Aviation Tap Hammer Testing - Practical Training to Assess Serviceability of Composite Material

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Sofema Online (SOL) www.sofemaonline.com considers the fundamentals to provide a practical hands-on session to build process confidence and develop competence.


In this practical hands-on session, we will focus on assessing the serviceability of composite materials using an aviation composite tap testing hammer. The tap testing method allows us to detect and evaluate such damage by analyzing the acoustic response of the composite material. Let's dive into the step-by-step procedure.

Materials Required

>> Aviation composite tap testing hammer or coin tap tool.
>> Composite samples with known defects (to provide a benchmark for defect sounds).

o Choose a range of composite material specimens, including both previously damaged and undamaged samples.
o Ensure the specimens are of the same type and thickness, allowing for accurate comparisons.

>> Safety glasses and gloves.
>> Documentation for recording observations.


>> Prepare a selection of composite material samples, both in good condition and with a variety of intentionally induced defects (e.g., delamination, porosity, inclusions, or dry areas).
>> Ensure safety equipment is available for all participants.
>> Place a soft rubber or foam pad on the workbench surface to provide a consistent base for testing.
>> Ensure you are working in a well-ventilated area or a designated workshop.


Maximum Group Size 6 persons per session following the referenced steps.

>> Toolbox Talk to Review the basics of tap testing.

o Its purpose
o How it works
o What types of defects it can and cannot detect
o Discuss the limitations of tap testing, and where other nondestructive testing methods like ultrasonic or thermography might be appropriate.


>> Demonstrate the correct method for tap testing.
>> Hold the hammer by the handle, aligning the striking head perpendicularly to the surface of the specimen.
>> Emphasize that it requires a quiet environment to hear the difference in sound.
>> Show the correct way to hold the hammer and perform the tap test.

Defect Recognition

>> Tap on good and defective areas of the samples
>> Tap on undamaged composite material specimens with the hammer and observe the sound produced.
>> Gently tap the specimen at regular intervals while maintaining consistent force.

o Pay attention to the sound characteristics, such as pitch, tone, and resonance.
o Practice identifying the different sounds that result from tapping on intact material versus defective material.
o Identify any differences in sound characteristics, such as dullness, dead spots, or changes in resonance

Note: The sound from an intact composite structure is sharp, while a dull thud indicates a problem, such as delamination or disbanding.

Hands-On Practice

Each participant to practice tap testing on the samples.

>> Provide Guidance on how to interpret the different sounds.
>> They should note their observations on the documentation.


Record all observations including the type of specimen, tap test results, and any visible damage.

>> Use a scale or rating system to quantify the severity of damage, if applicable.
>> Compare the tap test results with the known condition of the specimen.

Discussion and Feedback

Following individual practice for all participants, gather the group for a discussion.

>> Compare notes on what each participant observed.

o This can help to clarify any confusion and further reinforce learning.
o Sharing your observations and insights.
o Draw conclusions about the effectiveness of the tap testing method in assessing composite material serviceability.

>> Wrap up the session by answering any questions participants may have and summarize the key points of the session.

Next Steps

Sofema Aviation Services (www.sassofia.com) offers the following 2 day course - Composite Material TAP Testing for Aviation Inspectors. Please email team@sassofia.com for further information.

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