Cessna 206 accident near Sugar Land, Texas, September 19, 2018
On September 19, 2018 at about 8:04 pm local time, a 2005 Cessna 206, registered N247F, was substantially damaged in an accident during approach (VFR pattern final) near Sugar Land, Texas (Sugar Land Regional airport). It was a public-use flight (federal) under public-use (government) rules. 1 person had minor injuries; 2 others were unhurt. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
Fatigue failure of the No. 1 cylinder intake valve, which resulted in the loss of engine power.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 19, 2018 · about 8:04 pm local time
- Place
- Sugar Land, Texas · Sugar Land Regional · map
- Type
- Accident
- Injuries
- 1 person had minor injuries; 2 others were unhurt.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 206 H, built 2005 · all 206s on the register
- Registration
- N247F · registry record · serial 20608247
- Damage
- Substantial damage
- Flight
- Public-use flight (federal) · public-use (government) rules
The NTSB's narrative final · quoted from the NTSB record
The airline transport pilot and the flight instructor were conducting an instructional flight in a public aircraft with an observer on board and proceeded to an airport to conduct instrument approaches. After crossing the final approach fix and before arriving at the missed approach point, the engine lost power. The instructor took control and maneuvered the airplane over a set of power lines. He attempted to maneuver under a second set of power lines when the right wing struck one of the lines. The airplane touched down on a roadway, and its left wing struck a passing vehicle. The landing gear struck the concrete median, yawing the airplane clockwise, and the airplane's tail struck a second vehicle. Postaccident engine examination revealed the No. 1 cylinder intake valve had failed. Fractured pieces of the intake valve had been drawn into the intake plenum. The No. 1 cylinder was extensively damaged, and all of the piston heads had impact marks or pieces of valve embedded in the heads. The No. 1 cylinder, No. 1 piston, its intake and exhaust valve train components (springs, pushrods, and rocker arms), and 12 hydraulic lifters were sent to the engine manufacturer for metallurgical examination, which revealed that the No. 1 cylinder intake valve had failed in fatigue; however, the root cause of the failure could not be determined due to the extensive damage after the valve failure. Both the intake and exhaust rocker arms had nonconforming shoe heights. In addition, nine of the hydraulic lifters failed the leak-down test, including the No. 1 intake. Maintenance information revealed the engine had been overhauled 4 years earlier, during which all 12 hydraulic lifters were replaced. The intake and exhaust rocker arms had been reworked and reused, and about 0.01 inch of material had been removed from the shoe pads during the overhaul. While the nonconforming rocker arm shoe height and lifter may have contributed to a malfunction of the valve, the investigation could not determine with certainty the reason for the fatigue failure. The fatigue failure of the No. 1 cylinder intake valve resulted in the loss of engine power.
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
- Loss of engine power (partial) during approach (VFR pattern final) defining event
- Collision with terrain or object (not controlled flight into terrain) during uncontrolled descent
- Collision with terrain or object (not controlled flight into terrain) during after landing
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › Recip engine power section › Failure
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Fatigue/wear/corrosion
- Environmental issues › Physical environment › Object/animal/substance › Wind sock › Contributed to outcome
- Environmental issues › Physical environment › Object/animal/substance › Ground vehicle › Contributed to outcome
- Environmental issues › Physical environment › Object/animal/substance › Wall/barricade › Contributed to outcome
Pilot
- Certificate: airline transport pilot, flight instructor, commercial pilot, private
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instrument: airplane; rotorcraft: helicopter
- Flight time: 4,919 hours in all; 1,044 in this make and model; 124 in the last 90 days; 46 in the last 30 days; 4,638 as pilot in command; 128 on instruments
- Last flight review: May 18, 2018
- Medical certificate: Class 1 (without waivers/limitations)
- Seat: rgt
- Injury: no injuries
Pilot
- Certificate: commercial pilot, private
- Ratings: single-engine land; instrument: airplane
- Flight time: 328 hours in all; 205 in this make and model; 118 in the last 90 days; 34 in the last 30 days; 228 as pilot in command
- Last flight review: August 16, 2018
- Medical certificate: Class 1 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 3,636 hours
- Last inspection: annual inspection, August 9, 2018; 45 hours since
- Maximum gross weight: 3,605 lb
- Seats: 3
- Landing gear: fixed
- Engine: Lycoming IO-540-AC1A5 (piston); 3,621 hours total
The flight
- Departed from: KCXO Conroe TX at 7:00 pm
- Destination: KCXO Conroe TX
- Flight plan: none
- Runway 17, 8,000 ft by 100 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 210° at 3 knots
- Visibility: 10 statute miles
- Sky: a few clouds at 4,700 ft
- Temperature: 93°F (34°C), dew point 73°F (23°C)
- Altimeter: 29.92 inHg
- Observation at 7:53 pm from KSGR, 1 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 2 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
18 documents, released by the NTSB on June 25, 2019. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
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.