Cessna 172K accident near Neenah, Wisconsin, August 2, 2016
On August 2, 2016 at about 11:30 pm local time, a 1969 Cessna 172K, registered N46459, was substantially damaged in an accident during enroute (cruise) near Neenah, Wisconsin. It was a personal flight under general aviation rules (Part 91). No one was hurt; 3 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A loss of engine power due to oil starvation, which resulted from the pilot, who was not a certified airframe and powerplant mechanic, removing the vacuum pump from the engine, and his misconception that he could operate the airplane without the pump.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 2, 2016 · about 11:30 pm local time
- Place
- Neenah, Wisconsin · map
- Type
- Accident
- Injuries
- No one was hurt; 3 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 172K, built 1969 · all 172Ks on the register
- Registration
- N46459 · no longer on the register · serial 17257282
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The private pilot was conducting the first flight in the airplane after having removed a failed vacuum pump from the engine; the pilot was not a certified airframe and powerplant mechanic. During the flight, the engine lost power, and the pilot subsequently landed the airplane on a highway, and the left wing contacted a road sign, which resulted in substantial damage. The pilot reported that he had recently had a mechanic remove a failed vacuum pump on a different airplane that he owned and that he was able to fly that airplane without the pump. As a result, he thought he could also fly the accident airplane without a vacuum pump. However, the vacuum pumps were mounted on each airplane differently, and the pilot's removal of the vacuum pump on the accident airplane allowed oil to exit the engine through the drive gear opening on the accessory case, which resulted in oil starvation.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Powerplant sys/comp malf/fail during enroute (cruise) defining event
- Collision with terrain or object (not controlled flight into terrain) during landing (landing roll)
The NTSB's findings
- cause Personnel issues › Experience/knowledge › Experience/qualifications › Qualification/certification › Pilot
- cause Personnel issues › Task performance › Maintenance › Unauthorized maint/repair › Pilot
- cause Personnel issues › Action/decision › Action › Incorrect action performance › Pilot
- cause Aircraft › Fluids/misc hardware › Fluids › Oil › Fluid level
- cause Personnel issues › Psychological › Perception/orientation/illusion › Perception › Pilot
- Environmental issues › Physical environment › Object/animal/substance › Sign/marker › Contributed to outcome
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 1,610 hours in all; 1,262 in this make and model; 9 in the last 90 days; 7 in the last 30 days; 1,610 as pilot in command
- Last flight review: August 11, 2015
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 4,640.6 hours
- Last inspection: annual inspection, June 20, 2016
- Maximum gross weight: 2,299 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming O-320 SERIES (piston); 0 hours total
The flight
- Departed from: 79C Neenah WI at 11:15 pm
- Destination: 79C Neenah WI
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 220° at 7 knots
- Visibility: 10 statute miles
- Sky: scat at 3,800 ft
- Temperature: 82°F (28°C), dew point 63°F (17°C)
- Altimeter: 30.03 inHg
- Observation at 10:45 pm from ATW, 3 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 2 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
Other NTSB records under N46459 the same tail number, which may have belonged to a different aircraft at the time
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.