Problems with the Fan Blades
The blades on your fans are metal and can bend or break, particularly on the outdoor unit; they can also come loose from operation. If a blade is bent, it can hit other components around it as it spins, potentially causing damage
Essential components of your air conditioning system (and most electro-mechanical machines) are the capacitors. A capacitor is used to store energy in an electrostatic field. Attached to motors, capacitors perform the job of stabilizing voltage and providing the necessary jolt to start the motor in the first place. In an air conditioner, capacitors are connected to the three main motors: the compressor motor, the blower motor, and the outdoor fan motor. Each of these has a separate capacitor to start it up (the start capacitor) and to keep it running (the run capacitor).
Failing capacitors are one of the common reasons for malfunctions in an AC. Thankfully, if you catch capacitor problems in time, repair technicians and easily swap them out for new ones without any serious effect to the AC. However, if bad capacitors are ignored, you may end up with a non-functioning air conditioning system right when you need one the most.