ANALYSIS OF ADV ANCED FLIGHT MANAGEMENT SYSTEMS (FMS), FLIGHT MANAGEMENT COMPUTER (FMC) FIELD OBSERV ATIONS TRIALS; STANDARD INSTRUMENT DEPARTURES
Albert A. Herndon, Michael Cramer, Tommy Nicholson and Sam Miller The MITRE Corporation’s Center for Advanced Aviation System Development
McLean, Virginia
Abstract
The differences in performance of various manufacturers’ Flight Management Systems (FMSs) and their associated Flight Management Computers (FMCs) have the potential for significant operational impact on the air traffic control system and as such need to be examined on a recurring basis.
Performance-bad navigation (PBN) is a fundamental principle for aircraft operations that will facilitate the transition to future airspace systems. A critical element of PBN is the FMS’s capability to fly a consistently repeatable and predictable flight path trajectory that will meet the expectations of air traffic control.
FMS manufacturers build their systems in accordance with [1] and [2] for area navigation systems, Tec
hnical Standard Orders and Advisory Circulars. Area Navigation (RNAV) and Required Navigation Performance (RNP) procedures and routes are published by the Federal Aviation Administration (FAA) according to criteria contained in FAA orders. It is anticipated that the resulting performance of the aircraft FMC will meet the procedure design requirements identified in the FAA criteria.验货单
Sometimes, due to the nearly independent development of procedure design criteria and aircraft performance standards, the paths of various aircraft on the same procedure do not coincide and therefore do not match the expectations of the procedure designer. The differences may result from any or all of the following: variations in FMC equipment installed on the aircraft; variations and errors in procedure coding in the FMC navigation databa; variations in aircraft-to-FMC interface and associated aircraft performance capabilities; and variations in flight crew training and procedures.
The hypothesis of this paper is that the FMCs built by avionics manufacturers and installed as the core of the FMC/FMS combinations in various airframe platforms perform differently and we will attempt to quantify tho differences. This paper focus on FMC performance when flying Standard Instrument Departures (SIDs) and their associated waypoints and leg types (path terminators) and combinations as described in [3]. Public instrument procedures flown using RNAV
equipment are ud as the baline for measuring the performance variations.
Controlled field obrvations trials were made using twelve FMS test benches and three simulators at ven major FMC manufacturers and two airlines. Analysis of data from the trials confirms differences and the details are prented. The intent of this report is to contribute technical data as a foundation for the acceptance of required navigation performance (RNP) departures. Introduction
The FAA is committed to transitioning to a performance-bad National Airspace System (NAS). PBN is defined as navigation along a route, procedure, or within airspace that requires a specified minimum level of performance for system elements. Key concepts of this PBN system are bad upon RNAV and RNP involving terminal SIDs, Standard Terminal Arrivals (STARs), Instrument Approach Procedures (IAPs), and en route and oceanic procedures.
The MITRE Corporation’s Center for Advanced Aviation System Development (CAASD) has supported the FAA in identifying and analyzing differences among widely ud operational FMSs and in particular their associated FMCs. The FMC is the core of the FMS and performs the navigation calculations. This report is part of a continuing
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effort beginning with [4] in 2004, to focus on the differences in how aircraft using different FMSs/FMCs execute specific procedures resulting in different trajectories being flown by the aircraft.
In 2005, [5] reported that there are four primary areas that contribute to variations in the aircraft RNAV/RNP paths:
1.FMC equipment installed on the aircraft
2.Procedure coding (errors) in the FMC
navigation databa
3.Aircraft to FMC interface and associated
aircraft performance capabilities
4.Flight crew training and procedures
Subquent papers were published in: 2006, [6]; in 2007, [7]; in 2008, [8]; and in 2009, [9]. Each of the reports explored the FMC equipment installed on the aircraft and how the equipment proces
d lateral, vertical, and specific radius-to-fix (RF) paths. This 2010 paper reports on combinations of leg types (paths and terminators)1 and associated waypoints that currently may be ud in public SIDs.
An extensive trial and data collection plan was developed to facilitate the trials while also attempting to ea the data collection effort for the manufacturer or airline. Manufacturers do not typically allow access to their developmental and test areas; however, agreements were developed to treat the data as proprietary and to disassociate analysis and reporting from the manufacturer’s name. As a result, data from major flight management computer avionics manufacturers and airlines was obtained. The data was analyzed and the results are compiled in this document. Scope
This paper describes lateral and vertical paths computed by FMS’s. The data was obtained from twelve test benches and three simulators at ven major FMC manufacturers and two airlines. It reports on the development, conduct, results and analysis of the Field Obrvations Trials plan which took place between February and May, 2010.
