I am a new and still inexperienced operator. On a training flight a gust of wind caught my phantom upon landing. It was about 3 feet above the ground and flipped it sideways. It has the flight guards on and broke 1 propeller. After replacement, 1 of the other motors will not start. It tries to but if I spin it by hand, it starts and makes a squealing sound. When the revs are increased this motor does not increase.

Have I damaged the motor or is there something else at fault? Thank you for any replies.

It did happened to me also, what I had to do is completly dissasemble the motor and blow air with a compressor until all dust and sand will be thrown out (visually check with a magnifier) oil all the parts before reassemble the unit and make sure it will freely turn with your hand before mounting it on its wing.

Did you remove the prop guards ?
And if you did, did you use the original shorter screws ?

Sounds like the bearing in the motor has failed.