NTSB Factual Report

HISTORY OF FLIGHT

On August 22, 2004, about 1335 central daylight time, a Cessna 172E, N5410T, piloted by a private pilot, was destroyed when it impacted the ground about 5 statute miles north of the Decorah Municipal Airport (DEH), Decorah, Iowa. The 14 CFR Part 91 personal flight was operating in visual meteorological conditions on a visual flight rules (VFR) flight plan. The pilot was seriously injured. The two passengers were fatally injured. The airplane had departed DEH just prior to the accident and was en route to Isle, Minnesota.

In a written report, the pilot stated that he remembered performing a pre-flight inspection and run-up of the airplane. He stated that he had no recollection of the accident flight subsequent to announcing his intention to takeoff on the radio. The pilot made no mention of any discrepancies detected during the pre-flight inspection or the run-up.

A witness reported that he was at DEH working in his hangar at the east end of the runway when he heard an aircraft back-taxi for runway 29. He stated that the airplane was "an older Cessna 172, red and white in color." The witness stated that he heard the run-up check of this airplane and noticed that the run-up seemed unusual because "it sounded like the pilot was cycling through a constant speed propeller as the RPM was not the sound of the normal 1,700 RPM magneto and carburetor heat run-up check that a typical Cessna 172 should be expected to make." He stated that the rpm drop seemed very high in comparison to the allowable rpm drop.

The witness stated that he saw the takeoff. Based on his experience of operating a 1969 Cessna 172 for over 17 years, he noted that the accident airplane was not accelerating as he would expect a Cessna 172 to accelerate. He stated that the sound of the engine was smooth, but that he did not believe that it was developing full power during the takeoff. The witness stated that he exited his hangar to observe the accident airplane. He again stated that the airplane's acceleration was not fast enough for a normal takeoff. The witness stated that he observed no attempt to stop or slow the airplane. He stated that he observed the airplane rotate twice and then lifted about 3 feet off of the runway before it came back down left wing high and subsequently bounced into the air. He stated that at this point, the airplane was now over the end of the runway. The witness stated that he was alarmed that the airplane was not gaining altitude and he then lost sight of it behind some large trees. He stated that he believed that continued flight would not be possible due to the degraded performance.

PERSONNEL INFORMATION

The pilot held a private pilot certificate with a rating for single-engine land airplanes. The pilot also held a third-class medical certificate issued on June 3, 2003. The medical certificate listed no limitations.

According to a logbook found at the accident site, the pilot had accumulated 139.5 hours total flight experience including 5.6 hours in the previous year, 3.3 hours in the previous 90 days, and 2.3 hours in the previous 30 days. All of the flight time recorded was in Cessna 172 airplanes.

AIRCRAFT INFORMATION

The airplane was a Cessna 172E single-engine airplane powered by a 145 horsepower Continental model O-300 engine. The airplane was a strut-braced, high-wing, fixed landing gear, monoplane, of predominately aluminum construction.

The maintenance records for the airplane showed that the most recent annual inspection was performed on October 21, 2003. At the time of that inspection, the airplane had accumulated 3,955 total hours time in service. The engine had accumulated 1,755 hours since overhaul.

METEOROLOGICAL INFORMATION

The DEH recorded weather conditions at 1335 were: Wind 220 degrees at 8 knots, gusting to 17 knots; Visibility 10 statute miles; Sky condition 8,000 feet scattered; Temperature 26 degrees Celsius; Dew point 21 degrees Celsius; Altimeter setting 29.84 inches of mercury.

WRECKAGE AND IMPACT INFORMATION

The accident site was approximately 5 nautical miles north of DEH. The coordinates of the accident site were 43.3539 degrees north latitude, 91.7601 degrees west longitude.

The airplane fuselage and wings forward of the tail cone came to rest inverted on an embankment adjacent to a local road. The forward fuselage was crushed rearward to the forward door posts. The left wing was bent aft and exhibited crushing of the leading edge. The right wing exhibited leading edge crushing. The wings remained partially attached to the fuselage structure. Both wing struts were intact and remained attached. Both ailerons remained attached and all hinges were intact. The tail cone of the airplane aft of the cabin section was separated and twisted in a clockwise direction. The tail cone was resting on the ground upright. The horizontal stabilizer, elevator, vertical stabilizer and rudder remained attached to the aft fuselage. All of the tail surface hinges remained intact. Examination of the control system confirmed control cable continuity from the respective control surface to the cockpit. The fuel selector was positioned on "both" and could be rotated to all positions. Detents were detected in each respective fuel selector position.

Examination of the engine revealed that the crankshaft could be rotated. Valve action and compression were confirmed on all cylinders when the crankshaft was rotated by hand. Both magnetos were removed from the engine for examination. The right magneto case was shattered. Disassembly of the remains of the right magneto failed to reveal any pre-impact defects. The left magneto remained intact. The left magneto did not produce any sparks when rotated by hand. Disassembly of the magneto revealed that the contact points were not opening when the input shaft was rotated. Both attachment screws for the contact points were in place. The screws were able to be rotated with minimal effort. The investigation did not reveal when maintenance was last performed on the magneto's points.

MEDICAL AND PATHOLOGICAL INFORMATION

The pilot sustained serious injuries and remained hospitalized for several months following the accident.

The passenger that was seated in the front right seat was fatally injured.

The passenger that was seated in the rear of the airplane initially survived the accident. This passenger passed away on August 28, 2004.

ADDITIONAL INFORMATION

The Federal Aviation Administration and Cessna Aircraft Company were parties to the investigation.

NTSB Probable Cause

The pilot's intentional operation of the airplane with a defective magneto, his failure to abort the takeoff due to degraded aircraft performance, and his failure to obtain or maintain airspeed which resulted in a stall/spin and subsequent impact with the ground. Contributing factors were the improper installation of the magneto's contact points by unknown entities due to undertorque of the mounting screws which led to the loss of engine power.