A Complete Manual for Conducting International Flight Operations
Approaching Oceanic Exit
Approaching Oceanic Exit
When approaching oceanic exit, the best practice is as follows:
Obtain domestic clearance (if necessary)- Flight crewmembers need to understand the clearance limit. Generally a clearance will clear an aircraft to depart from domestic airspace to the oceanic entry point, where an oceanic clearance must be obtained which terminates at the oceanic exit point. At the oceanic exit point the original clearance will be reapplied. If, however, there was an oceanic reroute, or if the clearance limit did not include the domestic airspace at the oceanic exit point, it will be necessary for the crew to obtain an amended clearance. A significant number of pilot/controller deviations have occurred due to aircraft transitioning oceanic/domestic airspace at levels or on routes for which they have not been cleared.
Establish Oceanic Exit Speed, Altitude and Reconfirm FMS Compliance with Clearance
Generally the routing when exiting oceanic airspace will be as cleared in the initial clearance which was received on the ground at the point of departure, or as received in the initial oceanic clearance. There have been, however, instances where oceanic changes in flight levels and speeds were not communicated to the local controlling agency at coast-in causing loss of separation vertically or horizontally.
With respect to speed, while the aircraft is in oceanic airspace speeds are expressed and maintained in mach, where as the transition to domestic airspace will be expressed in True Airspeed. In examining the filed ICAO flight plan you may notice at the exit point a change in airspeed such as (FOGGY/N440/F370) If there is a significant discrepancy between the oceanic cruise mach and the coast-in true airspeed, the controlling agency shall be contacted.
In this example at the coast-in point, SUM, the filed speed is 500 knots true at FL410 which will be transitioned to from the filed speed of mach .87. It is also possible that due to an oceanic reroute that the exit fix no longer corresponds with the domestic routing. It is the flight crew’s responsibility to catch this error and request an amended clearance if necessary.
Lateral Offset Procedures are a useful technique for avoiding aircraft in the congested airspace of the North Atlantic or the Pacific. A couple key points, SLOP is always right of course by either 1NM or 2 NM, although in some airspace where separation is less than 30 NM laterally SLOP increments of in .1 NM up to .5 NM may be permitted. Flight crew members shall reference ICAO PANS-ATM Doc 4444 and NAT Doc 007 for flights in the North Atlantic.
You generally do not need to request permission to perform SLOP procedures, however, it does put the onerous on the flight crew to remember to remove SLOP prior to the oceanic exit. It is recommended that removing SLOP becomes a checklist item when approaching the oceanic exit. A few more points of emphasis is to be aware of what areas of the world or airspace permit the use of SLOP, because not all of them do. It is also worth mentioning that the use of SLOP may affect the direction of turn should a contingency
such as a depressurization, medical emergency or loss of an engine occur. It is worth briefing initial contingency actions when initiating SLOP.
In the event of a weather deviation while utilizing SLOP, the weather deviation is granted on the distance from the centerline of the airway, and the flight crew shall remove the lateral offset to stay within the granted deviation.
Revision date: July 29, 2015
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