Guidance concerning Air Navigation in and above the NAT MNPSA
En route Contingencies
Dispatchers must also be aware of special procedures for In-Flight contingencies as
published in Chapter 12 of this manual. They include procedures for use in the event that the aircraft is unable to maintain assigned altitude for weather, turbulence, aircraft performance or maintenance problems or loss of pressurization. The general concept of the in-flight contingency procedures is to offset from the assigned track by 15 NM and climb or descend to a level differing from those normally used by 500 ft if
below FL410 or 1000 ft if above FL410.
Procedures for loss of communications and HF failure are contained in Chapter 6 at
paragraphs 6.6 of this manual.
Dispatcher guidance for NAT RVSM operations.
The FAA Guidance AC91-85 was developed by ICAO sponsored international working
groups, to provide guidance on airworthiness and operations programmes for RVSM.
recommended that State CAA's use FAA Guidance AC91-85 or an equivalent State document for of aircraft and operators to conduct RVSM operations. Appendices 4 and 5 of AC91-85 contain and procedures for pilots and dispatchers involved in RVSM operations. This particular dispatcher
approval practices guidance
was developed using those appendices as the reference. This document http://www.faa.gov/about/office_org/headquarters_offices/ato/service_units/enroute/rvsm/
NAT RVSM Airspace This is defined as any airspace between FL 285 - FL 420 where 1,000 ft vertical separation is applied (i.e. FLs 290 thru 410 inclusive).
Limits of Operational Authorisation At the flight planning stage, the dispatcher is responsible for selecting and filing a route that is consistent with the carrier’s operational authorisation (e.g. Operations Specifications), taking account of all route, aircraft and weather considerations, crew constraints and other limitations.
MEL When planning and filing to fly within NAT RVSM airspace, the dispatcher must ensure that the route meets the requirements of the paragraph above and that the aircraft also meets certain MEL provisions.
TCAS (Traffic Collision Avoidance System)/ACAS (Airborne Collision Avoidance System) Aircraft operating in the MNPS are required to have TCAS/ACAS installed. However, MEL relief is provided for inoperative TCAS/ACAS, for dispatch into MNPS Airspace. TCAS/ACAS improves operational safety by enhancing pilot situational awareness and by providing a system for collision avoidance – particularly in densely populated airspace.
Note: For flights in the North Atlantic Region ACAS II (TCAS Version 7.0) has been mandated as a requirement since January 1, 2005 for all aircraft having more than 19 seats or a certified take-off mass of more than 5,700 Kgs. (Other standards may be in effect in other parts of the world) However, there are provisions for MEL relief.
NAT Doc 007