Air Traffic Management Concept Baseline Definition - The Boeing ...

(i.e., Great Circle tracks) have been introduced progressively to save fuel and time by
avoiding the inherent detours of fixed routes (e.g., National Route Program and random
routes/User Preferred Trajectories). Fixed track routings have been retained where the
traffic distribution must be kept simple and/or the number of crossing points in a sector
kept well defined.
5.3.4 Landing and Surface Operations
The ILS navigation aids (i.e., localizer and glide slope) provides lateral (from 25 nm out)
and vertical guidance (from 10 nm out) to the runway. Marker beacons or DME navaids
indicate the distance to the runway threshold. Precision Approach Minimums range from
CAT I to CAT III operations as a function of Decision Height (DH) and Runway Visual
Range (RVR). CAT I requires 200 feet DH and 1800 to 2400 feet RVR minima
depending on lighting system and airplane speed category, CAT III requires a DH between
0 and 50 feet and an RVR from not less than 700 feet (CAT IIIA) to not less than 150
feet (CAT IIIB). The ILS performance is limited in some areas by FM frequency
interference, in-band congestion, and siting limitations (an ILS site requires the
surrounding terrain to be flat so that signal characteristics are not distorted). Hence, the
Microwave Landing System was developed to the same performance requirements as ILS.
The FAA’s MLS development contract ran into production problems in the late 1980s and
was later canceled. It has been replaced with the Local Area Augmentation System
(LAAS) program which is a GPS-based landing system augmented with ground
augmentation aids. LAAS performance will include coverage for multiple runways or
airports in a regions. Airplane avionics are being developed to carry a Multi-Mode
Receiver (MMR) able to interface the crew controls and displays with one of several
receivers, either ILS, MLS or GPS Landing System (GLS).
5.4 Surveillance
5.4.1 Summary of Surveillance Evolution
The current surveillance system is based on the use of redundant primary and secondary
(beacon) radars. The role that ground based radars play may be gradually diminished as
GPS-based ADS 1 systems become available. The evolution to next generation
surveillance is complicated by interoperability and compatibility with current systems in
use. Two principles which limit available options for next generation systems are:
• Compatibility with current secondary radar systems, i.e. Mode A/ C/ S
• Interoperability with current TCAS collision avoidance systems and next generation
Cockpit Display of Traffic Information (CDTI)-based air/air surveillance and situation
awareness
1 In this section ADS is referred to in a generic sense rather than as a specific implementation. In this sense,
Mode-S Specific Services, Mode-S extended squitter broadcast and contract based ADS as defined by RTCA
DO-212 represent specific implementations of ADS technology.
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