Gulfstream G650ER Horizontal Stabilizer Control System Description PDF

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

GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL HORIZONTAL STABILIZER CONTROL — SYSTEM DESCRIPTION 1. General A. Description The Horizontal Stabilizer Trim System (HSTS) provides electrical and mechanical control of the stabilizer, fault monitoring and annunciation. This system is considered a subsystem of the Primary Flight Control System (PFCS). The HSTS is an integrated system that provides supplemental pitch control functionality. See Figure 1. The HSTS consists of the following three main components: Horizontal Stabilizer Control Unit (HSCU) Horizontal Stabilizer Trim Actuator (HSTA) Wiring harnesses between Flight Control Computers (FCCs), HSCU and HSTA During flight, the horizontal stabilizer works in conjunction with the FCCs and elevators. The HSTA is trimmed via FCC rate command input such that the elevators remain within a specified tolerance of the faired position. This is called the elevator off-load function. The horizontal stabilizer is mounted in a T-configuration on top of the vertical stabilizer and pivots to change the angle of incidence as flaps are extended or retracted. 2. Subsystems Horizontal Stabilizer Actuation, 27-43-00, System Description Horizontal Stabilizer System Sensors, 27-44-00, System Description Horizontal Stabilizer System Electronics, 27-45-00, System Description 3. Subsystem Details A. Horizontal Stabilizer Trim Actuation The HSTA is a dual load path ballscrew actuator powered by two redundant DC electric motors. Each HSTA motor is fully capable of driving the stabilizer and is controlled from one of two HSCU channels. The HSTS converts three-phase 115 Vac from the right main ac and emergency ac buses to 270 Vdc, pulse width modulated power to drive the HSTA. The 270 Vdc motors are torque summed and drive the HSTA ballscrew in an active standby configuration via inertial clutch and gear train. The dual channel HSCU monitors and controls the HSTA. Each HSCU channel has one command and one monitor lane. Each HSCU channel receives rate commands from one FCC over a standard ARINC 429 bus. The more capable HSCU channel controls the HSTA. Each channel of the HSCU provides the electronic drive for one electric motor and control of two motor brakes. If there is a failure in the two FCC to HSCU buses, the HSCU takes its commands from the BACKUP PITCH trim switches located on the pedestal. B. Horizontal Stabilizer System Sensors There are two independent dual channel position resolver sensors that provide feedback to the HSCU. The HSCU converts the resolver signal to a stabilizer position. This position is transmitted via ARINC 429 interface to the FCCs and Modular Avionics Units (MAUs) for use in the control law and primary flight display indication. There are two resolvers in each motor that provide feedback to the HSCU. The sensors provide data used to determine the motor rate. This rate is used by the HSCU to verify the system performance and health is within specifications. 27-40-00 Page 1 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL C. Horizontal Stabilizer System Electronics The HSCU is installed in the baggage EER and receives rate commands from the FCCs. The HSCU is a dual channel controller that operates in an active / standby configuration. It interfaces with the following systems: Aircraft electrical power system Broadband multilink antenna control unit PFCS through the FCCs CAS through the MAUs Central Maintenance Computer (CMC) through the MAUs Cockpit through the control wheel and pedestal BACKUP PITCH trim switches The HSTS is an integrated system that provides supplemental pitch control functionality. The HSTS is a fully trimmable system installed as part of the aircraft tail. The stabilizer surface is moved by the HSTA. The motor and braking system on the HSTA receives command inputs from the HSCU. Horizontal stabilizer modes are related to the FCC mode. If the FCCs are in their normal in-air mode, the horizontal stabilizer isin its normal mode. Under those conditions, the stabilizer is rate commanded by the FCC to off load the elevators. The BACKUP PITCH trim switches (controlled by the pilot) move the elevators and not the stabilizer. While aircraft is on ground and stationary, the HSTA is controlled directly through the FCC via the BACKUP PITCH trim switches. (1) Normal Control Normal control is provided via the FCC rate commands to the HSCU. The FCC provides valid calculated rate commands. The HSCU is capable of performing the necessary control and monitoring to ensure safe operation. In normal mode the HSCU operates in active / standby configuration. Both channels receive commands from the FCCs. Both channels calculate commands. Only the active channel controls the HSTA. The HSTS operates in normal mode when the FCCs are available and the HSCU is available. The HSTS operates in normal mode whenever possible. If the FCCs are in either direct or alternate mode and communication is valid between the FCCs and the HSCU, the stabilizer will remain in its normal mode. Stabilizer control is by direct pilot input from the BACKUP PITCH trim switches. It is still controlled through the FCC, which provides two fixed command rates. NOTE: There is no direct pilot control of the stabilizer in normal mode. (2) Secondary Control Secondary control is provided via the BACKUP PITCH trim switch located on the pedestal. A Stab Primary Trim Failed (amber) message is provided via CAS to alert the crew that the HSTS is in secondary mode. Inputs to the switch are provided directly to the HSCU. The HSCU provides a minimum rate input to the HSTA. The HSTS enters secondary mode following loss of valid FCC communication for greater than 1 second. The HSTS will up-mode to normal mode when either FCC provides three consecutive frames of valid data. (3) Maintenance Maintenance mode is used to perform system rigging, perform Initiated built-in test, or perform troubleshooting on the HSTS. The HSTS operates in maintenance mode when all interlocks are valid. The following defined interlocks are: Maintenance requests from the CMC Valid on ground and stationary interlock from the FCC Valid flight control system maintenance switch from the FCC 27-40-00 Page 2 August 15/14 GULFSTREAM G650ER SYSTEM DESCRIPTION MANUAL 4. Operational Summary A. Horizontal Stabilizer Control In normal mode, the FCCs receive trim commands from the control wheel trim switches or from the trim control panel switch on the pedestal. The FCCs provide rate commands to the HSCU in accordance with the FCC control laws. 27-40-00 Page 3 August 15/14