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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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Commercial radio controller transmits ZOA controller message to oceanic air carrier flight, unable climb clearance request, request for higher on file. Air carrier pilot reports climbing to requested altitude, and commercial radio controller does not catch error. When air carrier reports level, the xferred message is caught by ZOA. Long separation is lost. ZOA controller initiates control actions to regain required long separation.
| Attributes | |
| ACN | 407057 |
| Time | |
| Date | 199806 |
| Day | Tue |
| Local Time Of Day | 0001 To 0600 |
| Place | |
| Locale Reference | atc facility : nuo |
| State Reference | AK |
| Altitude | msl bound lower : 35000 msl bound upper : 35000 |
| Aircraft 1 | |
| Controlling Facilities | artcc : zoa tower : phl |
| Operator | common carrier : air carrier |
| Make Model Name | DC-10 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | climbout : intermediate altitude |
| Route In Use | enroute : other oceanic enroute : pacific |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | B747 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other |
| Flight Phase | cruise other |
| Route In Use | enroute : pacific enroute : other oceanic |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | other personnel other |
| Qualification | other other : other |
| ASRS Report | 407057 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | conflict : airborne less severe non adherence : published procedure non adherence : required legal separation other anomaly other |
| Independent Detector | other controllera |
| Resolutory Action | controller : issued new clearance other |
| Consequence | Other |
| Miss Distance | horizontal : 99999 vertical : 0 |
| Supplementary | |
| Air Traffic Incident | Operational Error |
Narrative:
At XA47Z aircraft #1 reported over position 3907N 165E at FL280 estimating position 38N 170E XB14Z and requested higher altitude up to FL370. At XA52Z ZOA issued a clearance: 'atcc aircraft #1 climb to and maintain FL290, report reaching. Unable requested altitude. Request on file.' the radio operator delivered the clearance correctly. Aircraft #1 read back an incorrect altitude of FL350 and the radio operator did not catch the incorrect readback. At XB02Z aircraft #1 reported level at FL350. ZOA then issued a clearance for the flight to maintain FL350. It was later determined that this flight had lost separation with another flight and this was classified as an FAA error. This was a readback/hearback error. Also involved was the expectancy factor.
Original NASA ASRS Text
Title: COMMERCIAL RADIO CTLR XMITS ZOA CTLR MESSAGE TO OCEANIC ACR FLT, UNABLE CLB CLRNC REQUEST, REQUEST FOR HIGHER ON FILE. ACR PLT RPTS CLBING TO REQUESTED ALT, AND COMMERCIAL RADIO CTLR DOES NOT CATCH ERROR. WHEN ACR RPTS LEVEL, THE XFERRED MESSAGE IS CAUGHT BY ZOA. LONG SEPARATION IS LOST. ZOA CTLR INITIATES CTL ACTIONS TO REGAIN REQUIRED LONG SEPARATION.
Narrative: AT XA47Z ACFT #1 RPTED OVER POS 3907N 165E AT FL280 ESTIMATING POS 38N 170E XB14Z AND REQUESTED HIGHER ALT UP TO FL370. AT XA52Z ZOA ISSUED A CLRNC: 'ATCC ACFT #1 CLB TO AND MAINTAIN FL290, RPT REACHING. UNABLE REQUESTED ALT. REQUEST ON FILE.' THE RADIO OPERATOR DELIVERED THE CLRNC CORRECTLY. ACFT #1 READ BACK AN INCORRECT ALT OF FL350 AND THE RADIO OPERATOR DID NOT CATCH THE INCORRECT READBACK. AT XB02Z ACFT #1 RPTED LEVEL AT FL350. ZOA THEN ISSUED A CLRNC FOR THE FLT TO MAINTAIN FL350. IT WAS LATER DETERMINED THAT THIS FLT HAD LOST SEPARATION WITH ANOTHER FLT AND THIS WAS CLASSIFIED AS AN FAA ERROR. THIS WAS A READBACK/HEARBACK ERROR. ALSO INVOLVED WAS THE EXPECTANCY FACTOR.
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.