NTSB Factual Report

On September 3, 2015, about 1710 eastern daylight time (EDT), a Cessna R172K, N758DK, was destroyed by collision with terrain during a forced landing following a total loss of engine power near Cresskill, New Jersey. The private pilot and pilot-rated observer were seriously injured. The flight departed Republic Airport (FRG), Farmingdale, New York, about 1400. Visual meteorological conditions prevailed, and no flight plan was filed for the public use flight.

According to the United Stated Coast Guard (USCG), the flight was conducted as a USCG Auxiliary Maritime Observation Mission.

Federal Aviation Administration (FAA) inspectors interviewed the pilot in the hospital the day after the accident. Due to his injuries, the inspectors conducted only a brief interview. According to the pilot, he departed Lincoln Park, New Jersey (N07) about 1300 and flew to Farmingdale, New York (FRG) to pick up the observer for the flight. They then departed FRG, and flew to the Albany, New York area where they reversed course and flew south along the Hudson River. While in cruise flight about 2,000 feet mean sea level (msl), the airplane's engine stopped producing power.

During the subsequent descent, the pilot selected a large open area adjacent to a community center that contained several athletic fields for the forced landing. As the airplane approached, the pilot observed that the fields were in use, and that only a small space was available for landing which would allow separation from people on the ground. The resultant hard landing destroyed the airplane and required first responders to affect the egress of the airplane's occupants.

According to FAA and USCG records, the pilot held a private pilot certificate with a rating for airplane single engine land. His most recent FAA third-class medical certificate was issued on April 20, 2015. The pilot updated a USCG Pilot/Aircrew Qualification form on April 30, 2015, and reported 510 total hours of flight experience on that date. According to the FAA, the pilot reported he had 648 total hours of flight experience, of which 382 were in the accident airplane make and model.

The four-seat, single-engine, high-wing, retractable-gear airplane was manufactured in 1978 and was equipped with a Continental Motors 210-horsepower reciprocating engine. According to the FAA, the airplane's maintenance records showed the most recent annual inspection was completed on July 17, 2015, at 2,194 total aircraft hours. The hobbs meter indicated 2,281 total aircraft hours at the accident site.

Review of engine maintenance records revealed the #3 and #4 cylinders had been removed and reinstalled for maintenance on May 11, 2012. The engine accrued approximately 231.5 hours of operation prior to the accident.

Examination of photographs revealed the accident site was located in a hedgerow on the perimeter of an athletic field about 41 feet elevation. The wreckage path was approximately 36 feet long, oriented about 130 degrees magnetic. The tail section and empennage appeared intact, but the roof and wingbox structure appeared collapsed into the cockpit and cabin areas. The airplane came to rest in about a 30-degree, right wing-down attitude. The right wing was visible, and remained intact from the cabin to about mid-span, where it wrinkled and curled upwards towards the tip.

The airplane was removed from the accident site, and the engine was shipped to the manufacturer for a detailed examination at a later date.

The engine was examined at the manufacturer's facility under the supervision of an FAA aviation safety inspector. Examination revealed impact damage to the fuel pump housing, and the right magneto, which had a broken mount flange and was hanging loose from the engine. The right front engine mount was broken and several ignition harness leads were severed.

The cylinder flange nuts were checked for security and breakaway torque, and the #2 and #3 cylinders' through bolts nuts and perimeter nuts were below factory specifications. The #2 cylinder through bolts breakaway torque was 236/365 in. lbs. respectively. The #3 cylinder through bolts breakaway was 286/351 in. lbs. respectively. The manufacturer's specification was 590-610 in lbs.

Removal of the engine oil pan revealed metal fragments and bearing material in the sump. Disassembly of the crankcase revealed damage to the #1 and #2 main bearings and bearing journals consistent with a loss of lubrication, high heat, and fatigue.

Fretting was noted around the #1, #2, and #3 through bolt bosses as well as the #2 and #3 cylinder deck pads.

The crankshaft was fractured through the #4 throw.

NTSB Probable Cause

Maintenance personnel’s failure to apply proper torque to the cylinder flange nuts and through bolts during installation of the engine cylinders, which resulted in the loosening of the components, loss of lubrication, failure of the crankshaft, and the subsequent total loss of engine power.