On July 23, 2011, about 1210 eastern daylight time, a Cessna 172S, N869BC, owned and operated by Aero Safety Training LTD, crashed into a guardrail when it overran the runway during landing at Lincoln Park Airport (N07), Lincoln Park, New Jersey. The pilot and passenger were not injured and the airplane incurred substantial damage. Visual meteorological conditions prevailed and no flight plan was filed for the personal flight, which was conducted under the provisions of 14 Code of Federal Regulations Part 91. The flight originated from N07, about 1200. The pilot stated that the accident airplane had experienced an electrical problem the day before the accident during a cross country flight. The operator’s maintenance personnel were flown to the airport where the airplane was located to correct the discrepancy, which was attributed to a stuck electrical contactor. The mechanic was able to start the airplane and the pilot flew it back to N07. On the morning of the accident, the operator’s mechanic was in the process of replacing an electrical contactor when the pilot arrived for the airplane. He was advised they needed additional time to complete the replacement. About an hour later, he was informed the airplane was ready for him. No discrepancies were noted during the preflight inspection, ground run-up check, and initial takeoff. Shortly after takeoff, the airplane had a complete electrical system failure. The pilot elected to return to N07 and land on runway 01. Unable to operate the airplane’s electrical flaps, he stated he landed with a slightly higher airspeed, touching down on the runway one quarter to one third of the available runway length. He added that due to the airplane’s poor braking performance; it was not possible to stop the aircraft on the remaining runway, resulting in a runway overrun and impact with a guardrail before coming to a full stop. A witness stated that he observed the accident airplane forcibly land approximately 2/3 down runway. The airplane was traveling at a very high rate of speed, both tires were skidding and smoking at which point the left main tire blew out. It was at this point, the airplane’s directional control was lost and it veered off centerline. The airplane continued skidding until it collided with a guardrail separating the field and the road. After the airplane came to a stop, both occupants exited the airplane. The pilot, seated in the left seat, held a private pilot certificate with a rating for airplane single engine land. He was issued a Federal Aviation Administration (FAA) second class medical certificate on November 27, 2008, with limitations, and reported at the time of the accident he had a total of 141 hours, which 37 of those hours were in accident airplane make and model. The Cessna 172S, a four place, all metal, high wing, single-engine airplane, with tricycle landing gear, manufactured in 2004, and issued a standard airworthiness certificate, in the normal & utility category. The airplane was powered by a Lycoming IO-360-L2A, 180-horsepower engine, equipped with a two blade fixed pitch propeller. The airplane’s last inspection was an annual inspection on June 28, 2011. At the time of the accident the airplane had a total of 2,404.6 hours. The airplane’s pilot operating handbook (POH) states that the airplane is approved for a no flap landing; which indicates that with a temperature of 30 degrees Celsius and a pressure altitude of 2,000 feet, with no flaps, the desired speed would be no slower than 74 knots and no faster than 84 knots, and that the required runway length would be 1,945 feet. The POH also states that the procedure for a loss electrical power, if not corrected, to land as soon as possible. Published information for runway 1/19 at N07 shows it as asphalt, 2,942 foot long by 40 foot wide, with a 840 feet displaced threshold for runway 01, at an elevation of 182 feet mean sea level (msl). The airport does not have a control tower and runway 01 is not equipped with a visual slope indicator. Information cautioning trees at the approach end of runway 01 & 19 are published. The closest official weather observation was at Morristown Municipal Airport (MMU), Morristown, New Jersey about 10 miles northeast of the accident site. The MMU 1545 METAR was wind from 010 degrees at 6 knots, visibility 10 statute miles, and scattered clouds at 12,000, temperature 32 degrees Celsius (C), dew point 20 degrees C, and the altimeter setting was for 29.93 inches of Mercury. A postaccident examination of the airplane by the responding (FAA) inspector revealed the engine nacelle area, propeller spinner, propeller, engine, nose landing gear, and firewall sustain substantial damage. The airplane’s wheel braking system revealed no preimpact mechanical irregularities when examined. The airplane’s electrical system trouble shooting did revealed discrepancies with the master control unit (MCU), which was retained by the NTSB for further testing. The MCU along with the 2 electrical contactors that were replaced from within the MCU prior the accident flight were examined by Cessna with FAA oversight. The contactors located at the battery and alternator positions within the unit were incorrect. The two contactors should have been the type for continuous operation, but were instead for intermittent operation. The contactor in the battery position of the unit malfunctioned due to an electrical overheating and the subsequent parting of one of the internal copper lead wires.