1 ARINC 424 [3] Background
Since the FAA began the development and implementation of RNAV procedures veral years ago,
air traffic controllers have developed an expectation that the u of RNAV and RNP procedures would result in more accurate and predictable paths and less pilot-controller communications. It was also expected that the paths would be more uniform across the fleet mix and not vary as much per aircraft type. For the most part, RNAV and RNP procedures have achieved the goals, but due to differences in aircraft ground speeds and variations in the performance of FMCs, track conformance has not met tho expectations. As procedures were implemented at different locations, it was identified almost immediately that while on RNAV procedures, aircraft flying at different speeds and with different FMS equipage do not all fly lateral paths the same way, nor do they turn or climb or descend at the same points in space. The first obrved differences involved lateral path construction and then as vertical path construction were included in the investigations, vertical differences were also obrved. Differences, especially differences in lateral and vertical path were extensively explored by the authors of this paper. The exception was radius-to-fix paths where the lateral path was consistently predictable and repeatable for all manufacturers.2 In the constantly changing world of PBN the task of guidance, or the FMS control of the lateral and vertical profile, and the capability of the associated FMCs to comply with speed and altitude constraints at waypoints continues to be an important topic for investigation. Variations in FMC equipage are not only a problem caud by the differences in types of aircraft, where varied performance capabilities
bad on airframe and engines are expected, but many times the same model of aircraft may also exhibit variations in performance. The differences may result from an aircraft manufacturer’s u of different FMCs in the FMSs.
This paper’s goal is to investigate SIDs, as constructed in accordance with [10], from airports in the NAS that contain combinations of leg types and waypoints that are of interest in better
2 Herndon et al. [6, 7, 8 & 9]
understanding FMC behavior when processing the combinations. They are also of interest to FAA Flight Standards, the FAA RNAV/RNP Group and industry in continuing work to establish RNP departure criteria. The departure leg types of particular interest were cour-to-fix (CF), heading to altitude (VA), heading to intercept (VI), direct-to-fix (DF), track-to-fix (TF), heading to distance measuring equipment [DME] distance (VD), and the combinations of such leg types along with both fly-by (FB) and fly-over (FO) waypoints. The various leg types and waypoints are explained as follows:
Leg Types3
1.Cour-to-fix (CF)
a.“A specified cour to a specific
databa fix.”
2.Heading-to-altitude (VA)
a.“A specified heading to a specified
altitude termination at an
unspecified position.”
表达方式的作用3.Heading-to- intercept (VI)
a.“A specified heading to intercept
the subquent leg at an
unspecified position.”
4.Direct-to-fix (DF)
a.“An unspecified track starting
equilibrium
from an undefined position to a调度室
specific databa fix.”
5.Track-to-fix (TF)
a.“A great circle track over the
ground between two known
databa fixes.”
6.Heading-to-DME distance (VD)
a.“A specified heading terminating
at a specified DME distance from
新标准英语第三册a specific databa DME Navaid.”
DME Navaid is defined as a
navigation aid that provides
distance from that aid measured in
nautical miles.英语六级总分
Waypoints4
3 ARINC 42
4 [3]
1.Fly-by waypoint
a.“A waypoint where a turn is
initiated prior to reaching it.”
2.Fly-over waypoint
a.“A waypoint over which an aircraft
is expected to fly before the turn is
initiated.”
Four SIDs were lected for the trial:
1.DEBIE FIVE RNAV
DEPARTURE, Rwy 36R –
Charlotte/Douglas KCLT, NC
2.SKORR ONE RNAV
DEPARTURE, Rwy 31R - John F.
Kennedy KJFK, NY
3.BUCKEYE TWO DEPARTURE,
Rwy 25R – Sky Harbor KPHX, AZ
4.BARGN ONE RNAV
DEPARTURE, Rwy 08, Sky
Harbor KPHX, AZ
中考数学模拟试卷
Each of the procedures is described below. Field Obrvations Trial
Field obrvation trials were a key component of the data collection. To conduct the trials, a plan was developed and provided to the FAA and industry participants for approval. The excellent support received from the participants was esntial for the data collection. A list of the manufacturers, the versions of FMC models/software, and the range of aircraft reprented is discusd along with the lection of public procedures ud during execution of the trial plan.
