SevenBar Aviation Agusta A109 E incident
Agusta A109 E · Incident: system/component malfunction/failure (non-power) en route
From ME15 · Blue Hill, ME to Northern Light Eastern Maine Medical Center Heliport (ME02)
Event
- NTSB case
- ENG20IA005
- 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
- Incident
- 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
- Charter & commuter
- 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
Agusta A109 E
- Aircraft type
- Agusta A109
- 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
- N901EM
- Operator
- SevenBar Aviation
- Onboard fatalities
- Unknown
- Route
- From ME15 · Blue Hill, METo Northern Light Eastern Maine Medical Center Heliport (ME02), Bangor, ME
- Aircraft age
- About 15 years (built 2004)
- 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 135: Air Taxi & Commuter
- 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
- 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
- System/component malfunction/failure (non-power)
- DamageDestroyed: beyond practical repair. Substantial: damage that affects the structure, performance or handling and normally needs major repair. Minor: less than that. Glossary
- Minor
Cause areas
- Aircraft › Aircraft propeller/rotor
Approximate · Coordinates from the NTSB case API, which marks them as estimated or does not say; no uncertainty radius is established.
NTSB narrative
The main rotor blade tip cap leading edge fractures initiated due to fatigue cracking with multiple initiation sites. At the time of the incident, the possibility of fatigue cracking of the leading edge of the P/N 709-0103-29-109 tip cap was a known issue, and Leonardo technical bulletin (bollettino tecnico, or BT) No. 109EP-85 and Federal Aviation Administration (FAA) airworthiness directive (AD) 2007-26-52 were previously issued to inspect for incipient cracks before they grew large enough to result in an inflight separation of the tip cap. These inspections primarily relied on visual inspection of the tip cap leading edge using magnification, and only required dye penetrant inspection of the leading edge if there are doubts about the presence of cracks or if damage other than a crack was found. It is possible that the fatigue crack on tip cap serial number L206 was present during its last inspection, but the visual inspection did not detect the presence of this crack. The crack on the tip cap leading edge remained undetected and propagated until the incident flight, when aerodynamic forces led to partial separation of the upper skin from the lower skin and core. While a visual inspection method can detect surface cracks, variances in the inspection environment (such as lighting), inspector experience, and operators’ maintenance practices can affect the success in detecting surface damage, such as a crack. After the initial issuance of BT No. 109EP-85 and FAA AD 2007-26-52, there continued to be a recurrence of partial and complete inflight separations of tip caps, with at least six known tip cap failures due to fatigue cracking. This indicates that reliance primarily on a visual inspection was not sufficient to eliminate the issue of detecting fatigue cracks before they resulted in a failure of the tip cap. A revision to BT No. 109EP-85 required dye penetrant inspection of the tip caps, which should provide a more reliable inspection method for identifying surface cracks.
Probable cause
Fatigue fracture of the main rotor blade tip cap leading edge and subsequent partial separation of the tip cap, resulting in increased vibrations in the main rotor.
Verbatim NTSB analysis and probable cause from the NTSB dataset
Sources
NTSB record ENG20IA005
- Event ID
- 20191122X42900
- Case number
- ENG20IA005
- 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, 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: e2fe3507e8017858c70877d787f222122e5bebdc282529cccc86ef43b9510eb9; retrieved 2026-09-16T10:40:17.922Z.