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 22, 1991 · Beech B200 · N770M
Greenbay, WI
Overview
Report Status
Probable Cause
Event Type
Incident
Date
July 22, 1991
Injury Outcomes
No injuries (8 uninjured)
Location
Greenbay, WI
Aircraft
Beech B200
Tail Number
N770M
Injuries
None
Aircraft Damage
Minor
NTSB Number
CHI91IA223
THE TWIN-ENGINE TURBO PROP AIRPLANE WAS CRUISING AT 8000' MSL, WHEN THE LEFT ENGINE'S OUTBOARD AFT UPPER ACCESSORY CASE COWL DOOR SEPARTED FROM ITS MOUNT. THE COWL DOOR STRUCK THE TOP SURFACE OF THE LEFT WING (OUTBOARD OF THE ENGINE NACELLE) & PENETRATED THE WING'S FUEL CELL. THIS RESULTED IN FUEL SIPHONING & PROMPTED THE PILOT TO PERFORM A PRECAUTIONARY ENGINE SHUTDOWN. THE AIRPLANE WAS LANDED WITHOUT FURTHER INCIDENT. AIRWORTHINESS DIRECTIVE (AD) 91-18-11 (EFFECTIVE 9/3/91) REQUIRED STRUCTURAL MODIFICATION OF THE AFT UPPER COWL ASSEMBLY DOORS TO PREVENT INFLIGHT SEPARATION.
NTSB Probable Cause
INADEQUATE AIRFRAME DESIGN, WHICH RESULTED IN THE IN-FLIGHT SEPARATION OF THE LEFT ENGINE'S OUTBOARD AFT UPPER COWL DOOR.
Full Narrative
THE TWIN-ENGINE TURBO PROP AIRPLANE WAS CRUISING AT 8000' MSL, WHEN THE LEFT ENGINE'S OUTBOARD AFT UPPER ACCESSORY CASE COWL DOOR SEPARTED FROM ITS MOUNT. THE COWL DOOR STRUCK THE TOP SURFACE OF THE LEFT WING (OUTBOARD OF THE ENGINE NACELLE) & PENETRATED THE WING'S FUEL CELL. THIS RESULTED IN FUEL SIPHONING & PROMPTED THE PILOT TO PERFORM A PRECAUTIONARY ENGINE SHUTDOWN. THE AIRPLANE WAS LANDED WITHOUT FURTHER INCIDENT. AIRWORTHINESS DIRECTIVE (AD) 91-18-11 (EFFECTIVE 9/3/91) REQUIRED STRUCTURAL MODIFICATION OF THE AFT UPPER COWL ASSEMBLY DOORS TO PREVENT INFLIGHT SEPARATION.
Flight
Event TypeIncident
Event Time09:05 CDT
Nearest Airport0nm N
Runway0
Flight Plan FiledIFR
Aircraft FireNo
Aircraft ExplosionNo
Aircraft
AircraftBeech B200
Tail NumberN770M
Aircraft CategoryAir
DamageMinor
Operating RulePart 91
Engines2
Engine TypeTurboprop
Engine DetailsP&W · PT6A-42 · Turboprop · 840
Seats8
People & Injuries
Injury SummaryNo injuries (8 uninjured)
Fatal0
Serious0
Minor0
Uninjured8
Total8
Crew 1Age 52 · Second Class
Conditions
ConditionsVMC
LightDaylight
Wind240° @ 7 kt
Visibility3 sm
CeilingBroken clouds 8000 ft
Temperature / Dew Point0 C / 0 C
Altimeter0
Observation Time13:50
Weather SourceWFAC