Like most other North Atlantic (NAT) traffic flows, traffic on the Europe-Alaska axis is predominantly unidirectional; in the Reykjavik control area (CTA) the westbound peak is between 1200 - 1800 coordinated universal time (UTC), and the eastbound peak is between 0001 - 0600 UTC. To facilitate the flow of this traffic during the peak period and to avoid a multiplicity of random routes, a polar track structure (PTS) consisting of 10 fixed tracks has been established (see Appendix 2). Although not mandatory, flights planning to operate on the Europe-Alaska axis at flight level (FL) 310 - 390 inclusive during peak periods are strongly recommended to submit flight plans in accordance with one of the promulgated PTS tracks.

Even though equipment has improved greatly since Admiral Byrd's day, the inherent hazardous conditions still exist. Admiral Byrd in his book, "First to the North Pole," which has been excerpted in "Men in the Air," Crown Publishers, Inc., New York. Copyright 1990 by Brandt Aymar, significantly detailed the extreme hazards of operating in this hostile environments. These are some of the points that he made:

1 . The utmost attention to detail to flight planning.

2. The importance of survival equipment, including food supplies if a long trek over the ice cap became an eventuality.

3. A means for obtaining food supplies from nature, for example rifle, an ice axe and fishing gear.

4. The lack of reliability of the magnetic compass, which in polar regions can point more than a thousand miles south of the North Geographic Pole.

5. The lack of accuracy of the gyroscopic compass, which when nearing the Pole, would have a tendency to point straight up in the air.

6. The severity of wind conditions and its effect on navigation.

It is evident from the above that flight in the far north is difficult. These trips require detailed planning, an abundance of equipment, extensive knowledge, and some luck in not experiencing any undue circumstances such as un-forecast weather, navigation and/or communication failure, engine problems, or airframe problems. Byrd's thoughts are included in this advisory circular (AC) as "food for thought." In spite of the advances in aircraft and navigation/communication equipment, the harsh realities of flight in the far north are ever present. Loss or failure of any equipment reduces the flight to one that relies on the basic and emergency equipment that is carried and the extent of knowledge which the crew has in its use.

The rapidly changing world of Global Positioning System (GPS) navigation is making this an attractive system for use in making trans polar flights. However, caution should be exercised when using GPS. On Thursday, February 3, 1994, Transport Canada made a presentation as a part of an FAA GPS Seminar and stated that GPS is being advocated in Canada as much as it is in the United States because of its potential use as an economic navigation system in many of the remote areas served by Canadian operations. They further stated that although GPS can make a significant economical impact on operations in Canada, that their research in the vicinity of Resolute Bay (N74°44.8' W94°59.7') indicates a lack of integrity with stand alone GPS navigation systems. It is therefore recommended that operators intending to utilize GPS as a principal source of navigation in the polar regions, contact transport Canada regarding the latest status of their integrity studies.