS TEGOD. AT X34Z, TOKYO CTR CALLED TO VERIFY THE ASSIGNED ALT OF ACR X AS FL350 AND INDICATED THAT THE ACFT WAS AT FL390. I THEN CALLED GUAM CERAP TO VERIFY THE ASSIGNED ALT. THE CTLR SAID THAT THE ACFT WAS ASSIGNED TO CROSS 20 DEG N LATITUDE AT FL390. AT THIS TIME, I CALLED TOKYO AND ADVISED THEM THAT THE ACR X WAS IN FACT ASSIGNED FL390. AT THE TIME OF THE INCIDENT, SECTOR OC5 AT OAK ARTCC WAS EXTREMELY BUSY WITH HVY TFC (25 OR MORE ACFT) AND A VERY HIGH COMPLEXITY LEVEL. THE CORRECTIVE ACTION WOULD HAVE BEEN TO HAVE THE FIRST CTLR INDICATE THE PROPER ALT ON THE FLT PROGRESS STRIP.

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.