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Atlas / NTSB / GAA17CA436

NTSB CAROL · Event

Event GAA17CA436

2017-07-24 Toterville, Iowa, United States None 1 aircraft Status: Completed

Registry · N47AH

FAA Aircraft Registry record.

Make / Model

BELL 47G-3B

Year of manufacture

1961 · 56 years old at event

TCDS

2H3 · SCOTT'S-BELL 47 INC

Engine

LYCOMING TVO-435-GIA (280 hp)

Seats / Engines

3 seats · 1 engine

Last airworthiness date

19930421

ADS-B equipped

Yes — Mode-S A5BEC9

Registrant of record

SCOTTS HELICOPTER SERVICES INC

Source: FAA Aircraft Registry (releasable master file).

Aircraft involved

Probable cause & findings

The pilot’s failure to maintain rotor rpm while maneuvering at low altitude with low airspeed and a tailwind.

Factual narrative

According to the helicopter pilot, during an agricultural flight, he made a downwind turn to spray the intended field. During the low airspeed right turn, he increased the engine power and the rotor RPM decreased. He reported that he leveled the helicopter to clear powerline wires, but the rotor RPM remained low. The helicopter descended, and the pilot landed the helicopter in a corn field. The helicopter sustained substantial damage to the tailboom and the horizontal stabilizer. The nearest METAR was 15 nautical miles south-southeast and reported that about the time of the accident, the wind was calm. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation. According to the helicopter pilot, during an agricultural flight, he made a downwind turn to spray the intended field. During the low airspeed right turn, he increased the engine power, and the rotor rpm decreased. He reported that he leveled the helicopter to clear power lines, but the rotor rpm remained low. The helicopter descended, and the pilot landed the helicopter in a corn field. The helicopter sustained substantial damage to the tailboom and horizontal stabilizer. The nearest METAR located 15 nautical miles south-southeast from the accident site reported that, about the time of the accident, the wind was calm. The pilot reported that there were no preaccident mechanical malfunctions or failures with the helicopter that would have precluded normal operation. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12

NTSB Findings

Hierarchical cause / factor breakdown from the FAA bulk avdata database. Each finding tagged C (Cause) or F (Factor).

  • C Personnel issues-Task performance-Use of equip/info-Aircraft control-Pilot - C
  • C Environmental issues-Conditions/weather/phenomena-Wind-Tailwind-Effect on operation - C
  • C Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Prop/rotor parameters-Not attained/maintained - C
  • C Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Airspeed-Not attained/maintained - C
  • C Aircraft-Aircraft oper/perf/capability-Performance/control parameters-Altitude-Attain/maintain not possible - C

Verbatim from NTSB's published report. Source file NTSB_2017_GAA17CA436.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.