Boeing 737-500: Loop & Joint Resistance Testing Equipment

Loop and joint resistance testing verifies the electrical continuity and integrity of various aircraft systems. It involves measuring the resistance across electrical connections, bonds, and ground paths to ensure they are within specified limits. This testing helps identify potential issues like loose connections, corrosion, or damaged wiring that could compromise the aircraft's electrical systems and overall safety.

Loop and joint resistance testing is crucial for aircraft safety as it helps prevent electrical faults, electromagnetic interference, and potential lightning strike damage. By ensuring proper electrical bonding and grounding throughout the aircraft, this testing minimizes the risk of electrical fires, system malfunctions, and navigation errors. It also plays a vital role in maintaining the aircraft's lightning protection system, which is essential for safe operations in various weather conditions.

Loop resistance testing works by sending an electrical current through a circuit or wiring loop and measuring the resistance encountered along the path. This test identifies the quality of the electrical connections within the loop, ensuring that there are no excessive resistance points caused by factors like corrosion, loose connections, or damaged wires. Technicians use specialized equipment, such as the ExLRT and the AX 6000, to conduct these measurements and verify that the wiring provides a low-resistance pathway for electrical signals, ensuring safe and efficient operation in aircraft systems.

Joint resistance testing is conducted by measuring the electrical resistance across connections or joints within an aircraft’s wiring system to ensure strong, low-resistance connections. Advanced tools, such as the ExLRT and the AX 6000, are used to send a current through the joint and evaluate the resistance levels. High resistance at these points may indicate poor connections, corrosion, or wear, which can lead to overheating, power loss, or system failures. The goal is to ensure all joints maintain minimal resistance, contributing to the overall safety and performance of the aircraft’s electrical systems.

Loop and joint resistance testing is performed on various aircraft systems, including the fuselage and wing bonding, control surface bonding, antenna bonding, and static discharge wicks. It also covers fuel system bonding, hydraulic system bonding, and electrical equipment grounding. Essentially, any system that requires electrical continuity or protection from electromagnetic interference and lightning strikes needs to undergo this testing.

The ExLRT, also known as the XLR-9703-01, is a portable, highly accurate loop and joint resistance tester, specifically built for the aviation industry. It is designed to provide accurate and reliable resistance measurements over long cable runs, making it ideal for testing large aircraft like Boeing’s commercial jets. The robust design of the ExLRT allows this tester to perform under harsh conditions while offering advanced features like data logging and automated test sequences, making it ideal for both routine maintenance and complex diagnostics.

Loop and joint resistance testing should be conducted regularly as part of routine maintenance or whenever electrical system issues are suspected. It is particularly important during inspections after repairs or modifications to ensure that the wiring and joints remain in optimal condition.

The ATEQ AX 6000 is a high-precision milliohmmeter and bonding tester designed to measure loop and joint resistance in aircraft electrical systems. It verifies the integrity of grounding and bonding connections, which are critical for safety, lightning protection, and the prevention of electrical malfunctions. This makes it an essential tool for avionics technicians and maintenance teams working on both commercial and military aircraft.

The AX 6000 offers automated, programmable testing with user-defined thresholds and test durations, making loop and joint resistance checks more efficient and consistent. It eliminates the variability of manual measurement by using a four-terminal Kelvin method, which delivers highly accurate low-resistance readings. This streamlining of the test process supports faster aircraft inspections and reduces the chance of human error.

Unlike basic milliohmmeters, the AX 6000 is specifically engineered for aviation and aerospace applications, with features like real-time resistance monitoring, automatic pass/fail feedback, and programmable test sequences. It includes a large digital display and an intuitive menu system, allowing technicians to quickly configure tests in the field or hangar. Additionally, it stores data for post-test analysis and documentation, helping ensure maintenance traceability and regulatory compliance.

Yes, the AX 6000 is compatible with a wide range of aircraft platforms, from general aviation to commercial airliners and military jets. Its test current ranges from 100 mA to 10 A, allowing it to handle both light-duty and high-resistance bonding applications. This flexibility makes it ideal for testing fuselage joints, wing bonding, lightning protection paths, and other critical grounding systems.

The AX 6000 is designed with simplicity in mind, featuring a user-friendly interface, clearly marked terminals, and automatic test sequences. Its portable design allows technicians to carry and use it easily during ramp inspections, hangar maintenance, or production checks. With built-in safety features and visual pass/fail indicators, it helps ensure technicians perform accurate resistance testing with minimal training.