AN ACR CREW MISSED THE CHINESE RVSM FEET TO METERS ALTITUDE CONVERSION AND LEVELED OFF 100 FT IN ERROR.
Synopsis
AN ACR CREW MISSED THE CHINESE RVSM FEET TO METERS ALTITUDE CONVERSION AND LEVELED OFF 100 FT IN ERROR.
Narrative
AFTER LEVELING AT 8100 METERS ON INITIAL CLBOUT OF ZZZ; WE WERE GIVEN ANOTHER CLB TO 8900 METERS. FO CHKED THE ALTIMETER METRIC CONVERSION TABLE AND WE BOTH CONFIRMED 29200 WAS THE CORRECT ALT IN FT TO SET IN THE WINDOW. ONCE 29.2 WAS SET IN THE ALT WINDOW; 8900 METERS WAS CONFIRMED ON THE DIGITAL STANDBY ALTIMETER. WE CLBED AND LEVELED OFF AT 29.2. SINCE WE WERE FILED FOR 31.2 FINAL ALT WE THOUGHT THIS WAS ANOTHER INTERIM LEVELOFF PRIOR TO FINAL CRUISE ALT ASSIGNMENT. SHORTLY AFTER LEVELING AT 29.2 THE CTLR CALLED AND ASKED IF OUR ALT WAS '29.2 OR 29.1?' WE RESPONDED WE WERE LEVEL AT 29.2. HE STATED WE SHOULD BE AT 29.1. WE ROGERED AND SAID WE WERE DSNDING FROM 29.2 TO 29.1. AFTER LEVELING AT 29.1 THE DIGITAL STANDBY ALTIMETER SHOWED 8870 METERS. NO FURTHER DISCUSSION OCCURRED AND A FEW MINS LATER WE WERE XFERRED TO INCHEON CTL. AFTER THIS RADIO DISCUSSION WE CHKED THE CHINA RVSM FL ALLOCATION SCHEME CHART AND CONFIRMED THE ATC ASSIGNED RVSM LEVEL WHILE HDG E FOR 8900 METERS IS 29100 FT. THIS DEV OCCURRED FOR 2 REASONS. FIRST; WE DID NOT KNOW 8900 METERS WAS GOING TO BE OUR FINAL ALT. SECOND; WE DID NOT CHK THE RVSM SIDE OF THE CHART TO NOTE THE DISCREPANCY OF 8900 METERS BEING 29.2 ON ONE SIDE AND 29.1 ON THE RVSM SIDE. ADDITIONALLY IT IS WORTH NOTING THE CONVERSATION WITH THE CHINESE CTLR WAS ABOUT OUR ALT IN FT NOT METERS. THIS DEV CAN BE PREVENTED BY ATC INFORMING US OF FINAL ALT ASSIGNMENT OR CREW ASKING FOR CLARIFICATION. ALSO IT WOULD BE HELPFUL TO HIGHLIGHT ON THE ALTIMETER METRIC CONVERSION TABLE THOSE NUMEROUS (7) ALTS THAT ARE DIFFERENT BY 100 FT ON THE 2 SIDES OF THE CHART.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.