CEN18LA313 · Brantly B-2 A
Brantly B-2 A · Accident: part(s) separation from aircraft while maneuvering
From Jack Barstow Airport (IKW) to Jack Barstow Airport (IKW)
Event
- NTSB case
- CEN18LA313
- 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
Brantly B-2 A
- Aircraft type
- Brantly B-2
- 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
- N5901X
- Operator
- Unknown
- Onboard fatalities
- Unknown
- Route
- From Jack Barstow Airport (IKW), Midland, MITo Jack Barstow Airport (IKW), Midland, MI
- Aircraft age
- About 58 years (built 1960)
- 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
- Maneuvering
- Defining eventThe 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
- Part(s) separation from aircraft
- 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
- Aircraft › Aircraft oper/perf/capability
- Aircraft › Aircraft propeller/rotor
Approximate · Coordinates as recorded by the NTSB; no uncertainty radius is established.
NTSB narrative
After departing from the airport, the helicopter was in a level flight profile about 2,000 ft above ground level, about 1/4 mile south of the airport. The pilot stated that, when the helicopter was about 60 kts and on a heading of about 270°, he felt a "strong flutter" emit from the helicopter and heard a subsequent "bang" from the rear of the helicopter. The helicopter immediately turned 180° to the right, and the pilot reduced collective and maintained control of the helicopter. The pilot increased the airspeed and maneuvered the helicopter for an emergency landing to the departure airport. During the landing sequence, the helicopter experienced a dynamic rollover and impacted terrain.
A postaccident examination revealed that one of the tail rotor blades fractured and separated at the spar. Further, one of the bosses of the tail rotor hub fractured from fatigue. The fatigue crack initiated at multiple sites near the shoulder of the hub shank. These smaller cracks coalesced and propagated inward through over half the hub cross-section. During this propagation, as reverse bending stresses increased, a series of smaller fatigue cracks initiated on the opposite surface, coalescing and propagating inward. When the cracked hub could no longer withstand the stress, the remaining cross-section fractured from overstress. The tail rotor blade affixed to this portion of the hub liberated when the final fracture of the hub boss occurred.
Probable cause
The in-flight separation of the tail rotor blade due to fatigue, which resulted in the subsequent emergency landing and dynamic rollover.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record CEN18LA313
- Event ID
- 20180804X55436
- Case number
- CEN18LA313
- Dataset
- full-current
- Source SHA-256
- 5cf380f0061817c0331a6b2d8cc7e0ee3a79bea469a1001dc5c10e56f35f5ab3
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: b3bca66bacc106102fa1ac9fd387df7927bc86fae7b566a233473f48b3e55136; retrieved 2026-09-16T08:02:55.351Z.