NTSB Factual Report

On January 31, 1999, at 1212 central standard time (all times herein are central standard time), a Cessna U-206G, N7586N, piloted by an instrument rated private pilot was destroyed during a collision with the ground following a loss of control from cruise flight. The pilot said the airplane's vacuum pump had failed. While making a turn the pilot said he was completely disoriented. Instrument meteorological conditions prevailed at the time of the accident. The 14 CFR Part 91 personal flight was operating on an IFR flight plan to Oklahoma City, Oklahoma. The pilot was fatally injured. The flight had flown into Marion on January 30, 1999, and stayed overnight. The aircraft was refueled for the flight the next day.

0733 - The pilot of N7586N called Columbia AFSS by telephone, obtained a preflight briefing for an IFR flight from Williamson County Regional Airport, Marion, IL to Wiley Post Airport in Oklahoma City, OK and filed an IFR flight plan.

1655 - N7586N called Marion (MWA) Ground Control (GC) to request taxi for departure, IFR to PWA. GC verified N7586N had the current AWOS information and issued taxi instructions to proceed to runway 11.

1657 - GC advised N7586N clearance was available.

1658 - N7586N advised GC ready to copy clearance, copied and read back issued clearance correctly. N7586N was instructed to contact Tower (LC) on tower frequency when ready for departure.

1700 - N7586N called LC ready for departure and received instruction to turn right on course and cleared for take-off runway 11.

1702 - LC instructed N7586N to contact Kansas City Center and call back with flight conditions if tops were determined within 10 NM of MWA. Marion ATCT HAD NO FURTHER CONTACT WITH 7586N.

1655 - Marion ATCT (MWA) called Kansas City ARTCC (ZKC), sector D54 for a clearance on N7586N. D54 issued a clearance for N7586N to PWA via MWA.FAM.SGF.V14.TUL direct PWA to maintain 6,000 feet.

1702 - N7586N reported on R54's frequency departing MWA. R54 acknowledged N7586N.

1705 - R54 issued a relief briefing to the next controller and advised that N7586N had not been radar identified.

1707 - R54 radar identified N7586N and verified his altitude as 4,300 feet. R54 cleared N7586N to climb and maintain 6,000 feet.

1724 - N7586N requested a climb to 8,000 feet to get on top. R54 cleared N7586N to climb and maintain 8,000 feet.

1733 - R54 instructed N7586N to contact ZKC on frequency 133.4. N7586N reported on R52's frequency at 8,000 feet. R52 issued the VIH altimeter setting.

1746 - N7586N advised R52 that he was picking up some ice and requested a lower altitude. R52 cleared N7586N to descend and maintain 6,000 feet and asked if he wanted lower. N7586N advised he would try 6,000 feet.

1750 - R52 issued a relief briefing to the next controller and advised there was icing in the area.

1759 - R52 asked N7586N if he was proceeding direct SGF. N7586N advised he was direct DGD. R52 advised N7586N that she showed his flight plan direct SGF. N7586N advised he would make the adjustment. R52 then instructed N7586N to contact ZKC on frequency 133.8.

1800 - N7586N reported on R72's frequency level 6,000 feet.

1805 - N7586N advised R72 that he had lost his vacuum pump and was experiencing some difficulty. R72 asked N7586N if he needed anything.

1806 - N7586N advised that he was not sure what his heading was except off of the magnetic course. R72 advised that his heading looked like 334 degrees. N7586N requested R72 to give him a heading to fly. R72 issued N7586N a heading of 245 degrees. N7586N acknowledged the heading.

1811 - R72 called R53 and issued a point out on N7586N who had turned eastbound. R72 advised R53 that N7586N had lost his vacuum pump and did not know his heading. R72 then asked N7586N if he was still in a turn. N7586N advised he was trying to stay out of a turn and his artificial horizon was gone and so was his DG. R72 advised N7586N that he was heading totally opposite of the heading that he had been issued. R72 informed N7586N that he was heading about 090 degrees.

1812 - N3635W, a PA28 reported to R72 that he was on top at 6,000 feet. N3635W advised R72 if N7586N could get on top it would help. N3635W was about 35 miles northwest of N7586N at 6,000 feet. R72 informed N3635W that N7586N was southeast of Maples. N3635W advised R72 if N7586N could climb up, he would have to go west to get to VFR conditions. R72 asked N7586N if he needed some help, such as a different altitude. N7586N acknowledged, and informed R72 that he was completely disoriented. R72 asked N7586N if he was in level flight. There was no response. R72 climbed another aircraft in the area from 8,000 feet to 10,000 in case he needed to assign the altitude to N7586N.

1813 - R72 asked N7586N what he could do for him. There was no response. R72 called two more times with no response.

1814 - N3635W advised R72 he would be glad to help. R72 advised N3635W radar and radio contact had been lost with N7586N. He also advised N3635W of what had transpired prior to losing radar and radio contact.

1815 - N3635W suggested that R72 should get hold of Scott Search and Rescue because the aircraft was probably down on the ground. N3635W informed R72 if N7586N had lost his vacuum pump then he was partial panel in the aircraft. N3635W reported the ceilings in that area were about 200 to 300 feet. D72 called Jonesboro Low Sector at Memphis ARTCC (M04) and asked if they could see code 2102. M04 advised they did not see the beacon code. D72 instructed M04 if N7586N did call them to send him back to R72's frequency.

1817 - R72 had N1465G, a Baron, attempt contact with N7586N on 133.8. N1465G was unable to establish communications with N7586N. R72 then instructed N1465G to check for an ELT on 121.5. N1465G advised he did not hear an ELT.

