Pilot Debrief

PIPER PA-18-150 near Thurlow, MT — 2024-05-14

Final reportWPR24FA150
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Date
2024-05-14
Location
Thurlow, MT, USA
Aircraft
PIPER PA-18-150
Registration
UNREG
Category
Airplane
Highest injury
Fatal
Fatalities
2

Probable cause

The pilot’s exceedance of the airplane’s critical angle of attack while maneuvering at low altitude, resulting in an aerodynamic stall and subsequent impact with terrain. Contributing to the accident was the pilot’s distraction by his cell phone use while maneuvering.

Contributing factors

Contributing to the accident was the pilot’s distraction by his cell phone use while maneuvering.

NTSB narrative

The pilot of the tandem seat, non-registered airplane and a passenger were conducting a predator control flight that targeted coyotes on private land. A wildlife control officer on the ground near the designated hunting area was communicating with the pilot via through cell phone and could hear gunfire when the call ended. The control officer attempted to call the pilot back after he expected the flight to have ended but did not determine a need to search for the airplane. A ranch hand located the wreckage later in the day. GPS data recovered from a handheld device found in the airplane wreckage showed that most of the flight was conducted at low altitudes. While engaging wildlife targets, the pilot slowed the airplane to as low as 36 kts groundspeed and performed multiple turns. During the last period of circling maneuvers the airplane slowed to about 25 kts groundspeed while about 113 ft above ground level (agl). The manufacturer’s Pilot’s Operating Handbook for a similar model of airplane indicated that the stall airspeed was 43 mph (37 kts). Examination of the wreckage revealed the airplane impacted terrain in a nearly vertical, nose-down attitude while rotating clockwise. The wreckage signatures and very small debris area were consistent with an aerodynamic stall/spin. While maneuvering at low altitudes and low airspeed, the pilot likely exceeded the airplane’s critical angle of attack, which resulted in an aerodynamic stall/spin at an altitude too low for recovery. The pilot’s use of his cell phone, even with the aid of a hands-free device, likely distracted him from piloting duties. The pilot’s toxicological testing revealed medications that had the potential to cause performance impairment and other medications that were commonly used to treat cold and allergy symptoms; however, toxicological testing did not establish that the pilot was impaired by the medication, nor that he was experiencing cold or allergy symptoms at the time of the accident.

NTSB coding

Evidence available

  • ADS-B / radar
  • Photos
  • 15 docket documents
View NTSB final reportView NTSB docket

Docket documents15

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