ATL89DKG06 · Bell UH-1B
Bell UH-1B · Accident: airframe, component or system failure en route
From Plains, GA to Marion County Airport (82A)
Event
- NTSB case
- ATL89DKG06
- Event typeAccident: someone killed or seriously injured, or the aircraft substantially damaged (NTSB definition). Incident: an occurrence that affected or could have affected safety, short of that. Glossary
- Accident
- InvestigationHow far the investigation had got when the record was published: preliminary, ongoing, final or completed. Unknown where the source does not say. Glossary
- Completed
- API-reported fatalities
- 2 · all aircraft and ground
- Ground fatalities
- 0
- OperationWhat kind of flying it was, grouped by the rules it flew under: airline (US Part 121), air taxi and commuter (Part 135), general aviation (Part 91 and similar), military or government. Glossary
- General aviation
- WeatherVisual meteorological conditions (VMC): good enough to fly by looking outside. Instrument conditions (IMC): cloud or low visibility, flying by instruments. Glossary
- Visual Meteorological Cond
Bell UH-1B
- Aircraft type
- Bell UH-1
- Category
- Helicopter
- RegistrationThe aircraft's tail number, such as N12345 or G-ABCD. Registrations are reissued, so the same one years apart can be a different aircraft. Glossary
- N840MC
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Plains, GATo Marion County Airport (82A), Buena Vista, GA
- Aircraft age
- Not recorded
- Flight rulesThe regulations the flight operated under: in the US, Part 91 (general aviation), Part 121 (airlines), Part 135 (air taxi and commuter) and others; for flights abroad, the NTSB's coarser commercial or non-commercial code. Glossary
- Part 137: Agricultural
- Phase of flightThe stage of the flight when things started to go wrong: standing, taxi, takeoff, initial climb, en route, maneuvering, approach or landing. Glossary
- En route · cruise
- First occurrenceThe single coded event the NTSB judges best describes what happened (records from 2008 on). Older records name the first occurrence in the sequence instead. Glossary
- Airframe, component or system failure
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Destroyed
Cause areas
- Aerial application equipment › Failure, total
- Aerial application equipment › Improper
- Company/operator management › Maintenance, modification, improper
- Rotor drive system, main rotor mast(drive shaft) › Failure, total
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
DURING A POSITIONING FLT, AN IN-FLIGHT BREAKUP OF THE HELICOPTER OCCURRED IN THE VICINITY OF WHERE IT WAS CROSSING A LINE OF TREES BETWEEN 2 CLEARED AREAS. WRECKAGE WAS FOUND SCATTERED OVER AN AREA OF APRX 300 YDS IN LENGTH, ALONG A HEADING OF 340 DEG. AT THE SE END, PIECES WERE FOUND FROM THE LEFT SPRAY BOOM & MAIN ROTOR AERODYNAMIC FAIRING. FURTHER TO THE NW, VARIOUS PARTS WERE FOUND FROM THE LEFT SIDE OF THE HELICOPTER, LEFT SPRAY BOOM & TAIL ROTOR. THE MAIN ROTOR & MAIN ROTOR HUB WERE FOUND ABOUT 120 YDS TO THE RIGHT OF THE WRECKAGE PATH. THE FUSELAGE, ENG & TRANS- MISSION WERE FOUND ABOUT 240 YDS NW OF THE 1ST PART OF THE WRECKAGE. AN EXAM OF THE WRECKAGE REVEALED THE MAIN ROTOR SYSTEM HAD SEPARATED DUE TO MAST BUMPING. THERE WAS EVIDENCE THE LEFT SPRAY BOOM HAD CONTACTED THE MAIN ROTOR BLADES DURING FLT. ALL OF THE FRACTURES OF THE SPRAY BOOM, STEEL TRUSS & ASSOC LUGS INDCD OVERLOAD FAILURE IN AFT & UPWARD DRCTN. THE SPRAY ASSEMBLY & BOOM HAD NOT BEEN INSTALLED IN ACCORDANCE WITH FAR PART 23.
Probable cause
IMPROPER MODIFICATION OF THE HELICOPTER BY THE COMPANY/OPERATOR, AND FAILURE OF THE SPRAY BOOM, WHICH RESULTED IN MAST BUMPING, AND SUBSEQUENT FAILURE OF THE MAIN ROTOR ASSEMBLY.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ATL89DKG06
- Event ID
- 20001213X29290
- Case number
- ATL89DKG06
- Dataset
- historical-pre2008
- Source SHA-256
- 89e2df6d848e7ab3b42e7d7c7a03ff403303057a26ca04c95b3ea67201c3ce74
Source notes (4)
- Unreviewed is an editorial label, not an investigation status. API-sourced is not report-checked or human-reviewed. Explicit event totals are used without summing aircraft injury tables; onboard allocation is withheld. Unknown values remain unknown. The operation category is mapped from the NTSB-reported FAR part and has not been reviewed.
- Filled from the NTSB case API where the bulk record had no value: investigation status. Values present in the bulk record are kept.
- The date is the local date, which is the same as the UTC date the NTSB stores.
- API snapshot SHA-256: 8e8b31c9e34ea025cc0b0b74d3103a240ef353ce434a063bdd93715183b87c2a; retrieved 2026-09-21T03:08:11.429Z.