Testing that Reaches the World

Precision • Qualification • Airworthiness Confidence

For more than 33 years, Clark Testing has partnered with aerospace OEMs, Tier 1 suppliers, MRO facilities, and defense contractors to verify that critical parts, subsystems, and full assemblies perform safely and reliably in the air and on the ground. Our ISO/IEC 17025–accredited laboratories deliver structural, mechanical, environmental, materials, hydraulic, and analytical testing aligned with FAA, EASA, MIL-STD, RTCA/DO-160, AS9100 quality system interfaces, and customer‑specific specifications. Whether you need qualification of a new design, lot acceptance for production hardware, failure investigation, or lifecycle condition monitoring, Clark provides the trusted data packages needed for certification, compliance, and mission success.

Why Clark for Aerospace Testing?

• Broad Capability Under One Roof – Structural, hydraulic, environmental, mechanical, materials/analytical, and dynamic testing supported by large‑scale fixtures and high‑capacity power systems.
• Certification‑Ready Data Packages – Procedures documented to recognized aerospace and military standards with full traceability and instrument calibration.
• Scalable Test Fixturing – From coupon‑level materials characterization to full landing gear, flight control, and system‑level functional rigs.
• High Force / High Pressure Infrastructure – Static structural loads to 2,000,000 lb; hydraulic pressures to 30,000 psi; temperature extremes from −346°F to +600°F; altitude simulation to 60,000 ft.
• Experienced Test Engineering Team – Decades of hands‑on aerospace program support, custom rig design, and complex data acquisition.

Core Service Areas

• Landing Gear & Brake System Testing
• Aerospace Hydraulic Component & System Testing
• Aerospace Hydraulic Fluid Analytical Testing
• Aerospace Grease Qualification & Benchmark Testing
• Structural Testing of Aircraft, Rotorcraft & Spacecraft Components
• Environmental, Vibration & Altitude Simulation

Each service can be delivered as a stand‑alone engagement or integrated into a multi‑discipline qualification program.

Landing Gear & Brake System Testing

Landing gear is a flight‑critical system that must reliably absorb impact energy, support taxi and ground loads, function through repeated retract/extend cycles, and integrate with steering and braking subsystems—often across extreme temperature and environmental ranges. Clark Testing provides full‑scale and sub‑scale landing gear test programs that combine structural loading, dynamic impact, environmental exposure, and functional operation.

Landing Gear Types & Configurations Supported

• Fixed and retractable designs
• Nose / main / tailwheel, tricycle, tandem, and multi‑bogie arrangements
• Military, commercial transport, business jet, rotorcraft, and UAV gear sets

Key Landing Gear Elements We Test

• Shock struts / energy absorption assemblies
• Wheels & tires
• Retraction, extension & locking mechanisms
• Steering linkages & actuators
• Brake assemblies (disc, drum, carbon, multiple‑rotor) and associated controls

Representative Landing Gear Test Protocols

1. Limit Drop Tests – Simulate nominal landing impact by dropping the gear or a representative mass from a specified height. Instrumentation captures impact loads, stroke/deflection, energy absorption efficiency, and rebound characteristics.
2. Reserve Energy (Over‑Load / Hard Landing) Drop Tests – Higher drop energy (often 1.5× limit conditions, or per customer spec) to demonstrate margin under severe or off‑nominal landing events.
3. Static Load Tests – Application of calibrated vertical, side, drag, and combined loads representing aircraft weight envelopes, CG excursions, braking forces, and ground reaction factors. Clark structural loading systems provide up to 2,000,000 lb (≈8,896 kN) capacity.
4. Functional Retract / Extend Cycling – Powered actuation to verify timing, sequence integrity, mechanical locking, indication, and redundancy. High‑cycle endurance and fault‑insertion options available. Conducted in our 50,000 sq ft mechanical lab with full hydraulic and electrical support services.
5. Brake Performance & Wear Testing – Dynamometer‑based brake torque, energy absorption, fade, cooling, and wear‑debris characterization across simulated taxi, rejected takeoff (RTO), and landing duty cycles.
6. Environmental Exposure – Integrated temperature, altitude, salt fog, humidity, sand & dust, and fluid contamination conditioning with post‑exposure functional checks.

