ATS E5A Cable Tester

How to know if your ignition cables are good.


Aircraft Tool Supply recently bought Eastern Technology’s test equipment line and has set about making important, if incremental, improvements. The E5A cable tester is among those newly revised tools. (See our review of the E50A magneto synchronizer in the September 2021 issue.) ATS has been carefully altering the guts of these test tools without changing their essential function.

The E5A is an ignition-harness tester. Those of you running electronic ignition and auto-style plug wires can turn the page. The rest of us, who need to determine if an ignition-system malfunction is in the mag, plug or harness itself, will find the E5A useful. Put simply, the E5A simulates a mag-fired spark (up to 20,000 volts) and looks to see if the ignition lead is in good condition. The tester returns an unambiguous blue arc in the test window when the cable is good to go. No arc means a cable is in need of attention or replacement. The buzzing sound makes you feel like you’re in Dr. Frankenstein’s lab or something.

Connect one of the red leads (it’s obvious which one) to the free end of the high-tension cable (left) to start the test. If the cable is in good condition, a blue arc will appear in the test window (right). No arc, you have a bad cable. Simple as that.

Setup is simple. Connect to the aircraft’s battery (either 12 or 24 volts), then connect the test lead to an exposed end of the ignition harness. Push the button, see what happens. Chances are good you won’t need this tool anytime soon, but at $129.95, it’s a nice piece to have in a shared toolbox.

For more information:
Aircraft Tool Supply Company,; 800-248-0638.

Photos: Marc Cook.

Previous articleGlasair Sportsman Kits Available Again
Next articleTodd Sonex Onex
Marc Cook
Marc Cook is a veteran special-interest journalist who started as a staffer at AOPA Pilot in the late 1980s. Marc has built two airplanes, an Aero Designs Pulsar XP and a Glasair Aviation Sportsman, and now owns a 180-hp, steam-gauge-adjacent GlaStar based in western Oregon. Marc has 5000 hours spread over 200-plus types and four decades of flying.


Please enter your comment!
Please enter your name here

This site uses Akismet to reduce spam. Learn how your comment data is processed.