NTSB Factual Report

HISTORY OF FLIGHT

On January 21, 1997, at 1807 eastern standard time, a Cessna 210N, N29WW, was lost on radar four miles south southwest of Pontiac, Michigan. The business flight operating under provisions of 14 CFR Part 91, departed Troy, Michigan, about 1755 with the intended destination of Oshkosh, Wisconsin. The flight was operating on an IFR flight plan. The destroyed airplane and two fatal instrument rated pilot occupants were located on January 22, 1997, near Highland, Michigan. The airplane had sustained an in-flight separation of an outboard twelve foot section of the right wing, which was found about one-half mile northwest of the main wreckage. The reported weather at Pontiac, Michigan, was visual meteorological conditions; however, residents near the accident site reported to the investigator that freezing rain was falling at the approximate time of the event.

At 1748 an individual identifying himself as the pilot of N29WW called the Lansing (Michigan) Federal Aviation Administration (FAA), Automated Flight Service Station (AFSS), requesting a weather briefing for a proposed flight from Troy, Michigan, to Oshkosh, Wisconsin. A transcript of that conversation is attached as an addendum to this report. The pilot stated during the initial portion of his request that he was "concerned with icing conditions en route... ." He was told by the AFSS briefer that there were advisories for moderate to isolated severe turbulence along the route of flight; however, an inversion indicated temperature above freezing at the proposed cruising altitude. The pilot concluded the telephone conversation with the filing of an IFR flight plan.

The flight departed at 1755. At 1801 the flight was cleared to climb to 5,000 feet. At 1807 the last recorded transmission from the accident airplane was, "Niner whiskey whiskey req... ." There was no transmission indicating any difficulty or problem and no Mayday. Radar contact with N29WW was lost at 1807.

A search was initiated for the airplane. Initially the outboard section of the right wing was found where it had impacted trees and the terrain along a county road. The search continued in that area until the main wreckage was located on January 22, 1997, in a boggy area about one-half mile southeast of the wing panel.

PERSONAL INFORMATION

Both occupants were pilots. They were seated in the two front seats of the airplane and both had access to the controls. The occupant of the left front seat was the individual who was listed on the IFR flight plan as the pilot-in-command.

The pilot in the left seat, born December 17, 1947, was the holder of a commercial pilot certificate, with privileges for single engine land along with an instrument rating. His most current FAA medical examination was on July 2, 1996, when he received a second class medical with the restriction to have available glasses for near vision. At the time of that examination he listed a total pilot time of 600 hours. No personal log books were located for this pilot.

The pilot in the right seat, born November 2, 1939, was the holder of a private pilot certificate, with privileges for single engine land along with an instrument rating. His most current FAA medical examination was on May 31, 1996, when he received a second class medical with the restriction to wear corrective lenses for near and distant vision. At the time of that examination he listed a total pilot time of 325 hours. No personal log books were located for this pilot.

AIRCRAFT INFORMATION

The airplane was a Cessna 210N, N29WW, serial number 21063308. At the time of the accident the airframe had accumulated 2,027 hours time in service. The most recent inspection was an annual inspection conducted on April 10, 1996, at 1,809 hours. The engine had a total of 477 hours since the most recent overhaul. The transponder, altimeter, and static check was last performed on April 8, 1996.

METEOROLOGICAL INFORMATION

The surface observation for Pontiac, Michigan, about four miles from the accident site, at 1745 was ceiling 2,000' overcast, visibility eight statute miles, temperature 33 degrees (F), dewpoint 26 degrees (F), wind 170 degrees at 6 knots, altimeter 30.02" Hg.

The surface observation for Pontiac, at 1815 was ceiling 1,500' overcast, visibility three statute miles in fog, temperature 33 degrees (F), dewpoint 28 degrees (F), wind 170 degrees at 15 knots, altimeter 30.00" Hg.

The surface observation for Pontiac, at 1845 was ceiling 1,100' overcast, visibility three statute miles in fog and drizzle, temperature 33 degrees (F), dewpoint 28 degrees (F), wind 170 degrees at 14 knots, altimeter 29.99" Hg.

