Aerospace Hydraulic GSE: Maintenance and Troubleshooting Part 1

Aerospace Hydraulic GSE: Maintenance and Troubleshooting
Part I – Types of Contamination

Aerospace aircraft are serviced and maintained using ground service equipment (GSE), which includes service carts that connect to the aircraft on the ground to support maintenance requirements, repair, or replace components. Aerospace GSE supports many intricate systems with service repair carts equipped with hydraulic test stands, compressors, nitrogen, cooling air, and various components such as hydraulic quick couplings. Hydraulic aircraft GSE must be properly maintained according to the OEM operations manual to provide trouble-free service and to prevent catastrophic and costly problems.

Aircraft Hydraulic GSE and the Need for Preventive Maintenance

Maintaining aerospace GSE extends equipment life, reduces the frequency of unscheduled maintenance, and reduces overall lifecycle costs. Hydraulic GSE equipment that interfaces with the aircraft could contaminate and damage sensitive aircraft hydraulic components if not properly maintained. Checking for hose and seal integrity, checking fluid levels, checking for leaks, and preventing contamination are some of the tasks performed during regular maintenance of hydraulic GSE equipment.

Many aircraft GSE systems include hydraulics such as:

• Hydraulic Power Units
• Reservoir Service Units (Engine Oil and Hydraulic Oil)
• Hydraulic Jacks
• Hydraulic Test Units
• Towbars with Hydraulic Height Adjustment
• Hydraulic Cranes
• Hydraulic Maintenance Platforms
• Ground Test Units of Emergency Power Systems
• Hydraulic Wheel and Brake Dollies
• Hydraulic Tire Bead Breakers

Preventing Contamination in Hydraulic GSE Is Critical

Preventing contamination should be the foundation of any preventive maintenance plan for hydraulic GSE. In-depth training for all personnel involved is a mandatory part of any contamination prevention program and can be performed by the equipment manufacturer, the School of Engineering, or the Fluid Power Training Institute. All hydraulic GSE equipment should have a baseline fluid sample with testing performed from an independent laboratory or with a contamination monitor.

Fluid testing should be performed at specific intervals along with regular filter replacement to help prevent contamination in hydraulic GSE. Not all systems interface with the aircraft; closed systems still require inspection and maintenance, such as checking for fluid leaks, verifying fluid levels, and obtaining fluid analysis at predetermined frequencies, unless troubleshooting is required.

Contamination Problems in Hydraulic GSE Fluid

When aircraft GSE experiences hydraulic fluid contamination, it is either from one of four major categories:

• Particles, solid foreign material in the fluid
• Water, free water, or in a solution
• Chemical, from a foreign source, or fluid deterioration
• Air, either entrained or dissolved

Particles

Particle contamination in hydraulic fluid can cause accelerated system wear or complete component failure. Foreign particles can cause abrasive wear on moving components and deteriorate surfaces. Solid particles can clog systems with tight operating clearances and cause unintended equipment shutdowns.

Water

Moisture can cause chemical reactions with hydraulic fluid, leading to performance interference and increased system wear. Water contamination of hydraulic fluids can cause galvanic action, promoting rust and corrosion. This corrosive action leads to surface degradation and fatigue.

Chemical

There are many potential causes of chemical reactions in hydraulic systems, including mixing up hoses and introducing incompatible fluids, chemical reactions with fluids and components, thermal damage caused by excessive heat, deterioration from additives, excessive mechanical shear, breakdown of fluid additives, or variations in viscosity.

Air

Air contamination of hydraulic GSE equipment can produce excessive heat due to pressure changes that compress the air, causing premature wear and decreased operating efficiency. Air contamination also causes oxidation of metal parts, which increases noise levels, operating temperatures, and reduces transmitted power.

These are some of the various methods of contamination that can occur in hydraulic fluid systems in aerospace hydraulic ground service equipment.

Solutions to Prevent Contamination in Hydraulic GSE Equipment

Using the right hydraulic quick couplers for your aircraft hydraulic GSE equipment is critical to prevent contamination. Stucchi is a leading supplier of hydraulic solutions and quick couplings designed for a variety of challenging, heavy-duty applications. Our quick couplings for aerospace GSE include threaded couplings, flat face quick disconnect (QD), and multi-coupling plates. Our hydraulic specialists help you choose the best quick couplers for your hydraulic GSE equipment, as we customize your solutions to meet your specifications with optimal performance.

Stucchi’s design of the flat face quick coupler set the ISO 16028 standard, as a leader in delivering leak-free quick connect solutions. Our flat-face quick couplers eliminate contamination in hydraulic circuits, featuring a no-spill design that prevents fluid loss during both quick connect and quick disconnect operations. Threaded, flat-face quick couplers by Stucchi withstand heavy-duty, pressurized applications with a thread-to-connect design that prevents unwanted disconnection.

Multi-coupling plates prevent cross-connection and chemical fluid contamination, offering easy and reliable quick connect and quick release of multiple lines simultaneously. We offer multi-coupling plates to support the same or different size couplers and the same or different media, such as hydraulic fluid, electrical, or pneumatic lines.

Learn more about preventing contamination with a hydraulic system GSE troubleshooting checklist found in Aerospace Hydraulic GSE: Maintenance and Troubleshooting Part II.

Stucchi is a recognized industry leader in providing hydraulic solutions to many industries, including heavy-duty and challenging configurations. We offer a wide selection of hydraulic quick couplers and multi-coupling plates to improve efficiency, safety, and prevent leaks and contamination. Contact us to learn more about our hydraulic quick couplers for aerospace hydraulic GSE equipment.