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Aircraft changes altimeter setting to a qnh setting when above the transition altitude, causing the aircraft to climb 600 ft above assigned cruise altitude.
| Attributes | |
| ACN | 299325 |
| Time | |
| Date | 199503 |
| Day | Thu |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | atc facility : bnn airport : lhr |
| State Reference | FO |
| Altitude | msl bound lower : 8000 msl bound upper : 8600 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : lhr |
| Operator | general aviation : corporate |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | Other Other |
| Flight Phase | descent other |
| Route In Use | enroute : on vectors |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 50 flight time total : 12000 flight time type : 500 |
| ASRS Report | 299325 |
| Person 2 | |
| Affiliation | Other |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude non adherence : clearance |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : returned to intended course or assigned course |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
Event was due to ATC procedures differences in foreign countries. In level flight at 8000 ft we received a qnh altimeter setting. As this altimeter setting would result in a large change from the qne altitude we were assigned, the copilot questioned the setting several times. After these confirmations, the copilot felt that the setting was to be implemented and he instructed the captain to change his altimeter. The change caused the aircraft to climb 600 ft above the assigned flight level. Aircraft was never released from autoplt/autothrottle. We should have asked, do you want us on qne or qnh at this time? In the USA we receive qnh when needed (ie, cleared to 14000 ft altimeter 29.98). In the united kingdom, ATC often gives a qnh setting in advance to be used for a future descent.
Original NASA ASRS Text
Title: ACFT CHANGES ALTIMETER SETTING TO A QNH SETTING WHEN ABOVE THE TRANSITION ALT, CAUSING THE ACFT TO CLB 600 FT ABOVE ASSIGNED CRUISE ALT.
Narrative: EVENT WAS DUE TO ATC PROCS DIFFERENCES IN FOREIGN COUNTRIES. IN LEVEL FLT AT 8000 FT WE RECEIVED A QNH ALTIMETER SETTING. AS THIS ALTIMETER SETTING WOULD RESULT IN A LARGE CHANGE FROM THE QNE ALT WE WERE ASSIGNED, THE COPLT QUESTIONED THE SETTING SEVERAL TIMES. AFTER THESE CONFIRMATIONS, THE COPLT FELT THAT THE SETTING WAS TO BE IMPLEMENTED AND HE INSTRUCTED THE CAPT TO CHANGE HIS ALTIMETER. THE CHANGE CAUSED THE ACFT TO CLB 600 FT ABOVE THE ASSIGNED FLT LEVEL. ACFT WAS NEVER RELEASED FROM AUTOPLT/AUTOTHROTTLE. WE SHOULD HAVE ASKED, DO YOU WANT US ON QNE OR QNH AT THIS TIME? IN THE USA WE RECEIVE QNH WHEN NEEDED (IE, CLRED TO 14000 FT ALTIMETER 29.98). IN THE UNITED KINGDOM, ATC OFTEN GIVES A QNH SETTING IN ADVANCE TO BE USED FOR A FUTURE DSCNT.
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.