NTSB Factual Report

HISTORY OF FLIGHT

On June 28, 2011, at 1212 eastern daylight time, a Cessna 172M, N61579, registered to Millbrook Flight LLC., and operated by a private individual, was substantially damaged when it nosed over and impacted the ground during short final approach to runway 24 at Dutchess County Airport (POU), Poughkeepsie, New York. The airline transport pilot and passenger were fatally injured. The personal flight was conducted under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed and no flight plan was filed for the local flight, which departed POU about 1207.

According to the owner of the airplane, a mechanic had replaced the airplane's horizontal situation indicator just prior to the accident flight. The pilot wanted to conduct a brief local flight to verify that the new instrument operated correctly, and offered the mechanic a ride in the airplane.

Review of air traffic control (ATC) audio data and radar data, provided by the Federal Aviation Administration (FAA), revealed that the airplane departed POU at 1207, and remained in a left traffic pattern for runway 24. At 1209, the pilot reported that the airplane was on a left downwind leg and the controller cleared the flight for the option to land or touch-and-go on runway 24. No distress calls or further radio communications from the accident airplane were received by ATC. The last radar target was recorded at 1212:32, about 1/2 mile from the runway 24 threshold, indicating an altitude of 300 feet mean sea level.

According to an ATC controller in the POU tower, the airplane was on final approach and everything appeared normal. Approximately 1/4 mile from the runway threshold, about 800 feet above the ground, the airplane nosed down, dove straight into the ground, and came to rest inverted.

PILOT INFORMATION

The pilot, age 60, held an airline transport pilot certificate with a rating for airplane multiengine land. He also held a commercial pilot certificate, with ratings for airplane single-engine land and airplane single-engine sea. The pilot also held a flight instructor certificate, with ratings for airplane single-engine, airplane multiengine, and instrument airplane. The pilot's most recent FAA second-class medical certificate was issued on February 23, 2011. At that time, the pilot reported a total flight experience of 14,750 hours. The pilot's logbook was not recovered.

AIRCRAFT INFORMATION

The four-seat, high-wing, fixed tricycle-gear airplane, serial number 17264654, was manufactured in 1975. It was powered by a Lycoming, O-320, 150-horsepower engine. Review of the aircraft logbooks revealed that the airplane's most recent annual inspection was completed on February 17, 2011. At that time, the airplane had accumulated 4725.0 total hours of operation. The engine had accumulated 4,725.0 total hours of operation, and 1,151.7 hours of operation since major overhaul. The airplane had flown about 49 hours since the annual inspection.

METEOROLOGICAL INFORMATION

The reported weather at POU, at 1153, was: wind calm; visibility 10 miles; few clouds at 4,100 feet; temperature 27 degrees Celsius; dew point 18 degrees Celsius; altimeter 29.89 inches Hg.

WRECKAGE INFORMATION

A debris path originated with an approximate 3-foot by 5-foot crater, and extended approximately 75 feet on a 250-degree magnetic course to the main wreckage. The debris path consisted of ground scars and the nose landing gear. The ground scars were consistent with landing gear contact, in a nose-low, left wing low, left crab angle at ground impact. The airplane came to rest inverted on a heading of about 180 degrees magnetic, with the empennage partially separated and canted left. Evidence of a small postcrash fire was noted in the vicinity of the carburetor.

Both wings remained attached to the airframe, with the ailerons and flaps attached to their respective wing. The ailerons were approximately neutral and measurement of the flap jackscrew corresponded to an approximate 20-degree flap extended position. The fuel caps remained secured to their respective wing fuel tanks, and approximately 2 to 3 gallons of fuel were observed in each wing. Additionally, fuel staining and browning vegetation was noted, consistent with fuel leakage after the accident. The remaining fuel was clear and light blue in color, with no visible contamination observed. The horizontal stabilizer, vertical stabilizer, rudder, and elevator remained intact and undamaged. Measurement of the elevator trim jackscrew corresponded to an approximate neutral trim position. Flight control continuity was confirmed from the cockpit controls to the flight control surfaces.

