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Mach speed change requested for oceanic flight was not received by the crew but was assumed issued by the controling agency.
| Attributes | |
| ACN | 479380 |
| Time | |
| Date | 200007 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : zoa.artcc |
| State Reference | CA |
| Altitude | msl single value : 34000 |
| Environment | |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zoa.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B757 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | cruise : level |
| Route In Use | enroute : pacific |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| ASRS Report | 479380 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : multi engine pilot : instrument |
| Events | |
| Anomaly | non adherence : clearance other anomaly other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | none taken : detected after the fact |
| Consequence | other |
| Supplementary | |
| Problem Areas | ATC Human Performance Flight Crew Human Performance ATC Facility |
| Primary Problem | Flight Crew Human Performance |
Narrative:
Prior to departure, captain directed first officer to request new cruise speed from clearance delivery due to expected late arrival in ogg. First officer made request. During climb out captain queried if we had been given new speed. First officer said he would request it from sfo oceanic. Miscom due to cockpit workload during departure resulted in a higher cruise mach than actually cleared for. Subsequently ATC requested cruise speed and we advised them mach .81. They then reclred us to mach .82 and we ascertained that it was due to traffic gaining on us from behind. Will re-emphasize need for both pilots acknowledge receipt of clearance.
Original NASA ASRS Text
Title: MACH SPD CHANGE REQUESTED FOR OCEANIC FLT WAS NOT RECEIVED BY THE CREW BUT WAS ASSUMED ISSUED BY THE CTLING AGENCY.
Narrative: PRIOR TO DEP, CAPT DIRECTED FO TO REQUEST NEW CRUISE SPD FROM CLRNC DELIVERY DUE TO EXPECTED LATE ARR IN OGG. FO MADE REQUEST. DURING CLBOUT CAPT QUERIED IF WE HAD BEEN GIVEN NEW SPD. FO SAID HE WOULD REQUEST IT FROM SFO OCEANIC. MISCOM DUE TO COCKPIT WORKLOAD DURING DEP RESULTED IN A HIGHER CRUISE MACH THAN ACTUALLY CLRED FOR. SUBSEQUENTLY ATC REQUESTED CRUISE SPD AND WE ADVISED THEM MACH .81. THEY THEN RECLRED US TO MACH .82 AND WE ASCERTAINED THAT IT WAS DUE TO TFC GAINING ON US FROM BEHIND. WILL RE-EMPHASIZE NEED FOR BOTH PLTS ACKNOWLEDGE RECEIPT OF CLRNC.
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.