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
July 4, 1991 · Jerrell RV-4 · N44AZ
Yellowstonepark, WY
Overview
Report Status
Probable Cause
Event Type
Accident
Date
July 4, 1991
Injury Outcomes
2 injuries (1 fatality, 1 minor injury)
Location
Yellowstonepark, WY
Aircraft
Jerrell RV-4
Tail Number
N44AZ
Operator
Donald a Jerrell
Injuries
Fatal
Aircraft Damage
Substantial
NTSB Number
SEA91LA154
THE PILOT OF THE RV-4 EXPERIMENTAL AIRCRAFT EXPERIENCED A PARTIAL POWER LOSS, AND RECEIVED FATAL INJURIES WHEN THE AIRCRAFT IMPACTED THE WATER, DURING AN ATTEMPTED EMERGENCY LANDING, NEAR THE SHORELINE OF A LAKE. LATER INSPECTION OF THE ENGINE FOUND THAT THE SCAT TUBING WHICH RAN FROM THE AIR INTAKE FILTER TO THE FUEL INJECTOR BODY, WAS ROUTED IN A MANNER THAT CAUSED THE INTERNAL WIRE SUPPORT TO BE DISPLACED, ALLOWING THE TUBING WALLS TO COLLAPSE. THIS CONDITION REDUCED THE INDUCTION AIRFLOW TO THE ENGINE.
NTSB Probable Cause
A COLLAPSED INDUCTION AIR DUCT. FACTORS INCLUDE INADEQUATE DESIGN BY THE MANUFACTURER/BUILDER, AND A MISJUDGED RATE OF DESCENT BY THE PILOT.
Full Narrative
THE PILOT OF THE RV-4 EXPERIMENTAL AIRCRAFT EXPERIENCED A PARTIAL POWER LOSS, AND RECEIVED FATAL INJURIES WHEN THE AIRCRAFT IMPACTED THE WATER, DURING AN ATTEMPTED EMERGENCY LANDING, NEAR THE SHORELINE OF A LAKE. LATER INSPECTION OF THE ENGINE FOUND THAT THE SCAT TUBING WHICH RAN FROM THE AIR INTAKE FILTER TO THE FUEL INJECTOR BODY, WAS ROUTED IN A MANNER THAT CAUSED THE INTERNAL WIRE SUPPORT TO BE DISPLACED, ALLOWING THE TUBING WALLS TO COLLAPSE. THIS CONDITION REDUCED THE INDUCTION AIRFLOW TO THE ENGINE.
Flight
Event TypeAccident
Event Time09:00 MDT
Nearest Airport0nm N
Runway0
Flight Plan FiledNone
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftJerrell RV-4
Tail NumberN44AZ
Aircraft CategoryAir
DamageSubstantial
OperatorDonald a Jerrell
Operating RulePart 91
Engines1
Engine TypeReciprocating
Engine DetailsLycoming · IO-320-E3D · Reciprocating · 150
Seats2
People & Injuries
Injury Summary2 injuries (1 fatality, 1 minor injury)
Fatal1
Serious0
Minor1
Uninjured0
Total2
Crew 1Age 43 · Second Class
Conditions
ConditionsVMC
LightDaylight
WindCalm
Visibility20 sm
CeilingNone
Temperature / Dew Point0 C / 0 C
Altimeter0
Weather SourceWIT