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B737 GPS/FMS. Part 2: B737 Installation. Topics Introduction Canadian Marconi CMA-900 Aircraft Integration System Interfaces Flight Deck Interfaces System Operation. Canadian Marconi CMA-900.
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B737 GPS/FMS Part 2: B737 Installation
Topics • Introduction • Canadian Marconi CMA-900 • Aircraft Integration • System Interfaces • Flight Deck Interfaces • System Operation
Canadian Marconi CMA-900 The Canadian Airlines B737 is being equipped with a Canadian Marconi CMA 900 Global Positioning System/Flight Management System (GPS/FMS). This FMS has a number of important characteristics. It is certified as a TSO C129 A1 Receiver. This level of certification offers the following capabilities: • all phases of flight including enroute, terminal and and GPS based non-precision approach operations • it is a “stand-alone” GPS receiver meaning no other sensors such as DME/DME updating or INS/IRS are required • it is approved for Primary-means Oceanic and Remote operations
The CMA 900 as a Flight Management System offers: • SID/STAR navigation • GPS instrument approach capability • direct-to navigation with leg and course intercepts • fly-by and fly-over waypoints transitions • parallel offset tracks • holding pattern navigation • DME arcs and procedure turns • company routes • extensive navigation database • navigation with reference to true or magnetic • Required Time of Arrival (RTA) • Required Navigation Performance (RNP) • A Multi-function Control and Display Unit (MCDU) capable of hosting ACARS
Other features that will be available in the future include: • Geometric vertical navigation (VNAV) • ACARS flight plan data link • Future Air Navigation System (FANS) • Differential GPS including Wide Area Augmentation System (WAAS) and Local Area Augmentation System (LAAS)
GPS Antenna’s There are two GPS antenna’s - one for each Flight Management Unit -located on the upper surface of the aircraft. GPS signals received by the antenna’s are sent to their respective Flight Management Unit located in the E & E compartment.
The Flight Management Unit serves a multitude of purposes: • integrates and processes information from GPS sensor, aircraft interfaces and crew (via MCDU) • generates outputs including steering commands and display information • houses the GPS Sensor which is the heart of the FMS. The GPS sensor is a twelve channel device meaning that twelve GPS satellites can be tracked simultaneously.
Multi-function Control Display Unit (MCDU) The MCDU is the primary pilot interface with the FMS. Each pilot has an MCDU located on the forward electronic panel. The MCDU’s use a similar operating philosophy to the Boeing and Airbus MCDU’s with a scratchpad and line select operation. The display is an Active Matrix Liquid Color Display (AMLCD) with a full alphanumeric keyboard and 14 line select keys
Flight Deck Installation The B737 GPS/FMS installation is certified for IFR operations including enroute, terminal and non-precision approach applications. The B737 utilizes as fully dual installation: dual antenna’s, dual FMU’s and dual MCDU’s. The system is designed to operate by default in a fully synchronized mode between the two independent systems.
In the synchronized mode, flight-plans, system position, status and other data are automatically transferred between the systems. Key system position and sensor status data are compared, and alert messages are generated when discrepancies are detected. Initialized system position, date/time, database cycle selection, altimeter setting, and other system reference selections are synchronized at all times. Flight plans are transmitted automatically to the cross-side system on activation and on execution of any modification. Each MCDU can control both FMU’s or each FMU can be interfaced with the two MCDU’s thus provided multiple failure operational redundancy. When a failure or degraded performance is detected, the system reverts to independent mode of operation. When operating in independent mode, flight plan transfer can be initiated manually by a line select key operation.
