Why does nobody talk about how long it takes to chase a wire in an old 737?

I ran into a nagging fault on a 737-300 last month. The MEL said it was a cabin light intermittent, so I figured 30 minutes tops. Three hours later I was still pulling panels in the forward galley because the wire took a weird detour behind the lav. Turns out the original installers ran it through a bundle that crossed the entire crown. I finally traced it to a chafed spot near a galley bracket. That little fix ate up my whole afternoon. Has anybody else spent way too long hunting a simple short on these old birds?

2 comments

2 Comments

jade_hunt485d ago

Old 737s are basically a rat's nest of wiring. That crown detour you found is a known thing on the -300s especially. They rerouted stuff in later builds but the early ones are a total mess. Chafing near galley brackets is also super common because the vibrations loosen things over time. Next time just pull the main panel and check the galley area first. It'll still take longer than the three page book says but not as bad.

viola1715d ago

Oh come on, I gotta push back on this one @jade_hunt48! The wiring in those old 737s isn't that bad if you know the tricks. Yeah the crown detour is a pain but calling it a "rat's nest" is kinda dramatic. I've worked on -300s where the main panel gave me zero trouble and the galley area was actually clean. The chafing near the brackets can be an issue sure, but it's not like it's happening on every single frame. Honestly I think the book time is fine, people just get scared by the age of the plane and start looking for problems that aren't there. If you go in with a good attitude and some patience it's really not the nightmare everyone makes it out to be.