Skyhawk 172/Cutlass 172
Flight Crew Commercial; Flight Crew Flight Instructor
Aircraft Equipment Problem Critical
Flight Crew Rejected Takeoff
Aircraft
Upon entering [runway] I had my student line up on the centerline of the runway and administer full power for takeoff. The student put in full power smoothly without any issues. At this point I made sure my student was keeping the aircraft straight down the runway; and moved my view point to the airspeed indicator; and then the engine gauges which were all sustained in their normal operating ranges. I looked at the tachometer which was also reading normal RPM's for takeoff. Approximately 4-5 seconds after I checked these instruments we experienced a loss of power. Both myself and the student heard the engine RPM reduce significantly. This loss of power occurred and lasted around 2 seconds. I took the flight controls of the aircraft and promptly aborted takeoff; notified ATC; applied brakes and exited the runway normally. I am positive that my student did not move the throttle in any way which would have caused the RPM decrease that we saw on takeoff. I estimate we lost approximately 300-400 RPM when the drop occurred.
Flight instructor assumes control from student pilot and rejected the takeoff when he heard a significant reduction in engine power for unknown reasons.