Guidance concerning Air Navigation in and above the NAT MNPSA
time periods and outside them. At specified times, some appropriate direction levels are in fact reserved for use by the opposite direction traffic flows that then predominate. The current usage allocation of flight levels in the NAT MNPSA is published in the UK and Canadian AIPs and shown at Attachment 6 as the NAT Flight Level Allocation Scheme (FLAS). Hence, pilots and planners should always consult the current AIPs and any supporting NOTAMs when flight planning random routes through NAT MNPS Airspace. If a flight is expected to be level critical, operators should contact the initial OAC prior to filing of the flight plan to determine the likely availability of specific flight levels.
In NAT MNPS Airspace the Mach Number technique is used to manage longitudinal
separations between aircraft following the same track. Chapter 7 above provides more detailed information. Consequently, flight plans for the NAT MNPS segment of flight must define aircraft speed in terms of a Mach Number. This is true even if procedures dictate that aircraft speed be defined in terms of TAS for other (continental airspace) segments of that same flight. Oceanic clearances include a True Mach Number to follow and because this is used by ATC to regulate longitudinal separations, no tolerance is permissible. Consequently, NAT flights should not be planned or flown on the assumption that LRC or ECON fuel
regimes may be used.
ATC FPL Completion
It is important that all of the foregoing conventions and protocols are adhered to when
planning a flight through NAT MNPS Airspace. Summarised guidance on the flight planning requirements for specific routes is given above at Paragraph 4.2. Correct completion and addressing of the filed ATC flight plan is extremely important. Non-observance of any of the foregoing NAT MNPS Airspace planning principles, or even simple syntax errors in the filed FPL, can lead to delays in data processing and/or to the subsequent issuing of clearances to the flights concerned. Despite the growing use of automated flight planning systems a significant proportion of ATC Flight Plans submitted in respect of flights through the North Atlantic Region continue to contain errors. In some instances these errors are such that the Flight Plan is rejected and the Operator is required to re-submit a corrected version. Full and detailed explanations of how to complete an ATS Flight Plan in respect of the NAT portion of a flight are shown at Attachment 4. This document highlights the more common completion errors that are made and includes example, correctly-completed-ICAO Flight Plans. New and/or infrequent North Atlantic operators are earnestly recommended to make diligent reference to this document. Furthermore it should be noted that a free text editor is available on the Eurocontol website that can validate any proposed ICAO flight plan before filing. It will advise if a flight plan is acceptable for routes, altitudes and transitions. If the flight plan would be rejected, this editor will describe what is wrong, thereby allowing the operator to repair it before filing.
If filing via an OTS track, particularly during peak traffic periods, it must be appreciated that
ATC may not be able to clear the aircraft as planned. ATC will, if possible, first offer a clearance on the planned track but at a different Flight Level. If, however, no reasonable alternative level is available, or if the offered Flight Level is unacceptable to the pilot, then ATC will clear the aircraft via another OTS track. When filing the ATC Flight Plan, the Dispatcher may enter the details of such an acceptable alternative track in Field 18 of the ICAO FPL. This will be taken into account by ATC if indeed having to clear the aircraft
via a route other than that planned.
In order to signify that a flight is approved to operate in NAT MNPS Airspace, the letter ‘X’
shall be inserted, in addition to the letter ‘S’, within Item 10 of the flight plan. A ‘W’ must also be included
in Item 10 to indicate that the flight is approved for RVSM operations.
For flights which also intend to operate through the WATRS Plus Airspace RNP-10 or RNP-
4 approval is required in order to benefit from 50NM lateral separation employed here. Any MNPSA aircraft
NAT Doc 007