Had to troubleshoot a faulty VHF comm unit on a Citation last Friday.

Started with the old method of swapping the whole LRU based on the MEL, which took about two hours with the paperwork. Then I actually pulled the fault codes from the central maintenance computer and it pointed right to a bad coax run behind the panel. Fixed the connector in thirty minutes. Why do some shops still default to the LRU swap before a proper diagnostic pull?

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3 Comments

nancy3916mo ago

Our shop in Tulsa still bills by the hour, so swapping the LRU first makes financial sense. It’s a guaranteed fix for the customer and covers our labor if the diagnostics lead to a wild goose chase. Sometimes the old way is just the safer bet for everyone involved.

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hollyr286mo ago

My buddy Jake at a shop in Dayton wasted three hours last week chasing a bad sensor reading. Turned out the whole module was fried. Could have just swapped it and been done by lunch.

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terrywalker5mo ago

Yeah @hollyr28, I've seen that exact thing happen at my place too.

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