Use of strategic lateral offset procedures on crowded routes across the North Atlantic has increased significantly in the past two years, according to data compiled by air navigation service providers that handle air traffic in the area.
For aircraft that reported their positions via automatic dependent surveillance–contract (ADS–C)1, data showed that from October through December 2009, about 40 percent were using offset procedures, which allow pilots to fly parallel to an airway centerline and either 1 nm or 2 nm to its right. The procedures are available to pilots of aircraft in “oceanic and remote” airspace between Flight Level (FL) 290 (approximately 29,000 ft) and FL 410 — the airspace in which reduced vertical separation minimum (RVSM) procedures have cut the standard vertical separation of aircraft from 2,000 ft to 1,000 ft.
The 40 percent figure for use of offset procedures compares to 10 percent in 2007 and t…
