Started using a torque wrench on spark plugs after seeing 3 come loose on a regional jet

I've been working on planes for about 5 years now and always just did spark plugs by feel... you know, tight enough. Then last month we had a CRJ come in with 3 loose spark plugs on the same engine. One was barely hanging on. My lead told me he's seen plugs back out and cause misfire issues mid-flight more than once. Now I torque every single one to spec. Takes an extra 30 seconds but man... that's 30 seconds I don't mind spending. Has anyone else had a close call because they skipped the torque wrench on something small?

2 comments

2 Comments

iris_burns22d ago

... yeah and the thing is, it didn't even happen to me but to a buddy of mine who works at a different shop. He was doing a top overhaul on a little Piper and just snugged the plugs by hand with a ratchet, no torque wrench. About 50 hours later the pilot comes back complaining of rough running. One of the plugs had backed out so far it was barely making contact and the threads were all chewed up. He had to pull the cylinder and helicoil it. Took him like 4 hours of labor and the customer was pissed. He never skips the torque wrench now either. It's one of those lessons you really only need to learn once.

colemartinez22d ago

Oh man, that's rough but I've been there too. I did the same thing on my own car years ago, thought I had it tight enough and it backed out on the highway, total mess. Now I double check every spark plug with a torque wrench even if I'm just swapping them for a buddy.