Testing and Charging Test Rig for Main and Nose Landing Gears, charging to 9800 psig without electrical power.

1. Introduction

The T-A1314 Testing and Charging Test Rig is a precision-engineered, high-performance, self-contained hydraulic and pneumatic test system specifically developed for aircraft main and nose landing gear assemblies. It is designed to execute a full spectrum of testing and maintenance operations — including shock absorber testing, nitrogen charging, hydraulic charging, bleeding, electrical continuity checks, leak detection, and steering/self-centering functionality assessment — all in a compact and mobile skid-mounted unit.

Built for rugged operational environments, the test rig integrates high-pressure hydraulic systems, nitrogen (N2) delivery circuits, and air-driven booster pump technology, eliminating the need for electrical power input. The system is ideal for ground servicing applications in aerospace maintenance, repair, and overhaul (MRO) facilities, as well as defence establishments and aircraft OEMs.

2. Target Landing Gear Units

The rig is designed and calibrated for use with the following aircraft landing gear models (customizable for any):

• Main Landing Gear Assemblies: 06R4A100000010B / 06R4A100000020B, 06T4A100000010C / 06T4A100000020C.
• Nose Landing Gear Assemblies: 06R4B100000000B, 06T4B100000000D.

3. Functional Capabilities

The test rig enables the following critical procedures for both main and nose landing gear systems:

• Shock absorber filling and levelling
• Nitrogen (N2) charging via regulated circuit
• Hydraulic charging using booster or hand pump
• Shock absorber testing under controlled pressures
• Bleeding of hydraulic systems
• Self-centering and steering performance testing
• Electrical continuity and function check (auxiliary)
• Leak testing and pressure-drop monitoring

Each procedure is performed with dedicated valves, indicators, and pressure control mechanisms, ensuring repeatability, accuracy, and operator safety.

4. System Construction and Design

Structural Framework

• Type: Mobile enclosed skid with four wheels (locking-enabled)
• Frame Material: High-grade MS steel base with reinforced canopy
• Mounting Features: Provision for secure placement of N2 cylinders and hand pump

Dimensions

• Without wheels and cylinder fixture: 800 × 600 × 1535 mm (W × D × H)
• With wheels only: 800 × 600 × 1642 mm (W × D × H)
• With wheels & cylinder mounting fixture: 800 × 900 (max) × 1642 mm (W × D × H)

5. User Interface Panel

The front-facing user panel provides all controls and feedback for system operation.

Instruments and Controls

• Pressure Gauges: Air pressure gauge (100 mm dial), range 0–200 psi
• Digital Pressure Indicators (3 units): Line 1 – Hand Pump Pressure (19.1); Line 2 – Main Line High-Pressure (19.2); Line 3 – Main Line Low-Pressure (19.3)
• Control Valves: ON/OFF valve for drive air/N2; pressure regulator for booster pump (air supply side); 4 needle control valves (code 6.0, 13.0, 21.1, 21.2)
• Isolation Valves: Hand pump line (24.1), main line high range (24.2), main line low range (24.3)
• Bulkhead Ports: 4 × 1/2″ BSPP Male (hydraulic); 1 × 1/4″ BSPP Female (N2 line); 4 sampling ports for calibration/diagnosis

6. Hydraulic System

Hydraulic Booster Pump (Air Hydro Pump / Intensifier)

• Type: Air-driven
• Max Output Pressure: 9800 psig (676 bar)
• Air Supply Requirement: Pressure 60–80 psig (optimum 105 psig at rig inlet); flow rate minimum 2.83 NM³/min (clean, dry air)
• Drive Air Port: 1/2″ BSPP (Male), rear-mounted

Hand Pump

• Dual-stroke design: Low-pressure stroke 49 cc (up to 30 bar); high-pressure stroke 2.8 cc (up to 700 bar)
• Integrated with 6-litre oil reservoir
• Output: Up to 10150 psig

Reservoir

• Material: Stainless steel (2–3 mm thickness)
• Capacity: 50 litres

7. Nitrogen Charging System

• N2 Inlet Port: 1/4″ tube OD (rear-mounted)
• N2 Outlet Port: 1/4″ BSPP (Female)
• Operating Pressure: Up to 3500 psig
• Regulator: High-pressure HAL-compatible N2 regulator with inlet/outlet gauges
• Safety Clamp Fixture: For N2 cylinder support

8. Filters and Cleanliness Control

• 2 × hydraulic filters (2 micron, 6000 psi, clogging indicator)
• 1 × air filter (5 micron, installed on air supply line)
• Inline suction strainer (125 micron)

9. Safety Features

• Solenoid Interlock Valve (24 VDC): Automatically stops drive air to the booster pump if system pressure exceeds 6000 psi
• Pressure Isolation Valves: Protect pressure transmitters and allow sensor maintenance without depressurizing the entire system
• Overpressure Safety Procedures: SOP integrated with automatic shutoff protocols and manual emergency release options (e.g., dump valve 6.0)

10. Calibration & Monitoring

• Pressure Transducers: 0–500 psi (0.25% accuracy, 4–20 mA); 0–6000 psi (2 units, 0.25% accuracy, 4–20 mA)
• Digital Indicators: 3.5-digit and 4-digit display models
• Calibration Ports: 4 × Minimess diagnostic couplings (6000 psi)

11. Standard Operating Procedures (S.O.P)

Modes supported:

• Hydraulic charging (main booster line)
• Pressure proof / leak testing (main booster or hand pump line)
• Manual charging (hand pump line)
• N2 line charging or leak testing

Each procedure includes detailed valve operations, safety isolation, test connections, and pressure monitoring via digital indicators.

12. Maintenance Schedule

13. Troubleshooting Guide

The manual includes a step-by-step fault identification and resolution chart covering common issues such as:

• No pressure on display
• Booster running with no pressure output
• Pressure build-up despite booster inactivity
• Incorrect valve positions during test sequences

Conclusion

The Testing and Charging Test Rig represents a state-of-the-art solution for the maintenance and testing of aerospace landing gear systems. With its air-powered operation, precision pressure control, comprehensive safety features, and user-centric design, this test rig is ideal for aviation MRO workshops, OEMs, and defence ground support operations that demand high reliability, safety, and operational flexibility.