Police officers who were searching for the airplane (after the accident occurred) indicated that the weather in the area of the impact included freezing drizzle. They stated that the light drizzle was freezing on contact with the ground.

Weather forecasts were for an inversion about 1,500' with the freezing level above 8,000'. There were no pilot reports, or flight advisories for icing conditions for the planned flight at 8,000', at the point of departure, en route, or at the destination airport.

WRECKAGE AND IMPACT INFORMATION

During the on-scene investigation the major components of the airplane were accounted for. Both the primary flight control surfaces and the trim surfaces were operated via closed cable and bellcrank systems. The fuselage and right wing were shredded. There were no preexisting defects identified.

The wreckage site was divided into three separate locations. The fuselage, left wing, and engine were located in an open bog field. The outboard twelve feet of the right wing was 2,080' from the fuselage on a heading of 319 degrees magnetic in a wooded area. Several small portions of the empennage were on the same general direction as the wing from the fuselage extending out to about one mile from the main crater.

The fuselage was removed from the crater to extricate the fatally injured occupants prior to the arrival and initial examination by the NTSB investigator in charge. Pictures of the wreckage taken at the main crater by the initial responders, indicated the recognizable structure consisted of the tail surfaces, left wing spar, and left wing tip. The remainder of the fuselage, engine, and propeller were located below the empennage to a depth of fifteen feet in the crater.

After removal from the crater, the wreckage was moved to a remote location for further inspection. The left wing was identified. Wing skins were separated from both the upper and lower surfaces. Both the upper and lower main wing spars had upward bending at the fracture point. The left flap was partially attached to the wing with the exception of one foot of the most outboard section. The left aileron remained attached to the left wing.

The tailcone was twisted about 90 degrees to the right as viewed looking forward. The right and left horizontal stabilizers, and the vertical stabilizer had compression damage to the leading edge for about one-third of their span. The rudder remained attached to the stabilizer as did both the right a left elevators. The rudder balance weight was separated, but located in the crater. The outboard section of the right elevator with a portion of the trim tab was separated. The trim tab fractured about one foot outboard of the trim tab actuator rod attach bracket. The inboard portion of the trim tab was found about one mile northwest of the crater. The trim tab hinge rod separated from the right elevator and remained with the recovered portion of the tab. The inboard portion of the trim tab and some small portions of the right elevator were never identified.

Maintenance records indicate that the artificial horizon was changed on January 18, 1996, and again on December 20, 1996. The instrument was located, disassembled and found to have internal scoring on both the rotor and rotor housing. The airplane was equipped with a standby vacuum pump. The primary vacuum pump was disassembled and found to have dirt and water ingested into the vanes where the rotor fractured.

The propeller had bending and twisting for the entire span. There was gouging of the leading and trailing edges of all three blades. One blade was released from the hub. The spinner was crushed with twisting opposite the direction of rotation. The engine driven mechanical tachometer had the needle trapped at 2500 RPM. There was no indication of preexisting mechanical failure of the engine.

MEDICAL AND PATHOLOGICAL INFORMATION

An autopsy was performed on both occupants by the Oakland County Michigan, Office of the Medical Examiner. The cause of death in both instances was stated to be from impact injuries. The reports from the post mortem examinations reported no identifiable natural disease contributing to the deaths.

Toxicological examination of tissue from the pilot in command revealed ethanol in the muscle fluid and acetaldehyde detected in the kidney tissue. The finding of ethanol was reported by the FAA to be from post mortem production.

Toxicological examination of specimens from the second pilot were negative for drugs screened.

ADDITIONAL DATA/INFORMATION

Parties to the investigation were the FAA Flight Standards District office, Detroit, Michigan; Cessna Aircraft Company, Wichita, Kansas; and Teledyne Continental Motors, Mobile, Alabama.

The airplane was released to a representative of the owners on January 23, 1997.

NTSB Probable Cause

in-flight breakup of the airplane for undetermined reason(s).