NP-72MV

Pressure generation by the NP-72MV pump

The main function of the NP-72MV is to create hydraulic pressure for flight-control, landing-gear, braking and wing-mechanization systems, depending on the aircraft type. The pump is not just a transfer unit for fluid circulation. It is a high-pressure hydraulic power source that feeds the system with variable delivery. When hydraulic demand is present, the pump increases delivery. When system pressure reaches the upper working range, its internal regulator reduces output and protects the system from unnecessary loading. This makes the pump suitable for continuous work in the main hydraulic network.

Variable-displacement design of NP-72MV

The NP-72MV is built as an axial-piston pump with a variable delivery mechanism. The pump’s internal piston group and regulator assembly adjust the amount of hydraulic fluid supplied to the system. This allows the unit to respond to pressure changes instead of constantly delivering maximum flow. In normal operation, the pump charges the hydraulic system and then reduces delivery when the pressure reaches the required level. This design lowers heating, reduces load on the drive, and keeps the hydraulic system within its intended pressure range.

NP-72MV installation on aircraft engines

The NP-72MV is mounted on the engine accessory gearbox, for example on aircraft using D-36-type engine installations, depending on aircraft configuration. The pump drive shaft is connected to the gearbox spline shaft, which transfers rotation from the engine to the pump rotating group. Because of this installation method, correct spline condition, flange fit, sealing, alignment and rotation are important during maintenance. If the pump is installed incorrectly or the drive interface is damaged, the aircraft hydraulic system may lose pressure or the pump may suffer mechanical wear.

NP-72MV in An-72, An-74 and Yak-42 systems

The NP-72MV is associated with aircraft such as An-72, An-74 and Yak-42, where it works in the main hydraulic power system. On these aircraft, hydraulic pressure is used by landing gear, wing mechanization, brake circuits, steering or flight-control actuators depending on the system layout. The pump works with hydraulic reservoirs, shut-off valves, check valves, pressure regulators, relief valves and accumulators. For troubleshooting, it is important to look at the whole pressure-source circuit, not only the pump. A pressure issue may come from the pump, suction line, regulator, relief valve, reservoir pressure, or downstream leakage.

Hydraulic equipment working with NP-72MV

In the aircraft hydraulic system, the NP-72MV may work together with engine fire shut-off valves on the suction line, hydraulic reservoirs, check valve blocks, safety valves and hydraulic accumulators. A shut-off valve can stop fluid supply to the pump in an engine fire condition. Check valves prevent reverse flow when the engine is stopped or when another pressure source is operating. Relief valves protect the system if pressure rises beyond the permitted limit. Hydraulic accumulators reduce pulsations and store pressure for short-term demand. These units form the working environment around the pump.

Service inspection and supply of NP-72MV

The NP-72MV is an aircraft component subject to strict technical control. When ordering or replacing the pump, the full designation, aircraft type, engine installation, documentation status and remaining life must be checked. A unit may be supplied as new, first-category storage stock, repaired, overhauled or serviceable with documents. Before installation, maintenance personnel normally inspect the body, drive shaft, flange, ports, regulator area, sealing surfaces, storage condition and passport records. Bench testing should confirm pressure, delivery, regulator response, leakage and operation under specified conditions.