System Interfaces A number of aircraft systems are interfaced with the FMU. These are: • Air Data Computer • provides True Airspeed (TAS) and altitude • barometric corrected altitude is provided by manually entering the barometric altimeter setting and will be modified for automatic operation later • Heading • the aircraft heading is provided to determine drift and compute the wind vector and to fly aircraft headings during FMS operations • Fuel Flow (used for future upgrade) • when implemented, computed fuel at waypoints will be provided
Discrete inputs • Take-off and Go Around switches (throttle quadrant) are sensed and are used to initiated a missed approach in the FMS • Air/ground sensor is used to sense when the aircraft is airborne. This is used to record airborne and landing times in the FMS
Annunciator Bank Each pilot is provided with an Annunicator bank, located under their respective RMI. This device provides annunication of of GPS status as well as a means to control whether VOR/LOC or FMS steering information is being provided. The light test will illuminate the annunciator bank. The bright/dim selection will increase or decrease the lighting intensity
HSI Source Select Switch Located on the annunciator bank, this momentary switch determines the source of track guidance that will be presented on the HSI and, when used in conjunction with the LNAV/VNAV switches, determines the source for the autopilot and flight director
With “VOR/LOC” selected, navigation information from the VHF nav is sent to the HSI; the FMS does not provide steering guidance to the autopilot or flight director With “FMS” selected, navigation information from the FMS is sent to the HSI and the FMS provides steering guidance to the autopilot or flight director when “LNAV” is selected
LNAV/VNAV Switches These switches are located under the dash board near the master caution annunciators • allows autopilot and flight director to be engaged to FMS guidance • FO does not have VNAV controls • the “LNAV” is constantly illuminated • the light test can be used to verify the “ON” • “LNAV” intensity is controlled by individual panel dimming controls • “ON” intensity is controlled by the bright/dim switch
With LNAV not selected, the autopilot and flight director cannot receive FMS steering information With LNAV selected and HSI source selected to FMS, the autopilot and flight director can receive FMS steering information
Autopilot/Flight Director Both the autopilot and flight director have been modified to accept FMS steering guidance. Autopilot: the “HDG SEL” on the Autopilot Heading Switch has been modified to “LNAV/HDG SEL”. The autopilot can be used for FMS LNAV under the following conditions: • Captain’s HSI Source Select: FMS • Autopilot Heading Switch: LNAV/HDG SEL • LNAV Switch: ON
Flight Director: the “HDG” selection on the Flight Director Mode Selector has been changed to “LNAV/HDG”. The flight director can be used with the FMS LNAV under the following conditions: • HSI Source Select: FMS (respective side, I.e. Captain or First Officer) • Flight Director Mode Selector: LNAV/HDG • LNAV Switch: ON Note: Since the flight director will only operate with the FMS in the “LNAV/HDG” mode, the selection of other flight director modes (VOR/LOC, AUTO APPR, APP MAN) with the HSI Source Select in “FMS” will result in a Computer Flag being displayed on the ADI.
Approach Progress Display The approach progress display works in a similar manner to current APD applications. When the path is captured the annunciator changes to green. In the case of the FMS, the amber (armed mode) does not exist. When LNAV is selected the system immediately “captures” the path and a green annunciation takes place.
Annunciator Bank The annunciators provide status indications; they also provide warnings when a system failure is detected.
Horizontal Situation Indicator The HSI will display track guidance from the FMS when the HSI Source Select is in “FMS”. The following information is displayed on the HSI: • Course deviation with the track bar • TO/FROM pointer associated with the waypoint • Warning Flags if course information is invalid
Distance to the waypoint on the distance display is presented in 10’s, 1’s and 1/10th’s of miles • With the HSI Source Select in VOR/LOC, the distance flag will cover the distance to go display NOTE: the HSI course selector is not automatically slaved to the FMS. After passing each waypoint, the course bar will have to be manually changed to reflect the new course
HSI Sensitivities The FMS uses default, full scale deflection HSI sensitivities, depending on the phase of flight. These are: Enroute 5 nm Terminal 1 nm Approach 0.3 nm These are displayed on the MCDU PROG page 1/4
VHF Nav Operation To operate the aircraft in the VHF Navigation mode (VOR or ILS), the following selections are required: • HSI Source Selection: VOR/ILS In this mode, the HSI operates normally, the autopilot operates per AOM Chapter 7 and the flight director per AOM Chapter 19
FMS Operation To operate the aircraft with the Flight Management System providing lateral navigation information the following selections are required: • HSI Source Selection: FMS • if desired, Autopilot Heading Switch: LNAV/HDG SEL • if desired, Flight Director Mode Selector: LNAV/HDG • LNAV Switch: ON • Note: The Capt’s HDG marker should be set on the desired HDG; if LNAV is selected off when the A/P is selected to LNAV/HDG SEL the A/P reverts to Heading Select.