Hydraulic Servicing Trolley 200D, two aircraft, one ground unit.

Why the HST 200D matters

The Hydraulic Service Trolley (HST 200D) is suitable for a wide range of fighter aircraft, military transport aircraft, and helicopters used in the Indian Air Force. It is used for actuation of the aircraft hydraulic system through supplied pressurized hydraulic oil from the trolley to the aircraft, comprising a pressurized reservoir with filtered and de-aerated fluid at the flow and pressure characteristics required for testing. The trolley is mainly used for the Sukhoi Su-30MKI, MiG-29, MiG-21, Mirage 2000, and HAL Tejas.

Sub-systems

The hydraulic service trolley consists of the following sub-systems:

• Mechanical structure and its steering system — the trailer chassis, wheels, and Ackerman steering mechanism.
• Prime mover and its accessories — the onboard power source and supporting equipment.
• Twin hydraulic system — two independent delivery and return circuits (System-I and System-II).
• Vacuum system — de-hydration and de-gassing of the hydraulic circuit.

Main hydraulic system

The HST 200D delivers continuous, filtered, high-pressure hydraulic oil supply to two independent aircraft systems. The flow rate is 100 litres per minute (LPM) per system at an operating pressure of 300 bar, with supply pressure exceeding 3,500 psi at the H.P. outlet (3/8″ BSP hose connection). The system is compatible with OM-15, DTD-585, and Superclean MIL-H-5606 mineral-base hydraulic oils, and operates across a temperature range of −5°C to 50°C.

Vacuum system & fluid temperature control

A dedicated vacuum system provides de-hydration and de-gassing of the hydraulic circuit, removing trapped air and moisture to maintain fluid cleanliness. The trolley also includes a hydraulic-fluid high-temperature phenomenon control device to guard fluid condition during extended servicing operations.

Structure, steering & mobility

The HST 200D rides on 4 wheels (2 front, 2 rear) with an Ackerman steering mechanism and leaf-spring suspension at front and rear. Overall dimensions are 2300 mm (L) × 1100 mm (W) × 1200 mm (H), with a 140-litre fuel tank and a rear axle weight of 1100 kg. The unit is towable at up to 10 km/h for repositioning around the flight line.

Applications of the HST 200D

The Hydraulic Service Trolley (HST 200D) is an essential ground support tool for Indian Air Force line maintenance:

• Fighter aircraft servicing: Sukhoi Su-30MKI, MiG-29, MiG-21, Mirage 2000, and HAL Tejas.
• Military transport aircraft & helicopters: hydraulic servicing across the wider Indian Air Force fleet.
• Dual-aircraft ground servicing: two independent hydraulic systems serviced simultaneously via System-I and System-II.
• Fluid condition management: filtration, de-hydration, de-gassing, and high-temperature control for clean, dry hydraulic oil.

Why choose the HST 200D?

• Dual aircraft servicing — supports two aircraft systems simultaneously via independent delivery and return lines.
• Panel-controlled precision — delivery pressure and flow steplessly controlled, with full instrumentation.
• Flexible tank configuration — trolley tank isolated, aircraft tank used, or both tanks in circuit.
• Vacuum de-aeration — de-hydration and de-gassing keep hydraulic fluid clean and moisture-free.
• Field-mobile — Ackerman-steered, leaf-sprung chassis towable at up to 10 km/h.

Delivery and support

Neometrix backs the HST 200D as manufacturer and supplier with installation, commissioning, operator training, preventive maintenance, spares, and on-site service support — for customers across India and export markets in defence and aerospace.

Conclusion

The Hydraulic Servicing Trolley (HST 200D) delivers dependable, dual-aircraft hydraulic ground support for the Indian Air Force fighter, transport, and helicopter fleets — combining filtered high-pressure delivery, vacuum de-aeration, and panel-level control in a single towable unit.