AK-50T1 Series 3

Mechanical drive of the AK-50T1 Series 3 compressor

The AK-50T1 Series 3 is an engine-driven unit. On helicopter applications it is mounted on the accessory drive section of the main gearbox, such as VR-8A, VR-14 or VR-24 depending on the helicopter type. Rotation is transmitted to the compressor shaft through the drive connection, and this mechanical drive makes the compressor operate while the aircraft powerplant and gearbox system are running. Because of this installation, the compressor must be checked not only as a pneumatic unit, but also as a mechanically driven accessory connected to the gearbox system.

AK-50T1 Series 3 construction and compression cycle

The AK-50T1 Series 3 is a crank-type, two-stage, single-cylinder, air-cooled compressor. Its construction includes a crankcase, eccentric shaft, connecting rod, piston, first-stage and second-stage cylinders, and an air intake filter. Air is drawn in, compressed in stages, and discharged into the pneumatic line. This staged compression allows the unit to reach the required system pressure while keeping the compressor compact enough for aircraft installation. The compressor works under high mechanical load, so shaft speed, cylinder temperature, air intake condition and lubrication all affect serviceability.

Lubrication of the AK-50T1 Series 3 from the gearbox oil system

The compressor is lubricated by aircraft oil supplied under pressure. In helicopter installations, lubrication is commonly connected with the main gearbox oil system. Oil is fed to the rubbing parts of the compressor and removes part of the heat from the working assembly. Correct oil pressure and temperature are important for stable operation. If oil supply is poor, contaminated or overheated, the compressor may suffer increased wear, heating, loss of efficiency or damage to internal parts. For maintenance, the compressor should be checked together with the oil supply path and gearbox service condition.

Compressed air path after the AK-50T1 Series 3

After leaving the AK-50T1 Series 3, compressed air normally passes through cleaning and control elements before reaching the onboard storage bottles. The line may include a filter-separator such as 5565-10, which removes moisture and oil residue. The AD-50 pressure regulator controls system charging: when pressure reaches the upper limit, it unloads the compressor and releases air to atmosphere; when pressure drops, it directs air back into the system. Check valves such as 636100M or 998A4 prevent stored compressed air from flowing back toward the compressor.

AK-50T1 Series 3 with onboard air bottles and consumers

The compressed air produced by the AK-50T1 Series 3 is stored in onboard air bottles or, on some helicopter configurations, in sealed cavities of the main landing gear struts. From there, air is supplied to pneumatic consumers. Typical users include wheel brake systems through a pressure-reducing valve such as PU-7, as well as other aircraft systems depending on configuration. The compressor itself does not operate the brakes or other consumers directly. It fills and maintains the pneumatic supply that those consumers use when commanded by the aircraft control system.

Compatibility and non-interchangeability of AK-50T1 Series 3

The AK-50T1 Series 3 should be identified carefully by full designation and series. It is not interchangeable with AK-50T, AK-50A, AK-50A1, AK-50M or AK-50M1. These compressors may look similar or belong to the same family, but differences in design, drive, installation, operating parameters or aircraft applicability can make substitution unacceptable. For ordering or replacement, the exact designation AK-50T1 Series 3, the required documentation and the target aircraft type should be confirmed before shipment.

Supply, inspection and documentation for AK-50T1 Series 3

For aircraft use, the AK-50T1 Series 3 should be supplied with passport documentation and checked according to the applicable maintenance requirements. Before installation, the unit should be inspected for shaft condition, drive interface, air intake filter, housing condition, oil connection points, signs of overheating, corrosion, storage damage and contamination. Since the compressor has assigned resource and service life limits, documentation matters as much as the physical condition of the part. A unit from storage or after repair should have records confirming its status and suitability for installation.

Confirmed installation context includes Mi-8 / Mi-17 family helicopters. Exact applicability of the individual execution must be checked against the illustrated parts catalogue and aircraft documentation.