Cessna 172N accident near Rockford, Idaho, July 16, 2012
On July 16, 2012 at about 3:50 pm local time, a Cessna 172N, registered N5204K, was substantially damaged in an accident during enroute (cruise) near Rockford, Idaho (Rockford Municipal Airport). It was an instructional flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A partial loss of engine power during cruise flight due to the failure of the No. 3 cylinder exhaust valve for reasons that could not be determined due to the damage to the valve head and the missing valve stem. Contributing to the accident was the flight instructor’s improper approach to the runway, which resulted in an aborted landing and subsequent off-airport landing.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 16, 2012 · about 3:50 pm local time
- Place
- Rockford, Idaho · Rockford Municipal Airport · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 172N · all 172Ns on the register
- Registration
- N5204K · no longer on the register · serial 17274009
- Damage
- Substantial damage
- Flight
- Instructional flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The flight instructor reported that, while the airplane was in level cruise flight, the engine began to vibrate, and the rpm dropped to about 1,900. The airplane could not maintain altitude, so the instructor took control of the airplane and chose to divert to a nearby airport. During the approach, the altitude and airspeed were too high to safely land on the runway, so the instructor aborted the landing. He subsequently made a forced landing to an open field. During the landing, the airplane nosed over and came to rest inverted, which resulted in substantial damage to the wings and tail section. A postaccident examination of the engine revealed that the Nos. 2 and 3 cylinders had no compression. A large amount of metal dust and debris were found in the No. 2 cylinder's intake and exhaust ports. The No. 3 cylinder was removed, and the exhaust valve head was found embedded in the cylinder head. The piston head was severely damaged, and the valve stem was missing and had likely exited the engine out of the exhaust. The reason for the failure of the No. 3 cylinder exhaust valve could not be determined due to the damage to the exhaust valve head and the missing valve stem. Although the debris in the No.2 cylinder's ports would have prevented the valve from sealing properly and resulted in reduced compression, it would not have caused the partial loss of engine power as the No. 3 cylinder's failure would have.
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
- Loss of engine power (partial) during enroute (cruise)
- Nose over/nose down during landing (flare/touchdown)
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Failure
- factor Aircraft › Aircraft oper/perf/capability › Performance/control parameters › Descent/approach/glide path › Not attained/maintained
- factor Personnel issues › Action/decision › Action › Incorrect action performance › Instructor/check pilot
Flight instructor
- Certificate: flight instructor, commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 1,939 hours in all; 213 in this make and model; 84 in the last 90 days; 31 in the last 30 days; 1,817 as pilot in command; 649 on instruments
- Last flight review: March 23, 2011
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: rgt
- Injury: no injuries
Dual student
- Certificate: student
- Flight time: 25 hours in all; 10 in this make and model; 11 in the last 90 days; 7 in the last 30 days; 4 as pilot in command
- Medical certificate: Class 3 (without waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 12,691.9 hours
- Last inspection: annual inspection, June 8, 2012
- Maximum gross weight: 2,300 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming O-320-H2AD (piston); 9,466 hours total
- Operator: Teton Leasing LLC
The flight
- Departed from: IDA Idaho Falls ID at 2:35 pm
- Destination: 2U4 Rockford ID
- Flight plan: VFR
- Runway 16, 2,800 ft by 50 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 050° at 6 knots
- Visibility: 10 statute miles
- Sky: broken clouds at 10,000 ft; clear
- Temperature: 73°F (23°C), dew point 55°F (13°C)
- Altimeter: 30.01 inHg
- Observation at 3:53 pm from PIH, 17 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 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 N5204K 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.