The pilot in the second helicopter manoeuvres the aircraft on to the pad when its rotor blades strike the first helicopter's blades.
The collision causes the rotor blades to rip apart and fly in different directions.
Both aircrafts are destroyed leaving debris scattered across the heliport pad.
A man who was standing on the heliport pad at the time of the crash is knocked to the ground.
He jumps up and sprints away from the wreckage towards safety as the pilots from both helicopters climb out of their severely damaged helicopters.
Police said six people were injured in the November 17 crash, including five officers aboard the helicopters and the civilian who had been standing on the heliport pad. They were all hospitalised with minor injuries and released.
Pasadena Police Chief Phillip Sanchez told NBC at the time that the returning helicopter had been monitoring traffic for the Rose Bowl and came back to the heliport pad because of weather conditions.
The other helicopter was getting ready to takeoff and respond to a call in the area.
Sanchez told the outlet that it was the first time police helicopter rotor blades had collided causing an accident.