Ultrasonic Critical Contact Testing
Precision Contact UT for Thin-Wall Machined and Flight-Critical Parts. Mitchell Laboratories specializes in high-sensitivity ultrasonic contact inspection for machined aerospace components requiring multi-mode wave testing, tight tolerances, and procedural precision.
What Is Ultrasonic Critical Contact Testing?
Ultrasonic Critical Contact Testing is a specialized non-destructive testing (NDT) method that uses high-frequency sound waves, introduced via direct contact between a transducer and the test surface, to detect internal or surface-breaking flaws in thin-wall, machined, or flight-critical components.
Advantages of Ultrasonic Critical Contact Testing
- Designed for Thin-Wall & Machined Parts: Ideal for aerospace-grade components requiring internal flaw detection in delicate geometries and materials.
- Multi-Mode Ultrasonic Inspection: Uses five or more ultrasonic wave modes—longitudinal, shear, and angle-beam—depending on material and geometry.
- Dedicated Inspection Area: A segregated, purpose-built lab ensures focus, accuracy, and a controlled environment for prime-approved techniques.
- Highly Trained Technicians: Inspections are performed by experienced Level 2 personnel under procedures developed and approved by certified Level 3 UT experts.
- Repeatable, Prime-Approved Techniques: Techniques are refined to meet OEM and prime contractor standards, ensuring consistent, auditable inspection performance.
- Custom Transducers, Wedges, and Standards: Technicians utilize a full inventory of program-specific transducers, reference blocks, and angle-beam wedges.
- Full Traceability and Documentation: Results are fully traceable and available in print or Windows-compatible digital formats, ensuring compliance with aerospace quality standards.
Limitations of Ultrasonic Critical Contact Testing
While highly effective for aerospace-grade inspection, this method has some limitations:
Requires direct contact, making access challenging for complex or obstructed geometries.
Basic Principles of Ultrasonic Critical Contact Testing
Ultrasonic critical contact testing is a non-destructive method that transmits high-frequency sound waves into a component through a transducer in direct contact with its surface. Reflected signals from internal flaws, boundaries, or material changes are analyzed to identify subsurface defects. Depending on geometry, Mitchell Laboratories uses 3 wave modes – Longitudinal-wave, Shear-wave & Surface-wave. (Angle-beam can include angled L-wave so technically not a wave mode) We often perform 2 Longitudinal-wave inspections (depending on material thicknesses) and 2 Shear-wave inspections (different angles for different thicknesses), and Surface-wave inspection.
At Mitchell Laboratories:
- Multiple wave modes, including Longitudinal-wave, Shear-wave & Surface-wave.
- Technicians apply custom wedges and reference standards based on the geometry and part type.
- All procedures are developed by Level 3 UT personnel and executed by certified Level 2 technicians.
- Emphasis is placed on repeatability, signal interpretation, and surface coupling quality to ensure inspection reliability
Common Applications
Thin-Wall Turbine Components
Precision-Machined Brackets
Contoured Engine Parts
Flight-Critical Titanium Castings
Bonded or Composite Assemblies
Quality Assurance & Compliance
- ISO 9001 & AS9100D Certified
Meets rigorous aerospace and defense quality standards. - ITAR Registered
Fully compliant with U.S. government export controls for defense-related inspections. - NADCAP Accreditation
Nadcap-approved processes in place for special-process ultrasonic inspection. - 100% Dimensional Traceability
All results are traceable to part, batch, inspection procedure, and technician. - In-House Reference Standards
Includes program-specific blocks, wedges, and transducers required for precise inspection. - Certified Personnel
Work performed by SNT-TC-1A and NAS 410 trained Level 2 inspectors under Level 3 oversight. - Continual Improvement Program
Internal reviews and customer-driven refinements enhance reliability and inspection quality.
Frequently Asked Questions
Typically thin-wall, finished machined parts—often flight-critical components—where immersion is not feasible or allowed.
Many inspections require five or more wave modes, including longitudinal, shear, and angle-beam.
Yes. Techniques are written and approved by UT Level 3s and comply with major prime contractor specifications.
We maintain a full inventory of custom transducers, wedges, and program-specific reference blocks.
Lead times are quoted on a job-by-job basis to ensure accuracy, and we’re happy to accommodate emergency or rush requests. Backed by decades of refining our expedited process under strict deadlines, we minimize turnaround without ever sacrificing quality, returning your parts quickly and reliably.