More fun than a barrel of grease monkeys

Over the summer I spent a few weeks working with an aircraft mechanic in a full-service hangar at Blodgett Memorial Airport (KHTL) in Houghton Lake, Michigan. I am not a certified mechanic, so there were some limits as to what I could do. However, this did not diminish the skills I was able to learn.
There are different levels of aircraft mechanics. Anyone who has received a mechanic certificate from the Federal Aviation Administration (FAA) is considered an Aircraft Maintenance Technician and can perform and supervise aircraft maintenance. In order to do 100-hour and annual inspections, where you check a plane for airworthiness and hopefully declare it in good flying condition, you need to be a licensed Aircraft & Powerplant mechanic with an Inspection Authorization (IA). 
A Piper Cherokee sits in the hangar for annual inspection.
A Piper Cherokee sits in the hangar for annual inspection.
The mechanic I worked for has an IA, so I mostly helped with annual inspections. Annuals check for airworthiness in three categories: engine, propeller, and airframe. You basically check the plane part by part to make sure everything is in good working order. This is a necessary safety measure because experiencing any sort of failure while in the air can have the potential to be fatal. It’s for this same reason that airplane engines have duality (for example two sparkplugs per cylinder, two magnetos).  
Checking the engine includes procedures such as cleaning or replacing spark plugs, changing the oil, replacing filters, checking the alternator condition, looking over the engine mount for cracks, and making sure all gaskets and seals are in good condition. 
Checking the propeller means removing it and checking its mechanical system as well as sharpening the blades and repairing cracks/nicks as necessary. 
And checking the airframe means checking every other moving part of the plane, as well as looking over the entire body for damage. This also means disassembling sections of the wings, fuselage, and rudder in order to check the cables, etc. within. 
Normally it’s also necessary to remove the cockpit seats and floor. Sometimes this is more work than it sounds. While working on someone’s Cessna 172, I needed to take out a couple floor panels that were located behind the rudder pedals along the firewall. To reach the screws, which were sunk into the seam and couldn’t actually be seen, I had to lay on my stomach in the cockpit with my legs over the back seats and my head under the yoke. That way I could reach up to the firewall and feel for the screws.  
I also had jobs like cleaning sparkplugs and packing wheel bearings. One day was mostly spent washing the school plane, which took a while since leading edges have a tendency to get coated in bug splats.  
It was honest dirty work and a good time. I’m happy to have done it and I’m grateful for the opportunity I had.
P.S. Here is a joke for whoever appreciates it. When pilots and mechanics don’t get along:
Pilot reports, “Suspected crack in windshield.”
Mechanic replies, “Suspect you’re right.”
Pilot says, “There’s something loose in the cockpit.”
Mechanic’s answer: “I tightened something in the cockpit.”
Pilot complains, “The plane is flying funny.”
The mechanic says, “I’ll tell it to shape up and fly right.”