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Guidance concerning Air Navigation in and above the NAT MNPSA



All navigational information appearing on the Master Document must be checked against the

best available prime source data. When a re-route is necessary, some regulators recommended that a new Master Document is prepared for the changed portion of the flight. In cases where the original Master Document is to be used, the old waypoints must be clearly crossed out and the new ones carefully entered in their place. The checks listed in the previous paragraph must be carried out in respect of all new or revised



When ATC clearances or re-clearances are being obtained, headsets should be worn. The

inferior clarity of loud-speakers has, in the past, caused errors during receipt. Two qualified crew members should monitor such clearances; one of them recording the clearance on the Master Document as it is received, the other cross-checking the receipt and read-back. All waypoint co-ordinates should be read back in detail, adhering strictly to standard ICAO phraseology, except where approved local procedures make this unnecessary. Detailed procedures pertaining to abbreviated clearances/read-backs are contained in the appropriate AIPs, and in this Manual at Chapter 5 - Oceanic ATC Clearances.

Position Plotting


A simple plotting chart provides a visual presentation of the intended route which, is defined

otherwise only in terms of navigational co-ordinates. Plotting the intended route on such a chart may reveal errors and discrepancies in the navigational co-ordinates which can then be corrected immediately, before they reveal themselves in terms of a deviation from the ATC cleared route. As the flight progresses, plotting the aircraft's present position on this chart will also serve the purpose of a navigation cross check, provided that the scale and graticule are suitable.


As the flight progresses in oceanic airspace, plotting the aircraft's position on this chart will

help to confirm (when it falls precisely on track) that the flight is proceeding in accordance with its clearance. However, if the plotted position is laterally offset, the flight may be deviating unintentionally, and this possibility should be investigated at once.


It is recommended that a chart with an appropriate scale be used for plotting. Many company

Progress Charts are of the wrong scale or too small. It has been noted that the use of plotting charts that are small can lead to oceanic errors. EAG Chart AT (H) 1; No 1 AIDU (MOD) Charts AT(H)1, 2, 3 & 4 and the Jeppesen North/Mid Atlantic Plotting Charts are all useful compromises between scale and overall chart size; while the NOAA/FAA North Atlantic Route Chart has the advantage, for plotting purposes, of a 1°

latitude/longitude graticule.

Provision of Step-Climbs


Tactical ATS Surveillance control and tactical procedural control are exercised in some areas

of the NAT MNPS Airspace. However, oceanic clearances for most NAT flights are of a strategic nature, whereby flights are allocated a conflict-free route and profile from coast-out to landfall. Although such strategic clearances normally specify a single flight level for the entire crossing, there is often scope for en route step-climb re-clearances as fuel burn-off makes higher levels more optimal. Controllers will accommodate requests for step-climbs whenever possible. When so re-cleared, pilots should initiate the climb without delay (unless their discretion was invited or unless a conditional clearance was issued) and

always report to ATC immediately upon leaving the old and on reaching the new cruising levels.

Relief Crew Members


Very long range operations may include the use of relief crew. In such cases it is necessary

to ensure that procedures are such that the continuity of the operation is not interrupted, particularly in

respect of the handling and treatment of the navigational information.

NAT Doc 007


Edition 2010

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