Guidance concerning Air Navigation in and above the NAT MNPSA
is seldom a problem as long as at least 1 degree of separation is subsequently maintained from other tracks.
Random routes paralleling the OTS 1 or 2 degrees north or south can be as busy as the OTS
Dispatchers planning NAT flights originating in south Florida or the Caribbean should
consider the effect of traffic from South America operating north eastwards to the USA, when deciding on flight levels. Although the dispatcher should plan optimum flight levels, adequate fuel should be carried so
that a NAT flight can accept a lower altitude (FL260 or FL280) until east of 70 ˚W.
Any flight planning to leave an OTS track after the oceanic entry point must be treated as a
random route. The track letter must not be used to abbreviate the route description.
Flights operated against the peak traffic flows should plan to avoid the opposite direction
OTS. Even if operating outside of the validity periods of the OTS some restrictions on routings may apply. These can affect Eastbound traffic crossing 30W at 1030 UTC or later; and Westbound traffic crossing 30W at 2400 UTC and later (See Chapter 4, paragraph 4.1.6). If in any doubt it would be prudent to co-ordinate
any such routes directly with appropriate OACs.
Flight Dispatchers should be aware of the North Atlantic Flight Level Allocation Scheme
(FLAS). This is subject to change and the current FLAS is published in the UK and Canadian AIPs and
shown at Attachment 6.
Chapters 2 and 4 contain details on RVSM flight level guidance. Since virtually all airspace
adjoining MNPS airspace is now RVSM, transition problems are no longer a major issue for ATC or dispatchers. Nevertheless dispatchers should be aware that some “opposite direction” levels, which may be flight planned for the NAT segment of a flight, may not be similarly allowed in adjacent domestic areas.
Guidance for RVSM flight procedures in MNPS airspace can be found in Chapter 9 of this Manual.
RVSM allows more flight levels for planning and therefore provides better opportunity to fly
closer to an optimum route/profile. As aircraft fly towards their destination they become lighter as fuel on- board is consumed and they are then able to climb to more fuel efficient altitudes. It is acceptable to plan and/or request step climbs within the OTS but because of traffic volumes and the difference in aircraft performance it is wise to plan conservatively. Climbs on random routes that are totally north or south of the track system are more readily approved. If a flight is planned without profiling a climb crews should be
encouraged to request a climb as aircraft decreasing weight permits.
The availability of functioning HF ATS communications is mandatory for flights through the
Shanwick OCA. Many States of Registry insist on two functioning long range communications systems for
flights in Oceanic or Remote areas. SATCOM Voice for one HF system. Registry requirements in this regard.
Some States of Registry will allow their Dispatchers should ensure that they are fully VHF communications (freq 123.45 or 121.5)
operators to substitute aware of their State of can be used as to relay
air-ground ATS communications as backup in case of en route HF failure.
Many operators now use ADS-C (automatic dependent surveillance) and CPDLC (controller
pilot data link communications) for oceanic position reporting and clearance updating.
improve position reporting speed and accuracy.
They also reduce the chance of errors.
registration with the ATS Providers may be required if ADS/CPDLC are to be used in the NAT Region.
NAT Doc 007