The cockpit was crushed; however, the seatbelts and shoulder harnesses remained attached. The mixture control was in the full rich position, the carburetor heat control was off, and the throttle control was about 1 inch from the full throttle position. Additionally, both magnetos were selected and the engine primer was in and locked.

The engine remained partially attached to the airframe and the propeller remained attached to the engine. One propeller blade exhibited s-bending and chordwise scratching, while the other blade was undamaged. The engine was separated from the airplane and the propeller was removed from the propeller flange to facilitate further examination of the engine. The valve covers were removed and oil was noted throughout the engine. The spark plugs were also removed for inspection; their electrodes were intact and light gray in color. When the crankshaft was rotated by hand, camshaft, crankshaft, and valvetrain continuity were confirmed and thumb compression was attained on all cylinders. Both magnetos produced spark at all leads when rotated by hand. Inspection of the carburetor revealed that the floats and needle valve remained intact. Fuel was found in the fuel line from the gascolator to the carburetor. Examination of the oil filter did not reveal any contamination. The vacuum pump remained attached to the engine and was disassembled for inspection. The drive coupling, rotor, and rotor vanes remained intact. Rotational scoring was noted on the rotor and vacuum pump housing.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy was performed on the pilot on June 29, 2011, by the Dutchess County Office of the Chief Medical Examiner, Poughkeepsie, New York. Although the autopsy report noted the cause of death as multiple blunt impact injures, it also noted:

"Focal high grade stenosis of mid-left anterior descending artery due to atherosclerotic cardiovascular disease… Coronary arteries show focal atherosclerosis as follows: in the right coronary artery there is 10% stenosis; in the mid-left anterior descending coronary artery there is 85-90% stenosis; in the left circumflex coronary artery there is 10-20% stenosis."

Toxicological testing was performed on the pilot by the FAA Bioaeronautical Science Research Laboratory, Oklahoma City, Oklahoma.

Review of the toxicology report revealed:

"Atenolol detected in Liver

Atenolol detected in Blood (Heart)

Omeprazole detected in Blood (Cavity)

Warfarin detected in Urine

Warfarin detected in Blood (Heart)"

Review of the pilot's FAA medical records, dating back to 1988, revealed "No" for items 18g and 18h (heart or vascular trouble and high or low blood pressure) on his applications for airman medical certificates. Additionally, the pilot did not report the use atenolol, a medication that treats hypertension and slows the heart rate, or the use of warfarin, a blood thinner. He did report the use of a medication for heartburn similar to omeprazole.

Review of the pilot's personal medical records revealed that in 2008, he was found to have paroxysmal atrial fibrillation and hypertension, complicated by thrombosis of the ulnar artery, which was believed to have been embolic. Initially, the pilot’s paroxysmal atrial fibrillation was controlled with warfarin anticoagulation and rate control medications, but in 2010, he was increasingly symptomatic, even while on medications. He elected to undergo a procedure to ablate the foci initiating the abnormal rhythm. The procedure was initially successful with a return to normal sinus rhythm, but by May 2011, the atrial fibrillation recurred and medications were restarted. It was unclear from the records what quality of heart rhythm and rate control was achieved in the weeks leading up to the airplane accident.

Report of atrial fibrillation to an FAA aviation medical examiner would have been initially disqualifying for a medical certificate. For pilots with well controlled rates, who were mostly asymptomatic and without concomitant coronary artery disease, could be issued a special issuance medical certificate with appropriate follow-up. Such follow-up would have included stress testing that most likely would have detected his undiagnosed coronary artery disease.

NTSB Probable Cause

The pilot’s loss of airplane control due to impairment or incapacitation as a result of coronary artery disease in combination with atrial fibrillation. Contributing to the accident was the pilot's failure to report his paroxysmal atrial fibrillation to the Federal Aviation Administration, which would have required follow-up testing that would likely have detected his undiagnosed coronary artery disease.