1818 - D72 called M04 and asked them to block 7,000 and down from Springfield along V14 to Farmington.

1819 - D72 was informed that Kansas City Sector 29 was checking to see if anybody could pick up and ELT. R72 gave a sector briefing to the relieving controller and issued all the known data on N7586N.

1823 - R72 called for N7586N with no response.

1826 - D72 called R52 to see if N7586N had contacted them. R52 informed D72 that N7586N had not returned to their frequency, and R52 had attempted to establish communication with N7586N three times with no response.

1833 - R72 called for N7586N with no response.

1834 - N1465G called for N7586N twice with no response. R72 asked N1465G to attempt contact with N7586N on frequency 133.8. N1465G advised he would. There was no response from N7586N on any frequency.

PILOT INFORMATION

The pilot held a Private Pilot Certificate with single-engine land rating and instrument rating. As of April 1998, the pilot had accumulated 526 hours total time, 355 of which were in the accident aircraft make and model.

AIRCRAFT INFORMATION

The aircraft was a 1977 manufactured Cessna U206G, serial number U20603691, registration number N7586N, single engine, high wing model aircraft. The last recorded aircraft inspection was on October 23, 1998, during which a 100 hour inspection was performed in accordance with the Cessna maintenance manual checklist. Total aircraft time on this date was listed at 2121.4 hours. A 100 hour engine inspection was also performed on October 23, 1998, at a listed total time of 2121.4 hours.

On May 28, 1993, a Precise Flight Standby Vacuum System was installed on the aircraft with an FAA Form 337.

WRECKAGE INFORMATION

The aircraft came to rest on the side of a wooded hill. Both wings had separated and were in multiple pieces. The empennage came to rest, downhill of the impact crater. The engine was located at the impact crater. The cabin section of the aircraft was destroyed (See attached Wreckage Impact Diagram and photographs). The vacuum pump and other instruments were located and retained for later detailed inspections (See Tests and Research Section of this report).

The suction gage showed 4.2 inches of vacuum.

Inspection of the aircraft flight control system did not reveal any evidence of any preimpact malfunction.

The three bladed propeller was separated from the engine at the propeller flange of the crankshaft. (See attached photograph).

MEDICAL AND PATHOLOGICAL

According to the Shannon County Coroner, suitable specimens to perform an autopsy were not available. The FAA Civil Aeromedical Final Forensic Toxicology Fatal Accident Report is attached to this factual report.

TESTS AND RESEARCH

The following component tests were conducted under the supervision of the NTSB Investigator in Charge at Waukegan Avionics, Waukegan Regional Airport, Waukegan, Illinois, on February 19, 1999.

Items inspected were the engine driven vacuum pump and drive shaft, tachometer, heading indicator, turn and slip indicator, and a portion of the attitude indicator.

Tachometer

The unit was crushed. The indicator needle showed 2,700 RPM. The recorder section read about 1,973.3 hours.

Vacuum Pump

The unit had separated from the airplane's engine case mounting. It was an Airborne dry vacuum pump, model number 212CW. The serial number was 1CAN3350.

Interior inspection of the unit revealed a shattered rotor.

Six vanes were noted, five were in tact, and one was broken into three pieces (see attached photographs).

The engine driven drive shaft spline teeth were intact. The drive shaft gear teeth were of a consistent shape and size. No damage was observed to either the spline inside the shaft or drive shaft gear teeth.

Placing the drive shaft inside the pump drive section and rotating it did not rotate the rotor. Upon further disassembly it was found that the drive shaft shear coupling had separated. The separation surfaces were clean, one being slightly convex, the other being slightly concave. No debris was noted in the shear coupling area within the pump body. The coupler had the number "98" on one end of the drive shaft attachment section. The pump stator section had a wash boarding texture and was pitted in various areas.

There were six vacuum pump vanes inside the pump body. Five of the six vanes were intact. The sixth vane was separated into three major pieces. The intact vanes were inspected and measured. Numbering of the vanes was random and for reference only.

Vanes One through Five

Both ends were .835 inches long

Both ends were .835 inches long

Both ends were .835 inches long

Both ends were .834 inches long

Both ends were .834 inches long

Sixth Vane

Too damaged to measure

Heading Indicator

No face on this instrument. Examination of the gyro rotor revealed no rotational scuffing or scarring except for one scuffmark which did not appear to be part of a rotational action. The case which surrounds the rotor also did not have any scuffing or scar marks on its surface except for one mark that did not appear to be part of a rotational action. An imprint was found on the case interior surface that appeared to match the shape of a vane on the rotor. There was a scuffmark next to, and merging onto, the imprint found on the rotor case which appeared to match the scuffmark on the rotor surface next to the vane cutout.

Turn and Slip Indicator

The unit is powered by electric power. There was no face or indicator needle. The unit was crushed. Examination of the armature revealed no scarring or scuffing. No scarring or scuffing was observed in the case, which surrounds the armature. The surfaces of this area were pitted with a brown colored material.

Attitude Indicator

The unit was crushed. The face had separated from the instrument and was crushed also. The face did not have any definable marking on it that would match the airplane silhouette normally installed.

There was no rotor. The rotor case had fractured and the rotor was ejected. The rotor was not recovered. The inner surfaces of the rotor case had rotational scuffing and scarring.

NTSB Probable Cause

the spatial disorientation and loss of control by the pilot after a reported vacuum failure. Factors were instrument flight conditions and icing conditions.