458M Series 2

Function of the 458M Series 2 gyro sensor

The main function of the 458M Series 2 gyro sensor is to determine the spatial position of an aircraft relative to the true horizon. It measures roll and pitch and transmits these values electrically through built-in selsyn transmitters. The receiving equipment then displays or uses these signals for flight control and stabilization tasks. The sensor is installed remotely from the cockpit indicator, which allows the attitude reference unit to be mounted in a protected equipment bay while the pilot receives indication on the instrument panel.

458M Series 2 in the AGD-1 system

The 458M Series 2 gyro sensor was originally used as the vertical reference sensor for the AGD-1 remote attitude indicator. In this configuration, the sensor forms the attitude signal, while cockpit indicators display aircraft roll and pitch to the crew. The system architecture allows one gyro sensor to serve remote indication and, depending on aircraft wiring, related automatic flight control circuits. For this reason, the unit is often referred to as the AGD-1 attitude indicator gyro sensor.

Measurement range and operating features

The 458M Series 2 sensor measures roll and pitch angles over a full 360-degree range, except for the structural blind zone around high pitch angles where the gimbal axes approach alignment. The source context indicates a blind zone in the 85°–95° pitch area during climb or dive attitudes. The unit is intended to provide stable signals during normal flight modes and permitted aerobatic attitudes. Accuracy is maintained through gyro correction systems, including pendulum correction with defined precession rates.

458M, 458MKS and 458MB modifications

The 458 family includes several related modifications. The 458M Series 2 is the basic serial gyro sensor version. The 458MKS Series 2 modification performs the same main attitude signal function and additionally generates discrete electrical commands when critical roll angles are reached. The source context also mentions the 458MB Series 2 specialized modification. Because the modifications can differ by output signals, wiring and system role, the exact designation and aircraft installation must be checked before replacement.

Aircraft application and maintenance of 458M Series 2

The 458M Series 2 gyro sensor is used on aircraft fitted with AGD-1 / AGD-1S remote attitude indicator systems. Source context indicates application on L-39, L-29, Yak-18T, An-24, An-26, An-12, Il-18, Tu-134 and some Mil and Kamov helicopter configurations, including older Mi-8 stabilization systems. For procurement, the buyer should confirm the exact aircraft system, condition, passport availability, repair certificate and test status. The unit should be supplied and installed according to aviation maintenance documentation.