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WPR15FA072 · Bell 206 L4

31 Dec 2014 · Benson, AZ, United States

N57AW Bell 206 L4 · Accident: VFR encounter with IMC en route

From Glendale Municipal Airport (KGEU) to Sierra Vista Municipal Airport / Libby Army Air Field (KFHU)

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Event

NTSB case
WPR15FA072
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
2 · 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

Bell 206 L4

Aircraft type
Bell 206
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
N57AW
Operator
N57AW
Onboard fatalities
Unknown
Route
From Glendale Municipal Airport (KGEU), Glendale, AZTo Sierra Vista Municipal Airport / Libby Army Air Field (KFHU), Sierra Vista, AZ
Aircraft age
About 22 years (built 1992)
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
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
VFR encounter with IMC
DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
Destroyed

Cause areas

  • Environmental issues › Conditions/weather/phenomena
  • Personnel issues › Action/decision

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

NTSB narrative

The helicopter was on a visual flight rules (VFR) repositioning flight in preparation for providing contracted air support capability to the local sheriff's office the next day. The operator reported that the helicopter did not arrive at the intended destination, and the wreckage was located 29 miles north of the intended destination. The helicopter was fragmented into multiple pieces along a 174-ft debris path. Ground scars and wreckage distribution were consistent with collision with terrain while in forward flight. The observations from a weather station located 3 miles east-southeast of the accident site indicated ceilings less than 500 ft and visibility less than 1 mile were likely at the time of the accident. The relative humidity had rapidly increased above 90 percent immediately before the accident, which would be indicative of cloud cover and mist at or near the surface. Witnesses living in the local area reported that the visibility at ground level was very limited, with low clouds and fog. Observations near the destination showed lowered visibility and low ceilings as the rain moved eastward through the accident area. Gusty winds ahead of the lowering ceilings would have likely created low-level wind shear. The operator's flight data monitoring system indicated that the helicopter was flying along an interstate about 300 ft above ground level (agl), which decreased to about 200 ft agl, likely as the visibility was reduced. However, the last recorded points indicated that the helicopter had climbed to about 500 ft agl, and was no longer tracking the interstate. It is likely that the VFR flight encountered instrument meteorological conditions, and the pilot was trying to maneuver to an area with greater visibility when the helicopter collided with terrain.

Weather information available to the pilot before takeoff showed a cold front between the departure airport and destination, with forecasted low clouds, rain, ceilings below 600 ft, and gusty winds associated with that front. It was the pilot's responsibility to review the weather before all Part 91 flights; the chief pilot was not required to review the conditions with the pilot for such flights. Had the pilot conducted thorough preflight planning, he should have identified the deteriorating weather conditions and recognized that he could not complete the VFR flight.

Probable cause

The pilot’s continued visual flight into instrument meteorological conditions which resulted in an inflight collision with terrain. Contributing to the accident was the pilot’s inadequate preflight planning, during which he failed to identify forecasted deteriorating weather conditions along the route of flight.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record WPR15FA072
Event ID
20150101X15630
Case number
WPR15FA072
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: local date, investigation status. Values present in the bulk record are kept.
  • The date is the local date; the NTSB stores the UTC date 2015-01-01.
  • API snapshot SHA-256: bfb93340e520e6f34a32e53bca41767ceeb563f763e0851f93a072f2d55aec48; retrieved 2026-09-14T17:30:31.694Z.