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CEN21FA198 · Piper PA-46-310P

23 Apr 2021 · Danville, AR, United States

Piper PA-46-310P · Accident: structural icing en route

From Muskogee-Davis Regional Airport (MKO) to Williston Municipal Airport (X60)

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Event

NTSB case
CEN21FA198
Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
Accident
InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
Completed
API-reported fatalities
4 · all aircraft and ground
Ground fatalities
Unknown
OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
General aviation
WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
Instrument Meteorological Cond

Piper PA-46-310P

Aircraft type
Piper PA-46
Category
Airplane
RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
N461DK
Operator
Unknown
Onboard fatalities
Unknown
Route
From Muskogee-Davis Regional Airport (MKO), Muskogee, OKTo Williston Municipal Airport (X60), Williston, FL
Aircraft age
About 36 years (built 1985)
Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
Part 91: General Aviation
Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
En route · climb to cruise
Defining eventThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
Structural icing
DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
Substantial

Cause areas

  • Aircraft › Aircraft oper/perf/capability
  • Environmental issues › Conditions/weather/phenomena
  • Personnel issues › Action/decision
  • Personnel issues › Experience/knowledge

Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.

NTSB narrative

The pilot was conducting an instrument flight rules cross-country flight and climbing to a planned altitude of 23,000 ft mean sea level (msl). According to air traffic control data, as the airplane climbed through 18,600 ft msl, its groundspeed was 171 knots, and a gradual reduction in groundspeed began. After reaching an altitude of about 20,200 ft msl, the airplane began a descent on a southeast heading. Just before the descent began, the airplane’s groundspeed had decreased to 145 knots. About 2 minutes after the descent began, the airplane turned right to a northeast heading on which it continued for about 30 seconds. The flightpath then became erratic before the data ended. The pilot made no distress calls and did not respond to repeated calls from the controller.

The main wreckage of the airplane was located in densely forested terrain at an elevation of about 930 ft about 1,000 ft south of the last radar return. The outboard portion of the right wing, right aileron, right horizontal stabilizer, and right elevator were not located with the main wreckage and, despite ground and aerial searches with a small unmanned aircraft system, were not found. Examination of the wreckage indicated that the missing wing and tail sections separated in flight due to overload. Examination of the recovered airframe and engine did not reveal evidence of any pre-existing mechanical malfunctions or anomalies that would have precluded normal operation.

Weather forecasts indicated that the accident site was in an area where moderate icing conditions up to 25,000 ft msl, embedded thunderstorms, and 2-inch hail were forecasted. Review of preflight weather information received by the pilot indicated that he was aware of the conditions forecast on the route of flight before initiating the flight. Meteorological data revealed that the airplane likely entered icing conditions that ranged from light to heavy as it climbed through 14,000 ft msl about 23 minutes after takeoff and remained in icing conditions for the remaining 16-minute duration of the flight. Freezing drizzle conditions were likely present along the flightpath. Although the airplane was equipped for flight in icing conditions, the pilot’s operating handbook contained a warning about flight into severe icing conditions, which stated that flight in freezing drizzle could result in ice build-up on protected surfaces exceeding the capability of the ice protection system. The airplane’s gradual loss of groundspeed as it climbed was consistent with ice accumulating on the airplane. It is likely that during the 16 minutes the airplane was operating in icing conditions, the capability of the ice protection system was exceeded, which resulted in a degradation of aircraft performance and subsequent aerodynamic stall. During the ensuing uncontrolled descent, the structural capability of the airplane was exceeded, which resulted in an inflight break up.

A review of the pilot’s records revealed multiple certificate application failures for reasons that included inadequate knowledge of cross-country flight planning, aircraft performance, and stalls. Review of the pilot’s airman knowledge written tests found areas answered incorrectly over multiple exams included meteorology, aircraft performance, aeronautical decisionmaking, and stalls.

The ethanol identified in the pilot’s cavity blood was most likely the result of postmortem production. Therefore, effects from ethanol did not play any role in this accident.

The cargo was documented as it was removed from the airplane and remained secure until after it was weighed. Based upon the weight of the cargo, passengers, airplane, and fuel from the filed flight plan, at the time of departure, the airplane would have been about 361 lbs over maximum gross weight. According to the FAA Pilot’s Handbook of Aeronautical Knowledge, an overloaded airplane “may exhibit unexpected and unusually poor flight characteristics,” which include reduced maneuverability and an increased stall speed.

Probable cause

The pilot’s improper decision to continue flight in an area of moderate-to-heavy icing conditions, which resulted in exceedance of the airplane’s anti-icing system capabilities, a degradation of aircraft performance, and subsequent aerodynamic stall.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record CEN21FA198
Event ID
20210424102973
Case number
CEN21FA198
Dataset
full-current
Source SHA-256
5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
Source notes (4)
  • Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
  • Filled from the NTSB case API where the bulk record had no value: investigation status, coordinates, cause areas. Values present in the bulk record are kept.
  • The date is the local date, which is the same as the UTC date the NTSB stores.
  • API snapshot SHA-256: 5f9a51603f4bd7b0e66e9e2e54f3ad74dd842f68c9f45ddb8a85a89f2ea9ec3a; retrieved 2026-09-15T07:27:30.682Z.