IBAC Bulletin B 02-7

Subject: NAT – Genav GNEs remain disproportionately and disappointingly high in 2001 !

The annual report to the ICAO North Atlantic Systems Planning Group (NAT SPG) for Gross Navigation Errors (GNEs) for calendar year 2001 revealed, using flights per GNE, that overall performance was notably better than for year 2000 but significantly worse for International General Aviation (IGA) and military aircraft.

OACs played a significant part in containing the number of GNEs through the timely intervention to prevent incorrect routing. There were 79 occasions when such action was taken. Crew “blunder” error or probable crew error accounted for 64 of these interventions and thus remains the biggest factor in ATC having to intervene to prevent a GNE.

In discussing methods of improving the observed standard of navigation performance, the SPG noted that a very high number of GNEs had been caused by pilot error following a reroute. Also a number involved ‘glass cockpit’ aircraft (Ed note: unsurprisingly).

The SPG considered that some GNEs could have been prevented had the crew transmitted the position reports directly form the FMS progress or report pages and not from the paper flight log or AIREP reporting form. By transmitting the position report directly from the FMS progress report page, any transcription error would most likely be noticed by ATC thus prompting an ATC intervention to prevent a GNE. Furthermore, had the crew involved used track and distance tables, they may have realised that they had entered incorrect data into the FMS.

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Prepared by:

Peter R. Ingleton
IBAC Director, ICAO Liaison
19 November 2002