What happened
On the runway 25R run-up area, two aircraft were positioned for departure. The Cessna 172S, registration N431ER, was positioned ahead of a Cessna 172R, registration N864CP.
A student pilot requested takeoff clearance and received instructions from the tower to maneuver around the preceding aircraft to prepare for departure. During this maneuvering process, the left wing of the student pilot's aircraft struck the tail of the lead aircraft. This impact caused the student pilot's airplane to rotate further to the left until the propeller made contact with the trailing edge of the right wing of the first aircraft.
Following the collision, the pilot and flight instructor shut down their engine and secured their aircraft. The flight instructor then assisted the student pilot in securing his aircraft.