Overall Trends
Total, fatal, and serious accidents in the selected range.
Premium research interface
The modern interface for aviation safety intelligence.
Search investigations, review source evidence, monitor watched reports, and trace long-term patterns from one calm, data-first workspace.
63k+
Reports indexed
1940-2026
Coverage
Recent
Last data refresh
Search everything
Fast key and full-text search with live filters, watches, and precise metadata.
Use quotes for exact phrase matches (for example "fuel selector valve").
Featured Report
Safety trends by operating rule
Track fatal and non-fatal accident patterns across Part 91, Part 135, and Part 121 operations.
Loading trend charts…
High-signal investigations
Major cases, deep-report coverage, and investigation media across decades of NTSB history.
Browse the aviation graph
Move quickly by aircraft, airport, operator, and time with indexes built for research, not wandering.
Last Data Update
By Decade
By Month
Aircraft Manufacturer
More manufacturersAirports
More airportsOperators
More operatorsAbout
Aviation safety reports, made easier to study
NTSB Reports is an independent research and search tool for public aviation accident and incident records. It brings NTSB aviation reports, structured fields, docket files, extracted figures, photos, videos, and update history into one searchable interface.
The goal is practical safety education: make it faster to find relevant investigations, compare similar events, review factual records, and understand the evidence behind probable-cause and preliminary reports.
The investigative work and source records belong to the National Transportation Safety Board and the published investigation record. This site is not affiliated with or endorsed by the NTSB.
FAQs
NTSB Report
August 14, 1990 · Bell 47 D-1 · N3656F
Stockbridge, MI
Overview
Report Status
Probable Cause
Event Type
Accident
Date
August 14, 1990
Injury Outcomes
1 injury (1 serious injury)
Location
Stockbridge, MI
Aircraft
Bell 47 D-1
Tail Number
N3656F
Operator
Allied Helicopter Service
Injuries
Serious
Aircraft Damage
Destroyed
NTSB Number
CHI90DEC04
THE AGRICULTURAL HEILCOPTER HAD JUST TAKEN OFF ON AN EARLY MORNING RE-POSITIONING FLIGHT WHEN THE CANOPY BECAME COMPLETELY FOGGED OVER. BEFORE THE PILOT COULD RE-ORIENT HIMSELF BY LOOKING OUT THE SIDE OPENING, THE HELICOPTER COLLIDED WITH A POWER POLE AND WIRES. THE COLLISION CAUSED THE FUEL TANK TO RUPTURE AND SPRAYED AVIATION FUEL ONTO THE HOT ENGINE AND EXHAUST PIPES. THE ENSUING FIRE DESTROYED THE HELICOPTER.
NTSB Probable Cause
THE RESTRICTED VISUAL LOOKOUT WHICH RESULTED FROM THE CANOPY FOGGING UP.
Full Narrative
THE AGRICULTURAL HEILCOPTER HAD JUST TAKEN OFF ON AN EARLY MORNING RE-POSITIONING FLIGHT WHEN THE CANOPY BECAME COMPLETELY FOGGED OVER. BEFORE THE PILOT COULD RE-ORIENT HIMSELF BY LOOKING OUT THE SIDE OPENING, THE HELICOPTER COLLIDED WITH A POWER POLE AND WIRES. THE COLLISION CAUSED THE FUEL TANK TO RUPTURE AND SPRAYED AVIATION FUEL ONTO THE HOT ENGINE AND EXHAUST PIPES. THE ENSUING FIRE DESTROYED THE HELICOPTER.
Flight
Event TypeAccident
Event Time05:54 EDT
Nearest Airport0nm N
Runway0
Flight Plan FiledNone
Aircraft FireIflt
Aircraft ExplosionNo
Aircraft
AircraftBell 47 D-1
Tail NumberN3656F
Aircraft CategoryHeli
DamageDestroyed
OperatorAllied Helicopter Service
Operating RulePart 91
Engines1
Engine TypeReciprocating
Engine DetailsFranklin · 6V4200-C32 · Reciprocating · 200
Seats2
People & Injuries
Injury Summary1 injury (1 serious injury)
Fatal0
Serious1
Minor0
Uninjured0
Total1
Crew 1Age 54 · Second Class
Conditions
ConditionsIMC
LightDawn
WindCalm
Visibility1 sm
CeilingNone
Temperature / Dew Point50 / 50
Altimeter29.00 inHg
Observation Time09:53
Weather SourceWFAC