Last week I heard about a Captain that got an LOI for flying a 1900 on a ferry flight. The airplane/engines had been signed off by maintenance as good to go. It was later discovered that one of the compressor or turbine blades in the engine was damaged and unsafe for flight. How a person is supposed to preflight that portion of the engine, I'm still not sure. This is just another example of what's happening over at lakes so make sure you guys are calling mx every time you have a question about anything. I heard about this LOI while sitting in the crew room last week so take it with a grain of salt but it wouldn't surprise me.

Not aircraft specific to your needs for reference only:
EMB120 manual 30-00-00 states 'Patches can be trimmed for small areas, so long as patch extends 1/2 " around damaged area in all directions."

Ask your friendly neighborhood line mechanic...they can give you limits aircraft specific.

I was told for the 1900 as long as the patches do not overlap each other than you can have as many as you want on the wing. 3000 patches next to each other making a deice boot pretty much is legal. They just have to be glued in a way as to not want to start peeling off.

The problem is that I don't trust my friendly neighborhood line mechanic, at least the ones at my company. That is why I'm looking for clarification from another source.

Thanks for everyone's insight thus far.

I've had questions pertaining to MX items before and I called our POI. I would think your company POI would be very helpful pertaining to these types of quesions(our POI is). It's your job to find something wrong, write it up and let MX deal with it.