New Alternator Coupling Tools from Approach Aviation


Marlborough, MA – April 12, 2021 – Approach Aviation announced a new set of tools designed for proper installation, removal and testing of alternator drive couplings found on many Continental Aerospace Technologies piston engines.

The alternator drive coupling plays an important role in engines with direct-drive, gear-driven alternators. The coupling provides a shear point; protecting the engine from damage should the alternator fail. However, it is imperative that the coupling be installed properly and inspected every 500 hours or any time that the alternator is removed from the aircraft. This critical component has been the subject of several Service Bulletins (SBs) and Special Airworthiness Information Bulletins (SAIBs) because an out-of-tolerance or improperly installed coupling can lead to catastrophic engine failure.

The lack of specialized tools to perform these tasks has made compliance difficult for many shops, increasing the risk that these critical inspections are not being performed in the field. In addition, alternator coupling slippage is a frequent cause of low alternator output. Without the tools to properly inspect the coupling, these failures are often misdiagnosed as a failure of the alternator, resulting in wasted time and money for both shops and owners.

Approach Aviation’s new Alternator Coupling Tools are purpose-built to make it easy for mechanics to inspect this critical component and simplify coupling installation and removal. The tool kit consists of a zinc-coated coupling spanner wrench and unique coupling gear socket with steel housing and aluminum gear engagement, designed to protect the steel coupling gear from damage during maintenance. Together, these tools allow the coupling to be held in place (mounted on the alternator or free-standing) while the coupling gear slippage is checked with a calibrated 3/8” torque wrench (as specified in the engine maintenance manual).

“Proper installation and inspection of the alternator drive coupling is critical to the safety of these aircraft,” said Jeff Simon, President of Approach Aviation. “We created these new Alternator Coupling Tools to make it easier for shops to perform inspections and also to have a simple way to check the coupling before sending an alternator out for maintenance. It’s a win-win for both safety and efficiency.”

Approach Aviation’s new Alternator Coupling Tools are currently available at a special introductory price of $169.95. The tools can be purchased directly at Approach Aviation (, or from retailers including Aircraft Tool Supply ( and Aircraft Spruce (

For more information, visit Approach or contact Approach Aviation at [email protected] or by calling (877) 564-4457.