CHI03LA217 · Enstrom F-28C
Enstrom F-28C · Accident: rotor failure/malfunction en route
From Waverly Municipal Airport (C25) to Waverly Municipal Airport (C25)
Event
- NTSB case
- CHI03LA217
- 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
- Unknown
- 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
Enstrom F-28C
- Aircraft type
- Enstrom F-28
- 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
- N51699
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Waverly Municipal Airport (C25), Waverly, IATo Waverly Municipal Airport (C25)
- 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
- 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
- Rotor failure/malfunction
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Substantial
Cause areas
- Rotor system, main rotor tension torsion bar › Corroded
- Rotor system, main rotor tension torsion bar › Fatigue
- Rotor system, main rotor tension torsion bar › Separation
- Rotor system, main rotor › Other
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The helicopter sustained substantial damage when the main rotor blade impacted the tail boom during a forced landing. The helicopter experienced in-flight vibrations prior to the forced landing. The pilot stated that the helicopter experienced extreme vibration in-flight at 200 feet above ground level. He said that helicopter control was "10% to nil." An examination revealed that one of three Push-Pull Rod Assemblies, part number 28-16253-1, was found corroded and separated. The operator's fleet of aircraft was examined and four other control rods were found with corrosion. Examination of the rod with the separation from the accident helicopter at the National Transportation Safety Board's Materials Laboratory revealed that "most of the fracture areas were on a plane that was nearly perpendicular to the longitudinal axis of the rod, indicative of a brittle fracture mechanism such as fatigue cracking." The pilot stated, "Pitch control rod has no inspection procedure at this time. It rusted from inside and not visible from outside." Subsequent to the accident, Enstrom issued Service Directive Bulletin (SDB) No. 0096. The bulletin directs visual inspection of control rods with part number 28-16253-1 and 28-16253-101 according to their time in service on F-28A, F-28C, F-28F, 280, 280C, 280F, and 280FX helicopters.
Probable cause
The main rotor blade push-pull rods being corroded, sustaining fatigue, and separating in cruise and the main rotor blade contacting the tail boom during the emergency landing. Factors were the diminished aircraft control and the vibrations encountered during flight after the rod separation.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CHI03LA217
- Event ID
- 20030724X01188
- Case number
- CHI03LA217
- 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, coordinates. 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: 7a7aec7c7087830a599be92327a4433becaaaf5680c485c901ca3baeffa7af37; retrieved 2026-09-22T08:56:45.150Z.