Environmental Simulation Highlights

• Temperature & Thermal Shock: High/low conditioning and thermal gradients to support cold‑soak or hot‑day scenarios.
• Altitude / Low Pressure: Chamber simulation to 60,000 ft equivalent for pressure‑sensitive components (struts, actuators, seals, position sensors).
• Sand & Dust Intrusion: Blowing media exposure to evaluate seal performance and mechanism function in austere environments.
• Vibration & Shock: Electrodynamic (high‑frequency) and hydraulic (large‑stroke/low‑frequency) shake tables replicate transport, taxi, and runway roughness spectra; modal survey options available.

Aerospace Hydraulic Component & System Testing

Hydraulic power is foundational to modern aircraft—controlling flight surfaces, landing gear, brakes, cargo doors, thrust reversers, and more. Clark Testing operates dedicated aerospace hydraulic test bays capable of component characterization, endurance cycling, proof/burst pressure qualification, and fully integrated system rigs.

Facility Capabilities

• Hydraulic power supplies >140 GPM aggregate capacity
• Pressure control to 30,000 psi
• Temperature conditioning from −346°F (−210°C) to +600°F (+316°C)
• Closed‑loop control with high‑accuracy transducers for pressure, flow, temperature, and position
• Data acquisition synchronized across multiple channels for dynamic response analysis

Typical Hydraulic Tests

• Pressure Proof / Burst – Demonstrate structural integrity and margin.
• Dynamic Pressure & Flow Mapping – Characterize performance across operating envelope.
• Temperature/Vicosity Effects – Validate operation through cold‑soak start‑up, hot‑day, and transient thermal swings.
• Leakage, Seal, & Drift Assessments – Measure internal and external leakage rates over time and cycle count.
• Component Qualification – Cylinders/actuators, servo & proportional valves, accumulators, pumps, manifolds, hoses, fittings, reservoirs, quick disconnects.
• System‑Level Functional Rigs – Integrated loop testing that simulates flight control actuation, landing gear deploy/retract, brake control, and emergency backup functions; includes cyclical aging and endurance programs.

Aerospace Hydraulic Fluid Analytical Testing

Maintaining hydraulic fluid integrity is essential to system responsiveness, service life, fire safety, and corrosion control. Clark Testing’s analytical laboratory supports qualification, conformity, compatibility, and in‑service condition monitoring for both military and commercial aviation fluids. Testing is executed within our ISO/IEC 17025 quality framework using ASTM, ISO, SAE, and MIL‑spec methods.

Program Applications

• New formulation qualification
• Incoming lot certification & supplier validation
• Periodic fleet condition monitoring / oil analysis programs
• Contamination troubleshooting & root‑cause analysis
• Material compatibility (seals, elastomers, coatings, metals)

Representative Aerospace Hydraulic Fluid Specifications

• MIL‑PRF‑5606 – Petroleum‑based hydraulic fluid for aircraft & missile systems.
• MIL‑PRF‑83282 – Fire‑resistant hydraulic fluid (synthetic hydrocarbon base); wide temperature range.
• MIL‑PRF‑87257 – Advanced synthetic, fire‑resistant fluid with improved low‑temperature viscosity.
• MIL‑H‑46170 – Rust‑inhibited petroleum hydraulic fluid.
• DEF STAN 91‑48 / NATO H‑515 – Allied military standards for fire‑resistant fluids.
• Commercial Phosphate Ester Families (e.g., Skydrol® LD‑4, 5, PE‑5) – Widely used in transport aircraft systems.

Common Test Methods (Partial Listing)

Physical & Chemical Properties

• ASTM D445 – Kinematic viscosity
• ASTM D664 / D974 – Acid & neutralization numbers
• ASTM D892 – Foaming characteristics
• ASTM D4176 – Visual clarity, sediment & free water
• ASTM D2272 – RPVOT oxidation stability
• ASTM D4310 – Sludge & corrosion deposits (RPVOT companion)
• ASTM D1744 – Water by Karl Fischer
• ASTM D5185 – ICP elemental analysis (wear metals / contaminants / additives)
• ASTM D665 – Rust prevention
• ASTM D130 – Copper strip corrosion

Cleanliness & Particulate Control

• ISO 4406 / ISO 4407 – Particle count & sizing
• NAS 1638 / SAE AS4059 – Cleanliness classification

Fire & Safety

• SAE ARP5412 / ARP5416 – Fire‑resistance & ignition behavior evaluations

Need a full test matrix? We’ll align methods to your procurement spec, maintenance manual, or OEM acceptance criteria.

