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CHI94LA175 · Hughes 269B

25 May 1994 · Toulon, IL, United States

Hughes 269B · Accident: airframe, component or system failure during takeoff

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Event

NTSB case
CHI94LA175
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
0 · 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

Hughes 269B

Aircraft type
Hughes 269
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
N9375S
Onboard fatalities
Unknown
Route
From not recordedTo not recorded
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 91: General Aviation
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
Takeoff
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

  • Other maintenance personnel › Maintenance, overhaul, improper

Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.

NTSB narrative

THE HELICOPTER HAD BEEN REASSEMBLED AFTER AN ANNUAL INSPECTION, WITH INSTALLATION OF 3 OVERHAULED MAIN ROTOR BLADES. THE MAIN ROTOR BLADE DAMPERS HAD BEEN DISASSEMBLED, INSPECTED AND REASSEMBLED. DURING REASSEMBLY, THE INTERNAL SEQUENCE OF FRICTION DISCS WAS INCORRECT, RESULTING IN IMPROPER AND NON- UNIFORM DAMPING ACTION BETWEEN THE BLADES. THE SHOCK STRUT OLEOS WERE NOT SERVICED. POST ACCIDENT INSPECTION REVEALED LOW PRESSURE IN THE 3 REMAINING INTACT STRUTS. DURING THE FIRST TAKEOFF AFTER REASSEMBLY TO TRACK THE MAIN ROTOR BLADES IN A HOVER, THE HELICOPTER ENCOUNTERED GROUND RESONANCE AND WAS DESTROYED.

Probable cause

the improper reassembly of the main rotor blade dampers and the underservicing of the landing gear skid hydraulic struts which resulted in ground resonance of the helicopter when the first takeoff after reassembly was attempted.

Verbatim NTSB analysis and probable cause from the NTSB dataset

Sources

NTSB record CHI94LA175
Event ID
20001206X01253
Case number
CHI94LA175
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: 318fe6a1f0cb767e48daf04c3b48b7b794c761a0f79aacf3086b4121f3ed87a4; retrieved 2026-09-21T22:37:54.273Z.