Cessna 172 accident near Hernando, Florida, June 21, 2024
On June 21, 2024 at about 4:10 pm local time, a 1977 Cessna 172, registered N734XT, was substantially damaged in an accident during maneuvering near Hernando, Florida. 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).
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The NTSB's probable cause their words, unchanged
The improper installation of a cylinder rocker stud by maintenance personnel, which resulted in a partial loss of engine power and subsequent forced landing.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- June 21, 2024 · about 4:10 pm local time
- Place
- Hernando, Florida · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 172 N, built 1977 · all 172s on the register
- Registration
- N734XT · registry record · serial 17269203
- 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, during an instructional flight, while maneuvering about 2,000 ft above ground level, the engine began to run rough and lost partial power. The airplane could not maintain altitude and the instructor was unable to restore engine power. He subsequently performed a forced landing on a road, during which the left wing impacted a tree and the airplane came to rest inverted. Subsequent examination of the engine revealed that the No. 3 exhaust valve rocker was loose and did not depress the exhaust valve when the pushrod was fully extended. The rocker and stud were removed and remnants of threads from the cylinder head were observed between the threads of the stud, consistent with over-tightening of the stud during installation. Review of maintenance records revealed that the No. 3 cylinder was replaced due to low compression about 13 months and 564 engine tachometer hours before the accident. Although the maintenance procedures specified that the stud be tightened to 150 ft-lbs of torque, the stud was likely over-tighten during installation, as was evident by cylinder thread material being pulled into the stud threads, which resulted in its looseness and inability of the rocker to open the exhaust valve.
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
- Off-field or emergency landing during emergency descent
- Collision with terrain or object (not controlled flight into terrain) during landing
- Loss of engine power (partial) during maneuvering defining event
The NTSB's findings
- Personnel issues › Task performance › Maintenance › Installation › Maintenance personnel
- Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Incorrect service/maintenance
Flight instructor
- Certificate: flight instructor, commercial pilot
- Ratings: single-engine land; instructor: airplane single-engine; instrument: airplane
- Flight time: 1,192 hours in all; 1,000 in this make and model; 174 in the last 90 days; 55 in the last 30 days; 1,130 as pilot in command; 830 on instruments
- Last flight review: April 19, 2023
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: left
- Injury: no injuries
Pilot
- Certificate: commercial pilot
- Ratings: single-engine sea; instrument: airplane
- Flight time: 271 hours in all; 100 in this make and model; 19 in the last 90 days; 10 in the last 30 days; 213 as pilot in command
- Last flight review: June 14, 2022
- Medical certificate: Class 3 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
The aircraft
- Airframe total time: 8,309 hours
- Last inspection: 100-hour inspection, April 19, 2024
- Maximum gross weight: 2,300 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming O-320-H2AD (piston); 8,309 hours total
- Operator: American Aviation INC
The flight
- Departed from: BKV Brookville FL at 3:44 pm
- Flight plan: none
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 030° at 4 knots
- Visibility: 7 statute miles
- Sky: overcast at 3,400 ft; scat at 2,600 ft
- Temperature: 84°F (29°C), dew point 73°F (23°C)
- Altimeter: 30.09 inHg
- Observation at 12:15 pm from INF, 23 miles away
Weather report (METAR): KINF 211615Z AUTO 03004KT 7SM SCT026 OVC034 29/23 A3009
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flig | 2 |
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The docket at the NTSB holds the report as a PDF and the investigation's photographs and documents. This site never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number ERA24LA271.