Agusta SpA, a Finmecanica Company, has selected Sextant to supply avionics systems for new A109 LUH helicopters being purchased by the South African Air Force. A firm order for 30 aircraft was placed, with an option for 10 additional units.
Sextant will supply a large portion of the helicopters' avionics including 6 x 8-in active-matrix liquid-crystal displays, a four-axis autopilot, a flight management system, GPS receiver, attitude and heading reference system, the air data system, the radio-altimeter, and the mission computer for military applications.
In addition to this program, the company has also been selected to supply its Meghas avionics suite for the French Gendarmerie's BK 117 C2 helicopters. Meghas has already been certified for the Eurocopter EC 120, Ecureuil B3, EC 135, and EC 155. Using the basic version already certified on the EC 135, Sextant will adapt the central panel display system and flight control display system to the BK 117 C2 environment. Deliveries of production-standard systems to the French Gendarmerie and civil security forces will begin sometime this year.
The Meghas system handles main helicopter functions such as autopilot, guidance and navigation, engine and vehicle control, onboard maintenance, radio communications, and radio navigation. Its modular design provides flexibility for adding new mission functionality, weight savings, lower ownership cost, and high reliability. Major subsystems of the suite include a central panel display, flight control display, automatic flight control, health and usage monitoring, navigation, and centralized radio control systems.
The central panel display system comprises the vehicle and engine management display (VEMD) for single-engine helicopters, and on twin-engine aircraft it is used in conjunction with the caution and advisory display (CAD). The VEMD comprises two active-matrix liquid-crystal displays. It replaces up to a dozen conventional indicators and allows real-time monitoring of both vehicle and engine parameters. The CAD uses a single active-matrix liquid-crystal display and, in conjunction with the VEMD, manages all fuel functions and warnings. It also operates as a backup for main engine parameters in case of VEMD failure.
The flight control display system features two high-resolution multifunction color liquid-crystal displays - the SMD45H (4 x 5 in) and the SMD68 (6 x 8 in). These "smart" displays show both primary flight and navigation information. For specific mission functions such as forward-looking infrared, map generator, and weather radar, the video functions in these smart displays allow this information to be shown using control units on the SMD45H or the SMD68CVN.
Developed and manufactured by SFIM Industries, the automatic flight control system for the Meghas avionics suite consists of highly integrated autopilot modules, high-reliability smart series actuators, trim actuators, single-axis fiber-optic gyros, and an attitude and heading reference system. The attitude piloting reference system integrates three fiber-optic gyros and three miniature accelerometers to provide the autopilot with attitude, rate, and acceleration information in pitch, roll, and yaw.
Frank Bokulich
Aerospace Engineering May 2000