Trial Plan Development
Starting with recommendations from previous analysis efforts, veral investigative areas were considered for this report. As mentioned in the Introduction, there are four primary areas that contrib
lenute to variations in the aircraft lateral and vertical paths: FMC equipment installed on the aircraft; procedure coding in the FMC navigation databa; aircraft to FMC interface and associated aircraft performance capabilities; and flight crew procedures:
4 FAA Order 8260.44A [10]
1. FMC equipment installed on the aircraft: variations of FMS equipage occur between aircraft models as well as within the same model. The same type of aircraft may have FMCs from different manufacturers and/or different FMC models from the same manufacturer. Also as expected, different types of aircraft will have FMCs from different manufacturers installed.
2. Procedure coding in the FMC navigation databa: different versions of ARINC 424 ud in the FMC, as well as databa suppliers interpretation and coding of a procedure, can have an impact on how the aircraft complies with the generated lateral navigation (LNAV) and vertical navigation (VNAV) paths.
3. Aircraft to FMC interface and associated aircraft performance capabilities: FMC manufacturers often supply their systems to different aircraft manufacturers. The same model FMC may be installed in an Airbus aircraft and
a Boeing aircraft where the aircraft performance requirements require the particular FMC model to be tailored. Some manufacturers offer differently tailored FMCs to different customers operating the same type aircraft. The different airframes when joined with different engine combinations will, as expected, have performance capabilities that differ. For example, frequently obrved differences include variations
in acceleration, climb rate, maximum allowable bank angle, etc.
4. Flight crew procedures: Airline flight crews and general aviation crews have extensive differences in training requirements and standards as well as different operating philosophies and procedures. For example, speed schedules may vary considerably and some flight crews may be instructed to u all available FMC, autopilot guidance and FMS automation provided while some operators explicitly limit what flight crews may u. The variations in flight crew operating
procedures have not been fully
examined.
Of the four areas, numbers two and three were examined previously5 and were found to have sig
nificant negative impacts on the repeatability of LNAV and VNAV paths. Bad upon recommendations in tho reports, the decision was made to focus on core functionality and examine differences in FMCs. Previous reports6 examined the lateral, vertical and specific radius-to-fix paths. The intention of this report is to examine aircraft tracking on a ries of procedures to accommodate the four stated goals for the trials.
The methods of the trial plan were to:
1.Control all pertinent variables through
standardized trial scenarios.
2.U public procedures that are in u in
the NAS today.
3.Incorporate as many different
manufacturers’ FMCs as possible.
a.U airline high fidelity simulators to
validate fixed-bad simulation
resources.
1.Facilitate the trials and data collection
process.
2.De-identify and protect the data provided
by the manufacturers.
To successfully accomplish the goal of the trials and directly compare different systems’ performance, unprocesd data needed to be obtained. This data can only be obtained from manufacturers’ test bench or test station computers (sometimes called System Integration Test Stations [SITS]), as all errors associated with atmosphere, nsors, and other peripheral systems can be eliminated, leaving the focus directly on the FMC. The “test bench FMCs” are only available in the rearch and development labs of the manufacturers. In addition, when necessary to fill equipment gaps, high fidelity airline simulators were ud. The authors recognize that most modern simulators u re-hosted FMC’s and therefore, the simulator data was vetted for accuracy b
efore u.
5 Steinbach [4] and Herndon et al. [5]
暮光之城3简介6 Herndon et al. [6, 7, 8 & 9]
Manufacturer/Airline Participation
Seven FMC manufacturers and two airlines agreed to participate in the trials and data collection effort. The ven manufacturers and the airlines’ FMCs provide over 95% of the civil FMC systems in rvice today. The high fidelity simulators and test bench obrvations involved simulating an aircraft flying public procedures with pre-determined parameters recorded for each flight. The same obrvation profile was accomplished at each manufacturing site and airline.
home workingParticipating manufacturers and airlines and their associated FMC models are prented in Table 1.
Table 1. FMC Test Benches/Simulators
Trial Plan
Previously proven plans7 were amended and prented to the airlines and each manufacturer to provide the required information to tup the FMC test facilities and collect the required data. The NAS was arched for public published SID procedures to satisfy the intentions stated previously. The following four were chon and the trial plan requested that each be flown honoring all charted restrictions.
1.DEBIE FIVE RNAV DEPARTURE,
Runway (RWY) 36R, at the
Charlotte/Douglas International Airport
(KCLT) in Charlotte, North Carolina.
Route description is climb heading 003
degrees to intercept cour 028 degrees
to KAYFO (flyover waypoint), then
left turn direct to KATSE. [3] coding is
VI – CF – DF. See Figure 1.
7 Herndon et al. [6, 7, 8 & 9]
