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Viking Aviation Bell 407 accident

29 Sept 2016 · Lawton, OK, United States

Bell 407 · Accident: loss of control in flight during landing

From Lawton Fort Sill Regional Airport (LAW) to Lawton, OK

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Event

NTSB case
CEN16LA386
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
0 · 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
Charter & commuter
WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
Visual Meteorological Cond

Bell 407

Aircraft type
Bell 407
Category
Helicopter
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
N361SF
Onboard fatalities
Unknown
Route
From Lawton Fort Sill Regional Airport (LAW), Lawton, OKTo Lawton, OK
Aircraft age
About 15 years (built 2001)
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 135: Air Taxi & Commuter
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
Landing
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
Loss of control in flight
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

  • Personnel issues › Task performance

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

The commercial pilot of the helicopter was approaching to land on a helipad. It was his first landing to this helipad, though he had departed from the helipad the day before. Due to trees and transmission lines near the helipad, the pilot flew a slight right-turning, steep approach. When the helicopter was about 125 ft above the pad and 150 ft to the southwest of it, the pilot commanded left cyclic to stop the right turn. He estimated the helicopter to be 40 knots above effective transitional lift, and in a stable 500 ft per minute descent; there was a headwind. The helicopter did not respond to his control input, and the pilot announced to the crew his intention to go around. He increased left cyclic until the cyclic was against his left leg and the helicopter still did not respond. The pilot lost control of the helicopter and it landed hard, colliding with a wall.

Data extracted from the engine control unit (ECU) was consistent with the engine producing the required power and responding to collective control inputs; however, the data indicated that the main rotor speed and torque were exceeded. These exceedances suggested that a large demand for power was commanded by the pilot, likely during the go-around. Examination of the helicopter did not reveal any mechanical anomalies that would have precluded normal operation. The helicopter was in a right bank with 3 crewmembers seated on the right side of the helicopter, one crewmember seated on the left side, and was carrying a near-full fuel load. The distribution of crew members and a high torque setting may have contributed to the pilot's inability to maintain helicopter control; however, the extent to which these factors may have contributed could not be determined.

Probable cause

The pilot's loss of helicopter control during landing, which resulted in a hard landing and collision with a wall.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record CEN16LA386
Event ID
20160929X02931
Case number
CEN16LA386
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. 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: 7d3d74d09b8bba99f6c228f97a09cbbcdf2ed5552c3c273dabe208a7507fae08; retrieved 2026-09-16T04:19:54.215Z.