Guidance concerning Air Navigation in and above the NAT MNPSA
the State concerned, using the speediest means available (facsimile, AFTN, etc.) and with the least possible delay. This should be followed as soon as possible by a written confirmation.. All notifications should be copied to the CMA; and
the appropriate State of Registry or the State of the Operator will be sent a copy of the written confirmation along with a covering letter by the CMA.
For aircraft operating outside MNPS Airspace:
the observing ATC unit should, if at all possible, inform the pilot of the aircraft concerned of the observed error and also that an error report may be processed; any comment made by the pilot at the time of notification should be recorded;
where the observed deviation from track is 50 NM or more, the procedure detailed in the previous paragraph (covering aircraft operating within MNPS Airspace) will be followed (see Appendix C); and
where the observed deviation from track is 25 NM or more but less than 50 NM, the observing ATC unit, or other agency designated by the State, should notify the CMA of the deviation with the least possible delay (facsimile, AFTN etc.) using the appropriate message format shown at Appendix C. This should be followed as soon as possible by a written confirmation where this is deemed necessary. The CMA will then advise the State of operator or State of Registry.
Further Follow-up Action by the Operator and/or State of Registry
Subsequent follow-up action on observed deviations of 25 NM or more, notified in
accordance with the above provisions, should initially be conducted between the Operator and a designated agency of the State having responsibility for the ATC unit which observed the deviation, on the understanding that:
the errors outlined in sub-paragraph c) above (i.e. deviations 25 NM or more but less than 50 NM occurring outside MNPS Airspace) will not normally require further action;
the State of Registry or the State of the Operator concerned should be requested to conduct a further investigation if deemed necessary;
all correspondence should be copied to the CMA; and
the EUR/NAT Office of ICAO will assist in those cases where no response is obtained from
either the Operator concerned or the State of Registry.
Follow-up Action on Observed and Reported Altitude Deviations
Height monitoring by the NAT CMA includes the monitoring of technical height-keeping
accuracy and operational errors in the vertical plane.
For monitoring technical height-keeping accuracy, a hybrid system comprising a Height
Monitoring Unit (HMU) and GPS Monitoring Systems (GMSs) is employed. The HMU is located near Strumble (in the United Kingdom). The GMS consists of portable GMUs, GPS reference stations, access to Mode C and MET information, post-flight processing facilities and logistic support. All data collected by
the system is analysed and collated by the CMA.
NAT Doc 007