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
June 4, 1994 · Bell 47H-1 · N2831B
Tulsa, OK
Overview
Report Status
Final with probable cause
Event Type
Accident
Date
June 4, 1994
Injury Outcomes
No injuries (2 uninjured)
Location
Tulsa, OK
Aircraft
Bell 47H-1
Tail Number
N2831B
Operator
Helio Brothers
Injuries
None
Aircraft Damage
Substantial
NTSB Number
FTW94LA193
A HELICOPTER PRIVATE PILOT LANDED HARD DURING THE SIXTH PRACTICE AUTOROTATION OF THE DAY. THE LANDING FLARE WAS DELAYED AND THE MAIN ROTOR RPM DECAYED TO THE POINT THAT DURING TOUCHDOWN, THE MAIN ROTOR BLADES FLEXED DOWN AND IMPACTED THE TAILBOOM.
NTSB Probable Cause
THE PILOT'S FAILURE TO MAINTAIN ROTOR RPM, HIS DELAYED LANDING FLARE, AND THE IMPROPER TOUCHDOWN.
Full Narrative
On June 4, 1994, at 0900 central daylight time, a Bell 47H-1 helicopter, N2831B, was substantially damaged while landing near Tulsa, Oklahoma. The private pilot and his pilot rated passenger were not injured. Visual meteorological conditions prevailed for the personal flight. The pilot told the Federal Aviation Administration (FAA) inspector that during the sixth practice autorotation being performed to an open field adjacent to the Downtown Airport, the rotor RPM decayed and the helicopter landed hard. The main rotor blades flexed down and chopped the tailboom.
Flight
Event TypeAccident
Event Time09:00 CDT
Nearest Airport0nm
Runway0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftBell 47H-1
Tail NumberN2831B
Aircraft CategoryHeli
DamageSubstantial
OperatorHelio Brothers
Operating RulePart 91
Engines1
Engine TypeReciprocating
Engine DetailsFranklin · 6V-350A · Reciprocating · 235
Seats2
People & Injuries
Injury SummaryNo injuries (2 uninjured)
Fatal0
Serious0
Minor0
Uninjured2
Total2
Crew 1Age 47 · Third Class
Conditions
ConditionsVMC
LightDaylight
WindCalm
Visibility10 sm
CeilingNone
Temperature / Dew Point64 F / 0 C
Altimeter0
Weather SourcePILO