21 Oct 2023: CESSNA 172L

21 Oct 2023: CESSNA 172L (N7716G) — Unknown operator

No fatalities • Richmond, VA, United States

Probable cause

The loss of engine power due to a restriction of fuel flow as a result of a fractured float bracket in the carburetor.

— NTSB Determination

Accident narrative

On October 21, 2023, at approximately 1340 EDT, a Cessna 172L, N7716G, was substantially damaged when it was involved in an accident near Richmond, Virginia. The flight instructor, student pilot, and one passenger were not injured. The airplane was operating as a Title 14 Code of Federal Regulations Part 91 instructional flight. The flight instructor reported that the purpose of the flight was to conduct a review of flight maneuvers in a designated practice area. On the return flight to OFP, the engine began to lose power. The power loss progressed until the airplane could no longer maintain level flight. The flight instructor initiated an emergency landing in an open field short of the runway. During the landing rollout the right wing struck a tree, resulting in substantial damage. A Federal Aviation Administration inspector conducted an on-site examination and noted that the right wing exhibited damage consistent with impact with a small tree located at the accident site. The cabin section showed damage at the right-wing root attachment area. The left wing displayed upward bending from the wingtip about 2 feet inboard. An engine examination established valvetrain continuity with crankshaft rotation through 720°. Ignition continuity was confirmed during the examination of the magnetos, ignition wires, and spark plugs. An undetermined amount of fuel sufficient for flight was found in both fuel tanks. The carburetor was partially disassembled. It was observed that the float bracket had fractured into two pieces. The float remained attached to the bracket by the float lever shaft, and the float valve was coupled to the float by a clip mounted on the float lever shaft. The float’s movement along the shaft allowed axial motion of the float valve within the float valve seat, restricting fuel flow into the bowl when the valve sealed against the seat. The carburetor components were submitted to the National Transportation Safety Board (NTSB) Materials Laboratory for further examination. Analysis revealed that one arm of the float bracket had fractured due to cyclic fatigue. The fracture surface was flat with radiating lines and curved crack growth features consistent with fatigue failure. The origin of the fracture was along the interior edge where the bracket arm intersected the base of the bracket. No anomalies were observed at the fracture origin. A review of the logbook excerpts revealed that in 2005 there was an IRAN (Inspect & Repair As Necessary) performed that referred to the replacement of the various original accessories including the carburetor. No other maintenance was noted on carburetor since 2005.

Contributing factors

  • Fatigue/wear/corrosion

Conditions

Weather
VMC, wind 180/08kt, vis 10sm

Loading the flight search…

What you can do on Flight Finder

  • Search flights between any two airports with live fares.
  • By aircraft — pick a plane model (e.g. Boeing 787, Airbus A350) and see every route it flies from your origin.
  • Route map — click any airport worldwide to explore its destinations, or draw a radius to find nearby airports.
  • Global aviation safety — aviation accident database, 5,200+ records since 1980, with map and rankings by aircraft and operator.
  • NTSB safety feed — recent U.S. aviation accidents and incidents from the official NTSB CAROL database, updated daily.

Frequently asked questions

How do I search flights by aircraft type on FlightFinder?

Pick an aircraft model — Boeing 737, Airbus A320, A380, Boeing 787 Dreamliner and more — enter your origin airport, and FlightFinder shows every route that plane flies from there with live fares.

Which aircraft types can I filter by?

We support Boeing 737/747/757/767/777/787, the full Airbus A220/A319/A320/A321/A330/A340/A350/A380 family, Embraer E170/E175/E190/E195, Bombardier CRJ and Dash 8, and the ATR 42/72 turboprops.

Is FlightFinder free to use?

Search and schedules are free. Pro ($4.99/month, $39/year, or $99 one-time lifetime) unlocks the enriched flight card — on-time stats, CO₂ per passenger, amenities, live gate & weather — plus My Trips with push alerts.

Where does the route data come from?

Live schedules come from Amadeus, AeroDataBox and Travelpayouts. Observed routes (which aircraft actually flew a given city pair) are crowdsourced from adsb.lol ADS-B data under the Open Database License.