Guidance concerning Air Navigation in and above the NAT MNPSA
preparing a new plotting chart.
When reviewing the causes of navigation errors the NAT CMA has noted that numerous
operator reports make reference to crew breaks in their explanation of the circumstances of the error. In all dimensions, errors are more likely to occur where a clearance or re-route, speed or level change has been communicated to a crew and either not been actioned completely, or has been incorrectly or incompletely processed before a relief crew member has started duty. Operators’ SOPs are generally consistent in regard to the importance of properly handing over, and taking control, and if adopted with due diligence, would forestall the development of an error. However, human factors often confound the best laid SOPs, and distraction or human failings can contribute to the omission of all, or a part of, the process handed over by the departed crew member for subsequent action. Flights requiring crew augmentation, particularly, ultra- long-haul flights present specific issues as regards to crew relief. With the requirement to have the aircraft commander and the designated co-pilot on duty for critical stages of the flight i.e.: take off and landing, sometimes crew changes then occur during times when critical information is being received such as oceanic
clearances or conditional clearances and/or company communications imperative that during these crew changes, a thorough turnover briefing crew is aware of all clearances and requirements for the segment of the
as re-dispatch etc.
conditional re-clearances such as a change of level at specific points or times.
Strict adherence to all the above procedures should minimise the risk of error. However,
flight deck management should be such that one pilot is designated to be responsible for flying the aircraft whilst the other pilot carries out any required amendments to documentation and reprogramming of the navigation systems - appropriately monitored by the pilot flying the aircraft, as and when necessary.
Approaching the Ocean
Prior to entering MNPS Airspace, the accuracy of the LRNSs should be thoroughly checked,
if necessary by using independent navigation aids. For example, INS position can be checked by reference to en route or proximate VOR/DMEs, etc. However, with a modern FMS, the system decides which LRNS is to be used, and indeed, the FMS may be taking information from DMEs (and possibly VORs) as well as the LRNS carried. Nevertheless, in spite of all this modern technology and even if the FMS is using GPS, it is still worthwhile to carry out a 'reasonableness' check of the FMS/GPS position, using (for example) DME/VOR distance and bearing.
When appropriate and possible, the navigation system which, in the opinion of the pilot, has
performed most accurately since departure should be selected for automatic navigation steering.
In view of the importance of following the correct track in oceanic airspace, it is advisable at
this stage of flight that, if carried, a third pilot or equivalent crew member should check the clearance waypoints which have been inserted into the navigation system, using source information such as the track message or data link clearance if applicable.
Entering the MNPS Airspace and Reaching an Oceanic Waypoint
When passing waypoints, the following checks should be carried out:
just prior to the waypoint, check the present position co-ordinates of each navigation system against the cleared route in the Master Document, and
check the next two waypoints in each navigation system against the Master Document.
at the waypoint, check the distance to the next waypoint, confirm that the aircraft turns in the correct direction and takes up a new heading and track appropriate to the leg to the next waypoint.
NAT Doc 007