On July 25, 2012, a CESSNA 172M (registration N73115) was involved in an aviation accident near San Juan, PR. One person was killed. Investigators recorded the probable cause as: Maintenance personnel’s improper lubrication of the right direct aileron control cable and failure to detect the severe corrosion of the cable during a maintenance inspection, which resulted in the in-flight failure of the cable, the pilot’s subsequent… This summary draws on records from NTSB; 12 related events involving the same aircraft type or operator are linked below.
A Cessna 172M, N73115, impacted water near Fernando Luis Ribas Dominicci Airport on July 25, 2012, after the pilot reported a broken aileron cable. The pilot was fatally injured.
Accident Overview and Flight History On July 25, 2012, at approximately 1420 Atlantic Standard Time, a Cessna 172M, registration N73115, was substantially damaged when it impacted the water near Fernando Luis Ribas Dominicci Airport (TJIG) in San Juan, Puerto Rico. The flight, a personal operation under 14 CFR Part 91, originated from Antonio/Nery/Juarbe Pol Airport (TJAB) in Arecibo, Puerto Rico. Visual meteorological conditions prevailed, and a visual flight rules flight plan had been filed. The private pilot was fatally injured in the accident. Eyewitnesses reported that the aircraft appeared to be in level flight before banking to the right, descending, and impacting the water in a right-wing-down attitude. One witness in a following aircraft noted the plane made some zigzagging before the bank. Security video from a terminal building camera showed the aircraft banking to the right, turning approximately 180 degrees, and impacting the water in a right-wing-low attitude before disappearing beneath the surface within about two seconds. ## Personnel and Aircraft Information FAA records indicated the pilot held a private pilot certificate with an airplane, single-engine land rating. His most recent logbook entry, dated September 30, 2011, showed 1,150.9 total flight hours, while his March 3, 2012, third-class medical certificate application reported 1,175 total hours. The medical certificate included a limitation for corrective lenses. The aircraft, issued an airworthiness certificate on May 14, 1976, and registered to the pilot on December 2, 2002, was equipped with a Lycoming O-320-E2D engine. Maintenance records showed an annual inspection completed on April 13, 2012, at a tachometer reading of 2,999 hours. At the accident site, the tachometer indicated 3,009.6 hours and the Hobbs meter indicated 586.0 flight hours. The most recent entry specifically stating control cable lubrication was recorded on January 22, 2010, at a tachometer reading of 2,913.2 hours. ## Meteorological and Communication Details The 1422 recorded weather observation at TJIG included wind from 110 degrees at 8 knots, visibility of 10 miles or greater, scattered clouds at 4,000 feet above ground level, a temperature of 32 degrees Celsius, a dew point of 24 degrees Celsius, and a barometric altimeter setting of 30.03 inches of mercury. At 1413:00, the pilot made initial contact with the TJIG tower and was instructed to make a straight-in approach to runway nine and report at the Levittown water tank. At 1416:28, the pilot reported abeam the water tank. At 1418:17, the pilot stated, “i think i got my aileron cable broken ah i am unable to maintain level flight so i'll continue the descent and land.” The tower cleared the aircraft to land on runway nine and asked if assistance was required. The pilot replied, “i don't know i guess not.” No further transmissions were received from the aircraft. At 1422:09, another pilot in the area reported the crash. ## Wreckage and Impact Information The aircraft was found submerged in approximately 44 feet of water, 1,490 feet from the threshold of runway 9, slightly south of the extended centerline. The main wreckage was compact, and the aircraft came to rest inverted on the bay floor. The right wing remained attached at the forward attachment point, with crush damage on the outboard 3 feet, 3 inches. The interconnect control cable to both ailerons exhibited broomstrawing, and the right aileron control cable was separated in a manner consistent with tensile overload. The top left doorpost pulley showed scoring on the rim. A section of the right aileron control direct cable, which showed corrosion at the failure point, was sent to the NTSB Materials Laboratory. The empennage exhibited impact damage and fractures aft of the cargo compartment. The left wing remained attached, with crush damage on the outboard 8 feet, 10 inches of the leading edge. The engine remained attached to the firewall by wires and lines, with all engine mount brackets fractured. Saltwater corrosion was observed in the engine and fuel strainer. The propeller remained attached with no S-bending or tip curling. The nose wheel was impact separated and not located. ## Medical and Pathological Findings An autopsy performed on July 26, 2012, found severe bodily trauma and contributing inhalation of water. Forensic toxicology by the FAA Bioaeronautical Sciences Research Laboratory detected no ethanol, cyanide, carbon monoxide, or drugs in the pilot's blood. ## Additional Information and Maintenance Records The NTSB Materials Laboratory examined two sections of the aileron cable and the left door post pulley. The cable separation revealed severe corrosion over about 2 inches, with the majority of wires completely corroded through. The pulley bearing showed moderate corrosion and would not rotate. Four exemplar control cable segments showed areas of corrosion, with coating missing in several areas and a few wires showing section loss. The Cessna Aircraft Company Model 172 Series Service Manual identifies Puerto Rico as a severe corrosion zone. The manual requires checking aileron travel, cable tension, and the aileron cable system every 600 hours or 12 months, whichever occurs first. It also specifies procedures for inspecting control cables for broken wires and corrosion, and for inspecting pulleys for roughness and smooth rotation.