Analysis of advanced flight management systems (FMS), flight management computer (FMC) field observations trials, vertical path

Abstract

The differences in performance of various manufacturers' Flight Management Systems (FMSs) and their associated Flight Management Computers (FMCs) have the potential for significant impact on the air traffic control system. While Area Navigation (RNAV) and Required Navigation Performance (RNP) procedures and routes are designed according to criteria contained in Federal Aviation Administration (FAA) orders, FMCs are built to meet Minimum Aviation System Performance Standards (MASPS) [1] and the Minimum Operational Performance Standards (MOPS) [2] for area navigation systems, Technical Service Orders and Advisory Circulars. The expectation is the resulting performance of the aircraft FMC will meet the procedure design requirements identified in the FAA criteria. The airspace design goal is procedures where aircraft operations result in repeatable and predictable paths. However, actual aircraft performance frequently does not match the expectations of the procedure designer. Studies referenced in this paper such as Assessment of Operational Differences Among Flight Management Systems [3], Analysis of Advanced Flight Management Systems (FMSs) [4] and Analysis of Advanced Flight Management Systems (FMSs), FMC Field Observations Trials [5] have shown that these differences result from variations in FMS equipment; variations and errors in data collection and processing; variations in pilot training and airline operating procedures; and variations in aircraft performance. This paper presents the hypothesis that given a standardized performance-based (RNAV/RNP) procedure with coded altitudes, variations in vertical path performance will exist among the various FMC/FMS combinations that are tested. Controlled observations were made using twelve different test benches at five major FMC manufacturers and three full-motion simulators at the FAA and two airlines. This focus on vertical navigation (VNAV) path conformance follows the MITRE Corporation's analysis of lateral navigation (LNAV) path Conformance described in Analysis of Advanced Flight Management Systems (FMSs), FMC Field Observations Trials [5].

Use of aircraft intent data for Performance-based ATM operations

“…It is also expected that differences in FMS algorithms (e.g., [26,27]) will occur in the way the wind data is applied. This lack of consistency would cause problems with conflict detection between ai a simple in-trail situation, where aircraft flying at the same, level altitude and the same airspeed should maintain their spacing.…”

“…When the aircraft has a turn before segment for which the plann the ed airspeed ling is desired, differences in turn mode between FMSs [26] will cause ETA differences that would cause errors in the inferred airspeed. Transmission of detailed turn information (e.g., as outlined below) would serve to eliminate much of this error.…”

Analysis of Advanced Flight Management Systems (FMS), Flight Management Computer (FMC) field observations trials: Area Navigation (RNAV) holding patterns

“…Aircraft to FMC interface and associated aircraft performance capabilities 4. Flight crew training and procedures Subsequent papers were published in: 2006, [3]; in 2007, [4]; in 2008, [5]; in 2009, [6]; and in 2010, [7]. Each of these reports explored the FMC equipment installed on the aircraft and how the equipment processed lateral, vertical, and specific radius-to-fix (RF) paths.…”

New Search Space Reduction Algorithm for Vertical Reference Trajectory Optimization

“…Researchers have been particularly interested in FMSs; investigating their evolution and their role in the future, including the role they play in various aircraft tasks 14,15 . Specifically, studies have focused on their performance of current functions, measuring the capacity of the FMS to intercept and follow waypoints 16,17 and the capacity of this device to follow a time imposed trajectory during descent 18 , one of the functions required for the next generation of FMSs.…”