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All four B747 pilots failed to recognize the foreign airport's 997 hector pascal altimeter and allowed 29.97 qnh to remain in the altimeter; despite ATC's repeated correction; which made the aircraft about 500 ft low on approach.
| Attributes | |
| ACN | 1098463 |
| Time | |
| Date | 201306 |
| Local Time Of Day | 0001-0600 |
| Place | |
| Locale Reference | ZZZZ.Airport |
| State Reference | FO |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Make Model Name | B747 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Final Approach Initial Approach Landing |
| Flight Plan | IFR |
| Component | |
| Aircraft Component | Altimeter |
| Person 1 | |
| Function | First Officer Pilot Flying |
| Person 2 | |
| Function | Captain |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Last 90 Days 200 Flight Crew Total 27500 Flight Crew Type 4500 |
| Events | |
| Anomaly | ATC Issue All Types Deviation - Altitude Excursion From Assigned Altitude Deviation - Altitude Undershoot Deviation - Procedural Published Material / Policy |
Narrative:
Military charter. On approach forgot to say hector pascals or hpa or qnh. Approach controller issued 2997...and repeated back as 2997 when asked again. (997 hpa equals 2947 qnh and can be as much as 500 ft off of 299 7QNH). After verification; controller said aircraft transponder reading low. Again confirmed altitude with controller and 2;000 ft; cleared for visual. Conditions were night VMC vertical visibility excellent; forward visibility 20 plus. Visual approach backed up with ILS; VASI's working. Noticed glideslope intercept off altitude for distance. Confirmed with controller and then he said 997 without any units of measurement. Normal landing; segment completed with no other events.
Original NASA ASRS Text
Title: All four B747 pilots failed to recognize the foreign airport's 997 Hector Pascal altimeter and allowed 29.97 QNH to remain in the altimeter; despite ATC's repeated correction; which made the aircraft about 500 FT low on approach.
Narrative: Military Charter. On approach forgot to say Hector Pascals or HPA or QNH. Approach Controller issued 2997...and repeated back as 2997 when asked again. (997 HPA equals 2947 QNH and can be as much as 500 FT off of 299 7QNH). After verification; Controller said aircraft transponder reading low. Again confirmed altitude with Controller and 2;000 FT; cleared for Visual. Conditions were night VMC vertical visibility excellent; forward visibility 20 plus. Visual approach backed up with ILS; VASI's working. Noticed glideslope intercept off altitude for distance. Confirmed with Controller and then he said 997 without any units of measurement. Normal landing; segment completed with no other events.
Data retrieved from NASA's ASRS site as of July 2013 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.