Aerospace Grease Qualification & Benchmark Testing

Aerospace greases must lubricate under wide load, speed, and temperature extremes; resist washout, fretting, and corrosion; and remain stable through long dormant periods followed by sudden duty. Clark Testing performs analytical characterization, batch acceptance, and application‑specific mechanical benchmarking for aircraft, rotorcraft, and spaceflight greases.

Key Grease Specifications Supported

• MIL‑PRF‑23827 – General‑purpose aircraft grease; broad low/high temperature window (approx. −73°C to +177°C / −100°F to +350°F range class).*
• MIL‑PRF‑81322 – High‑load, corrosion‑inhibited synthetic hydrocarbon grease for high‑speed & heavily loaded components.
• MIL‑PRF‑32014 – High‑performance, water‑resistant grease formulation specification.
  (*Temperature ranges are formulation dependent; consult individual product data sheets.)

Typical Aerospace Grease Applications

• Actuator bearings & linkages
• Landing gear trunnions & joints
• Engine & accessory drive components
• Helicopter main & tail rotor bearings
• Aircraft wheel bearings
• Spacecraft mechanisms (hinges, slip rings, deployment devices)

What We Do

• Specification conformance & lot acceptance testing
• Rheology / penetration / bleed / volatility characterization
• Low‑ & high‑temperature torque, starting, and running resistance
• Corrosion & wear protection benchmarking across competing products
• Integration with system‑level rigs (e.g., landing gear, brake assemblies) for lubricant performance comparison under load and duty cycle

Structural Testing for Aerospace Components & Assemblies

From coupon development testing to full aircraft substructure qualification, Clark’s Structures Laboratory is engineered for scale, flexibility, and data quality. We support fixed‑wing, rotorcraft, UAV, launch vehicle, and space hardware programs.

Structures Laboratory Infrastructure

• Reinforced structural floor: 90 ft (L) × 30 ft (W) × 10 ft (D) reaction mass with 48‑in on‑center, high‑capacity tension bolt grid (up to 240,000 lb anchor loads per position).
• Modular steel arches, strongbacks, and fixturing for vertical, horizontal, torsional, and combined load application paths.
• Multiple hydraulic power units to 160 GPM feeding high‑force actuators.
• Hydraulic cylinders & actuator sets delivering up to 2,000,000 lb (≈8,896 kN).
• 1,000,000 lb MTS® load frame for high‑throughput structural component programs.

Structural Test Modalities

Static Proof / Ultimate Load – Gradual or stepped load application to design limit and beyond to demonstrate margin, stiffness, and failure modes.
Fatigue / Durability – Constant or variable amplitude cyclic loading to simulate flight hours, mission spectra, or ground duty cycles.
Dynamic / Crash / Impact – Transient loading, drop towers, and hydraulic pulse systems replicate impact and crash conditions.
Vibration & Modal Survey – Electrodynamic shakers (high‑frequency) and large‑stroke hydraulic exciters (low‑frequency / high amplitude) for aero‑transport, launch, and in‑service environments.
Correlation & Model Validation – Test‑to‑analysis correlation for finite element model (FEM) validation and certification support packages.

Environmental Test Support

Environmental stress screening (ESS) and qualification are frequently integrated with our structural and functional programs. Available environmental conditioning includes:

• Thermal cycling & thermal shock
• Temperature extremes (liquid nitrogen & high‑temperature ovens)
• Altitude / vacuum simulation to 60,000 ft equivalent
• Humidity & salt fog
• Sand, dust, and debris exposure
• Fluid susceptibility (Skydrol, fuels, de‑icing fluids, hydraulic fluids)
• Combined environment + functional operation

Data, Reporting & Quality

Every aerospace program at Clark is executed under documented procedures tied to calibrated instrumentation and controlled data acquisition systems. Deliverables can include:

• Detailed test procedures & setup drawings
• Instrumentation & calibration records
• Raw & reduced data files in customer‑specified formats
• Test reports with plots, photos, and engineering commentary
• Nonconformance documentation & corrective action tracking when required

We interface with customer quality systems (AS9100, NADCAP‑aligned requirements, OEM design authority specs) and can host customer or regulatory witness testing.