CHI05FA048

The airplane collided with trees and terrain during a forced landing following a loss of engine power. Approximately 8 minutes after taking off, the pilot reported to air traffic control that the cabin of his airplane was filling with smoke and he was diverting to a near-by airport. The airplane contacted 30 to 40 foot tall trees which bordered an open field. The airplane then contacted the terrain and a post impact fire ensued. Inspection of the engine revealed two holes in the crankcase near the number four cylinder with the number four piston rod separated from the crankshaft. Teardown of the engine revealed five cylinder deck stud nuts were missing and the number five cylinder seventh stud had sheared. The crankshaft, counterweights, and rod bearings exhibited thermal damage which was most prominent at the number four cylinder connecting rod journal. Material from the number four connecting rod bearing was fused to the crankshaft journal displacing the oil tube toward the number three main journal. The cylinders had been removed and overhauled approximately 380 hours prior to the accident. The cylinder base packings on all of the cylinders were flattened and extruded between the base of the cylinders and the crankcase. The cross section diameter of the packings was larger than a sample packing, part number 641066, which is used on IO-520-BA engines. The cross section diameter of the base packings that were removed from the engine were similar in diameter to those used on the O-470 series engines.

History of flight

On December 25, 2004, at 1021 central standard time, a Beech S35, N5631K, collided with trees and the terrain in Herman, Wisconsin, following a loss of engine power during flight. The airline transport pilot and a passenger were fatally injured. The airplane was substantially damaged by impact with the terrain and a post impact fire. The 14 CFR Part 91 personal flight was operating in visual meteorological conditions on an instrument flight rules (IFR) flight plan. The airplane departed the Manitowoc County Airport (MTW), Manitowoc, Wisconsin, at 1010, en route to the Lewis University Airport (LOT), Romeoville, Illinois. The pilot was attempting to divert to the Sheboygan Memorial Airport (SBM), Sheboygan, Wisconsin, when the accident occurred.

Records compiled by the Federal Aviation Administration (FAA) indicate the following:

At 0545, the pilot requested weather information through a direct user access terminal (DUATS).

At 0620, the pilot filed an IFR flight plan and requested weather information through DUATS.

At 0703, the pilot called the Green Bay Flight Service Station for an IFR weather briefing for a flight from MTW to LOT.

At 1006, Green Bay (GRB) air traffic control tower (ATCT) issued an IFR clearance to N5631K for a flight from MTW to LOT.

At 1010, the pilot reported to GRB ATCT that N5631K was airborne.

At 1011, radar contact was established with N5631K.

At 1012, N5631K was issued a frequency change to contact the Chicago air route traffic control center (ZAU). At 1012:51, N5631K contacted ZAU and reported being at 4,000 feet.

At 1018:42, N5631K reported to ZAU that they had an emergency. The controller asked what the emergency was and the pilot replied that the cabin was filling with smoke and they were heading for Sheboygan.

The controller instructed N5631K to descend and maintain 3,000 feet. The controller also informed N5631K that SBM was 5 miles away at their 10 o'clock position.

At 1019:32, the controller asked the pilot if he had the airport in sight. The pilot replied that the airport was in sight.

At 1019:36, the controller cleared N5631K for the visual approach to the airport and told the pilot that he could cancel his IFR flight plan through N800MW. The pilot of N5631K responded, "three one kilo." This was the last radio contact with N5631K.

At 1025:06, another airplane reported hearing a weak ELT signal in the area.

Five witnesses were identified who either heard or saw the airplane just prior to the accident.

One witness stated his attention was drawn to the airplane by the sound of trees snapping. This witness stated he did not hear the engine running prior to the airplane contacting the trees. The witness stated that one to two minutes after the airplane impacted the ground he heard a "poof" sound and observed flames coming from the airplane. He stated that it was not an explosion.

Another witness reported seeing the airplane flying west at an altitude of about 200 feet above ground level (agl). This witness stated the engine was running rough.

