What happened
On June 28, 2011, a Cessna 172M, registration N61579, was performing a local flight at Dutchess County Airport (POU) in Poughkeepsie, New York. The flight was intended to verify the operation of a recently replaced horizontal situation indicator. The aircraft departed the airport at 12:07 EDT and entered a left traffic pattern for runway 24.
At 12:09, the pilot reported being on the left downwind leg and received clearance for the option to land or perform a touch-and-go. No distress calls were made to air traffic control. At 12:12:32, radar recorded the aircraft approximately 1/2 mile from the runway 24 threshold at an altitude of 300 feet mean sea level. An air traffic controller observed that while the approach initially appeared normal, the airplane suddenly nosed down and dove into the ground approximately 1/4 mile from the runway threshold. The aircraft impacted the ground at 800 feet above the ground and came to rest inverted. The accident resulted in 2 fatal injuries.
The investigation
Investigators examined the wreckage and found the debris path began with a 3-foot by 5-foot crater and extended 75 feet to the main wreckage. The aircraft's engine and flight controls were inspected, and no mechanical failures were found that would have prevented normal operation. The engine, a Lycoming O-320, showed no signs of internal failure, and the propeller was intact, though one blade showed s-bending from the impact.
An autopsy of the pilot revealed multiple blunt impact injuries, but also identified significant coronary artery disease, specifically 85-90% stenosis in the mid-left anterior descending artery. Toxicological analysis detected atenolol, omeprazole, and warfarin in the pilot's system. While the pilot had reported using omeprazole, he had not reported the use of atenolol or warfarin to the FAA.
Review of the pilot's medical history showed a diagnosis of paroxysmal atrial fibrillation and hypertension three years prior to the accident. Although the pilot had undergone an ablation procedure in 2010, the atrial fibrillation had recurred one month before the crash.