Guidance concerning Air Navigation in and above the NAT MNPSA
CHAPTER 14: GUARDING AGAINST COMPLACENCY
Since 1977, when the MNPS rules were introduced, careful monitoring procedures have
provided a good indication both of the frequency with which navigation errors occur and their causes. Their frequency is low: only one flight in around ten thousand commits a serious navigation error. However because of the accuracy and reliability of modern navigation systems, the errors which do occur are most often seen to be as a result of aircrew error.
Operational errors in the vertical plane also occur. Aircraft are sometimes flown at levels
other than those for which ATC clearance has been issued. In preparation for the introduction of RVSM in the NAT Region (1997) a comprehensive data collection programme for vertical deviations was implemented, together with an annual assessment of the resulting collision risks. As in the horizontal plane, the frequency of vertical errors is low. However, the potential risk of even a single incidence of flying at an uncleared level can be very significant. Currently, the NAT MNPSA risk estimates in the vertical plane, as a result of operational errors or uncleared departures from flight level, exceed those arising from lateral gross
It is therefore essential that crews do not take modern technology for granted. They should
at all times, especially during periods of low workload, guard against complacency and over-confidence, by adhering rigidly to approved cockpit/flight deck procedures which have been formulated over many years, in order to help stop operational errors from being an inevitability.
This chapter lists some of the errors that have been recorded in the NAT during recent years.
Also the NATSPG commissioned the UK National Air Traffic Services to produce an interactive DVD ROM, “On the Right Track”, which highlights many of the common errors and discusses their causes. The DVD ROM additionally contains general information on Air Traffic Control in the North Atlantic Region. The DVD ROM, like this Manual, is aimed at pilots, dispatchers and others concerned in operations on the
North Atlantic. It is firstname.lastname@example.org.
available at no charge to Furthermore, an Oceanic Errors
fide operators on Bulletin is available
application to: for downloading
currently augmented by a NAT Safety Alert. It is suggested that pilots consult these sources regularly.
OPERATIONAL HEIGHT ERRORS
The most common height errors are caused by:
executing an uncleared climb.
g. the crew of an aircraft entering Reykjavik OCA from Edmonton FIR encountered HF
Blackout conditions prior to reaching the Reykjavik OCA boundary and before receiving an Oceanic Clearance. During the subsequent more than two hours of flight in the MNPSA, the crew executed two step climbs before re-establishing contact with ATC.
Aircraft following an ATC clearance are assured of separation from other potentially conflicting
traffic. In HF Blackout conditions if an aircraft unilaterally changes level, ATC has advise or intervene with other traffic and separation can no longer be assured. circumstance, if a climb without ATC clearance is imperative then this should be contingency and the appropriate track offset of 15 NM should be flown.
NAT Doc 007