A third witness reported seeing the airplane flying at an altitude of 200 to 400 feet agl. This witness stated the engine was "sputtering" and then it stopped.

A fourth witness, who was at his residence about 500 yards east of the accident site, stated he heard the airplane fly over his house. He stated the engine was very loud and that it "shook the house" as it flew overhead. This witness did not hear the impact, but did see smoke and flames coming from the field.

A resident of a farm adjacent to the accident site stated he heard the airplane fly overhead and also heard it contact the trees. This witness stated the airplane's altitude was approximately twice the height of his barn when it flew overhead. He stated the engine was running slow. He stated he noticed a "black strip" by the door.

Personnel information

The pilot held an airline transport pilot certificate with a multi-engine land rating. The certificate contained commercial pilot privileges for single-engine land and single-engine sea airplane ratings. The pilot also held a flight instructor certificate with single-engine land, multi-engine land, and instrument airplane ratings. His instructor certificate was last renewed on November 2, 2003.

The pilot held a third class medical issued on November 17, 2004. The medical certificate contained the limitation, "Holder shall wear lenses that correct for distant vision and possess glasses that correct for near vision. Not valid for any class after November 30, 2005."

The pilot completed Phase VII of the FAA Pilot Proficiency Wings program on September 1, 2004.

The last entry in the pilot's most recent logbook was dated December 16, 2004. According to the logbook, the pilot had a total flight time of 4,515.7 hours, of which 4,348.1 hours were logged as pilot-in-command. This logbook indicated the pilot had flown 643.3 hours in a Beech 35.

The pilot's logbook indicated that he took possession of N5631K on August 30, 2003. Since that date, the pilot logged 205.4 hours in the airplane.

Aircraft information

N5631K was a low wing, V-tail, 1964-model Beech S35, serial number D-7389. According to FAA records, N5631K was registered to the pilot on December 13, 2003.

According to the aircraft logbook, the last annual inspection on the airplane was completed on June 16, 2004, at a tachometer time of 957.8 hours and a total aircraft time of 5,496.5 hours. The last maintenance entry in the aircraft logbook was dated December 22, 2004. This entry listed the tachometer time of 1,076.5 hours. The tachometer reading at the time of the accident was 1,076.8 hours.

The airplane was powered by a Teledyne Continental Motors IO-520-BA, serial number 280883-R. This remanufactured engine was installed in N5361K on October 9, 1993, at a tachometer time of 206.03 hours. On June 10, 1998, the cylinders were removed for a top overhaul. This occurred at a tachometer time of 696 hours which was 490 hours after the engine had been remanufactured.

The last annual inspection of the engine was on June 16, 2004, at a tachometer time of 957.8 hours. At the time of this inspection the engine total time was listed as being 751.8 hours with a time since overhaul of 261.8 hours. The entry previous to the annual inspection was for an oil change on October 6, 2003, at a tachometer time of 884.0 hours.

The mechanic who maintained the airplane stated the pilot routinely performed his own oil changes. He stated that in November 2004, the pilot informed him that there was fuel streaking down the left side of the fuselage. The mechanic stated that he inspected the airplane and did not find a fuel leak, but he did find a small oil leak.

The mechanic stated that in December 2004, the fuel return line in the right wing split, so he replaced the lines in both of the wings. He stated he also changed the push rod tube seals on the number six cylinder since the seals were leaking. He stated he wanted to replace the remainder of the push rod seals along with some other work, but the pilot wanted to wait until he returned from flying the airplane to Florida and the Bahamas.

The mechanic stated that on December 21 and 22, 2004, after the pilot returned from his trip, he replaced the sending unit gasket for the left tip tank. He stated he also installed an EZ oil sump heater. The mechanic stated that as he was inspecting the engine, he noticed the seventh stud on the number five cylinder was broken. The mechanic stated that this must have happened recently because it was not broken when he worked on the engine earlier in the month and he found the broken section of the stud in the bottom of the engine cowling. The mechanic stated he did not have the manuals or the tools to replace the stud, so they contacted an engine shop about doi