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
April 20, 1991 · Robinson R22-BETA · N4066J
Phoenix, AZ
Overview
Report Status
Probable Cause
Event Type
Accident
Date
April 20, 1991
Injury Outcomes
2 injuries (1 serious injury, 1 minor injury)
Location
Phoenix, AZ
Aircraft
Robinson R22-BETA
Tail Number
N4066J
Operator
Avcon
Injuries
Serious
Aircraft Damage
Substantial
NTSB Number
LAX91LA182
THE INSTRUCTOR PILOT ENTERED AN AUTOROTATION WHILE IN CRUISE FLIGHT AT AN ALTITUDE OF 500 FEET ABOVE THE GROUND AND AT AN AIRSPEED OF 60 KNOTS. THE MAIN ROTOR TACHOMETER DECREASED BELOW ITS MINIMAL RANGE FOR FLIGHT WHEN THE HELICOPTER ENTERED THE AUTOROTATION. THE INSTRUCTOR PILOT CONTINUED THE AUTOROTATIVE DESCENT UNTIL PASSING 150 FEET ABOVE GROUND LEVEL BEFORE INITIATING A POWER RECOVERY. THE MAIN ROTOR RPM DID NOT INCREASE AND THE AIRCRAFT COLLIDED WITH GROUND.
NTSB Probable Cause
THE PILOT'S FAILURE TO MAINTAIN MAIN ROTOR RPM. FACTOR CONTRIBUTING TO THE ACCIDENT WAS THE PILOT'S INADEQUATE IN-FLIGHT PLANNING.
Full Narrative
THE INSTRUCTOR PILOT ENTERED AN AUTOROTATION WHILE IN CRUISE FLIGHT AT AN ALTITUDE OF 500 FEET ABOVE THE GROUND AND AT AN AIRSPEED OF 60 KNOTS. THE MAIN ROTOR TACHOMETER DECREASED BELOW ITS MINIMAL RANGE FOR FLIGHT WHEN THE HELICOPTER ENTERED THE AUTOROTATION. THE INSTRUCTOR PILOT CONTINUED THE AUTOROTATIVE DESCENT UNTIL PASSING 150 FEET ABOVE GROUND LEVEL BEFORE INITIATING A POWER RECOVERY. THE MAIN ROTOR RPM DID NOT INCREASE AND THE AIRCRAFT COLLIDED WITH GROUND.
Flight
Event TypeAccident
Event Time16:20 MST
Nearest Airport0nm N
Runway0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftRobinson R22-BETA
Tail NumberN4066J
Aircraft CategoryHeli
DamageSubstantial
OperatorAvcon
Operating RulePart 91
Engines1
Engine TypeReciprocating
Engine DetailsLycoming · O-320-B2C · Reciprocating · 131
Seats2
People & Injuries
Injury Summary2 injuries (1 serious injury, 1 minor injury)
Fatal0
Serious1
Minor1
Uninjured0
Total2
Crew 1Age 32 · First Class
Conditions
ConditionsVMC
LightDaylight
Wind260° @ 10 kt
Visibility40 sm
CeilingNone
Temperature / Dew Point34 C
Altimeter29.00 inHg
Observation Time21:49
Weather SourceWFAC