Aircraft requiring rapid/emergency descent or diversion within RVSM airspace (except China/ DPRK) should leave the assigned route by turning at least 45° right or left, and acquire a track offset, which is the mid-point from the adjacent parallel track for all regions except Middle East and Oceanic regions. The offset for the Middle East region is 25 NM, while the offset for Oceanic regions is 15 NM. The initial direction of the turn will be determined by the relative position of other aircraft, adjacent airways and terrain. When an aircraft is able to maintain its assigned level and has deviated by 10 NM from the original track centreline, then climb or descend to a level 500 FT different from the normally assigned by ATC. When an aircraft is unable to maintain its ATC assigned level, the rate of descent should be minimized whenever possible and the subsequently selected level flight should differ by 500 FT from those normally assigned by ATC. If an aircraft requires to divert across the flow of adjacent traffic, it should expedite climb above or descent below levels where the majority of aircraft operate (e.g. to a level above FL 410 or below FL 290) and then maintain a level which differs by 500 FT from those normally assigned by ATC. However, if the Commander/PIC is unable or unwilling to climb above FL 410 or descent below FL 290, the aircraft should be flown at a level 500 FT above or below levels normally assigned until a new ATC clearance is obtained. • China/DPRK RVSM. Aircraft requiring rapid/emergency descent or diversion within China/DPRK RVSM airspace should leave the assigned airway by turning 30° RIGHT and intercept a 5 NM offset from the airway centerline, then turn left to track parallel the original route, then climb or descend to the new level, and then return to the original route (when appropriate). When returning to the original route, be aware of conflicting traffic on that airway.
Weather Deviation Procedures • Altitude deviation due to severe turbulence or Mountain Wave Activity (WMA). When an aircraft experiences severe turbulence and/or mountain wave activity, which results in an altitude deviation of approximately 200 FT or greater, the pilot shall immediately notify ATC and state "Unable RVSM due turbulence / mountain wave activity". If not immediately issued by the controller, request vectors or heading away from traffic at adjacent flight levels. Report the location and magnitude of the turbulence or MWA to ATC as soon as practical. • Track Deviation for Weather. If a track deviation for weather is required and an ATC clearance cannot be obtained the following procedures shall be followed: 1. if possible deviate away from an organised track system. Broadcast intentions on 121.5 MHz and the air to air frequency 123.45 MHz. All available exterior lights should be selected on and the TCAS monitored for conflicting traffic 2. if the deviation is less than 10 NM, the aircraft should remain at the level allocated by ATC 3. if the deviation is greater than 10 NM, when the aircraft is 10 NM from track, initiate a level change based on the following criteria: Route Centre Line Track Deviations > 10 NM Level Change EAST 000-179 magnetic LEFT RIGHT DESCEND 300 FT CLIMB 300 FT WEST 180-359 magnetic LEFT RIGHT CLIMB 300 FT DESCEND 300 FT
When returning to track, be established at the previously assigned level when the aircraft is within approximately 10 NM of the centre line.
Reporting of Deviation from Cleared Flight Level If a flight deviates by more than 300 FT