HORIZONTAL STABILIZER SYSTEM ELECTRONICS.pdf

GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL HORIZONTAL STABILIZER SYSTEM ELECTRONICS — SYSTEM DESCRIPTION 1. General A. Description The Horizontal Stabilizer Trim System (HSTS) provides electrical and mechanical control of the stabilizer, fault monitoring and annunciation. The HSTS is a fully trimma...

GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL HORIZONTAL STABILIZER SYSTEM ELECTRONICS — SYSTEM DESCRIPTION 1. General A. Description The Horizontal Stabilizer Trim System (HSTS) provides electrical and mechanical control of the stabilizer, fault monitoring and annunciation. The HSTS is a fully trimmable system installed as part of the aircraft tail. The stabilizer surface is moved by an electric, dual load path Horizontal Stabilizer Trim Actuator (HSTA). This system is considered a subsystem of the Primary Flight Control System (PFCS). See Figure 1. The motor and braking system on the HSTA receives command inputs from the Horizontal Stabilizer Control Unit (HSCU). The HSCU is installed in the baggage compartment EER and receives rate commands from the Flight Control Computers (FCCs). The FCCs receive trim commands from the control wheel trim switches or from the trim control module switches located on the pedestal. If the FCCs fail, the trim control module lets the pilot / copilot input commands directly to the HSCU, bypassing the FCCs. 2. Component Location COMPONENT ATA QTY PER A/C LOCATION Horizontal stabilizer control unit 27-45-01 1 Forward baggage EER 3. Component Details A. Horizontal Stabilizer Control Unit The HSCU is a dual channel, active / standby controller that interfaces with the PFCS through the FCC and also with the BACKUP PITCH trim switches on the trim control module. The HSCU is a six module control unit that is electrically bonded to the aircraft structure through the HSCU mounting tray. The HSCU is part of the horizontal stabilizer system electronics. There is a single ARINC 600 connector in the rear of the unit. The following systems interface with the HSCU: PFCS through the FCCs CAS through the Modular Avionics Units (MAUs) Central Maintenance Computer (CMC) through the MAUs Cockpit through the trim control module switches The HSCU has two mechanically and electrically separate control channels, each channel uses a hardware and software dissimilar command / monitor architecture. The HSCU dual channels are identical, with the exception of an ARINC 429 (A429) transmit bus from HSCU channel 2. The A429 transmit bus goes to the aircraft antenna control unit to provide the horizontal stabilizer position. In normal operation, the FCCs sends rate commands to the HSCU to close the rate loop. The HSCU provides position and rate feedback that allows the FCCs to close the position loop. The HSCU also provides A429 input to MAU No. 1 and MAU No. 2 for CAS display and CMC maintenance information. A cross-channel bus, routed in a harness exterior to the HSCU, contains position information for power-up built-in testing. If both FCCs fail, the HSCU uses commands from the trim control module switches, bypassing the FCCs, to provide trim commands directly. The HSCU includes two each of the following major subassemblies: Signal Conversion Unit (SCU) Motor Drive Unit (MDU) 27-45-00 Page 1 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL Each HSCU has a dual lane design. Each lane, designated lane 1 and lane 2, independently performs its own function in a command / monitor arrangement. Motor commands are only provided from lane 1. Each SCU generates commands, monitors motion and provides high integrity horizontal stabilizer position data for its designated channel. Each HSCU channel contains an MDU, capable of controlling one of two HSTA motors. Both motors are fully capable of operating the actuator in the normal mode. As long as both motors and monitoring systems are fully functioning, the HSCU uses switching logic to alternate operation of each channel and motor at power up. Each MDU within the unit contains a Transformer/Rectifier Unit (TRU) that converts three-phase, 115 Vac to 270 Vdc for powering HSTA motors. The TRU uses a 12 pulse autotransformer, mediating choke and filters to generate regulated 270 Vdc from the aircraft 115 Vac power source. The secondary of the transformer is rectified by two diode bridges. The bridges are in parallel and provides 270 Vdc to the power bridge. The SCU uses a 115 Vac valid discrete output from the TRU to determine if an actuation fault is caused by a system fault or low 115 Vac power. The MDU is a high power, high voltage electronic motor controller designed to drive the HSTA motor brake. The MDU is packaged as a single channel module integral to the HSCU. There is one MDU per HSCU channel, dedicated to drive one motor brake. The MDU includes the following: A lightning filter to prevent over voltages due to lightning strikes Internal power circuitry Hall effect current sensors Speed and motor torque control electronics The MDU is contained in a machined aluminum enclosure that is environmentally sealed and independent from the SCU. The MDU portion is cooled by convection and radiation from the cooling fins provided on both sides of the unit. 4. Controls and Indications A. Circuit Breakers The system is protected by the following circuit breakers: NOMENCLATURE PANEL LOCATION POWER SOURCE STAB 2 DC REER A7 R ESS 28VDC STAB CH 1 REER E1 EMERG BUS 115VAC STAB 1 DC LEER B10 L ESS 28VDC STAB CH 2 PDB PDB / EER R MAIN BUS 115VAC B. CAS Messages The CAS messages for the system are shown in the following table: MESSAGE COLOR MESSAGE DESCRIPTION Stabilizer Rigging Complete Blue Rigging is valid for the current aircraft. Message occurs when in maintenance mode after autorigging is satisfactorily completed. No action required. Stabilizer Maintenance Required Blue The HSCU has flagged a maintenance item. System redundancy has not been lost. 27-45-00 Page 2 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL MESSAGE Stabilizer Failed COLOR Amber MESSAGE DESCRIPTION Horizontal stabilizer not responding to movement commands or surface position information is unreliable or unavailable. If flight control system is in normal mode, PITCH trim switch on control wheel adjusts elevator trim position. NOTE The backup pitch trim switch on the trim control module shall not be used. Stabilizer Channel Fail Amber A horizontal stabilizer control channel has failed. Notify maintenance for corrective action. Loss of valid pitch trim communication from the FCCs to the HSCU. Continue flight using BACKUP PITCH trim switch. PITCH trim switch on control wheel will be inoperative. Stabilizer Primary Trim Fail Amber NOTE This message may be accompanied by FCC Alternate Mode (amber). NOTE: The FCC status information required by the flightcrew is shown on the main displays as CAS messages and synoptic page data. 5. Operation A. Horizontal Stabilizer System Electronics The HSCU electrically limits the stabilizer surface travel to a maximum of 0.75° leading edge up and 10.75° leading edge down. If the HSCU fails to provide electrical stops to the stabilizer travel, mechanical stops in the actuator limits stabilizer travel. The HSCU will perform the HSTS monitoring function when in normal or secondary mode. The HSTS monitoring will able to detect and isolate HSTS failures and provide failure annunciation to the flight and maintenance crews. If both FCCs fail, the HSCU uses commands from the trim control module switches located in the pedestal. Commands from the trim control module switches go directly to the HSCU, bypassing the FCCs. 27-45-00 Page 3 August 15/14