# NTSB ERA12LA379: Bell 427, N427AL, Indiantown, FL, June 4, 2012

- Type: NTSB accident investigation
- Classification: Accident · Minor injuries · Limited investigation · Final report
- Date: June 4, 2012, 09:55 local (13:55 UTC)
- Place: Indiantown, FL
- Coordinates: 27.031389, -80.35083 (estimated)
- Nearby events: https://openairdocs.org/map.md?lat=27.0314&lon=-80.3508&mi=10
- Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping)
- Defining event: [Enroute-cruise: Birdstrike](https://openairdocs.org/ntsb-events/901)
- Highest injury: Minor injuries
- Injuries: 5 minor
- Status: Completed, report September 5, 2013
- Report: Approved by Office Director
- NTSB office: Eastern Region Aviation
- Parties: FAA/FSDO
- NTSB case key (mKey): 83847
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA12LA379
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/83847/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=83847
- Page: https://openairdocs.org/ntsb/ERA12LA379

## Probable cause

The inflight collision with birds, resulting in damage to the rotor head assembly and a subsequent forced landing and rollover.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Main rotor system: main rotor blade system](https://openairdocs.org/ntsb-findings/01046210): Aircraft › Aircraft propeller/rotor · Damaged/degraded (probable cause); cases with it: [Bell 427, 1 case](https://openairdocs.org/ntsb-findings/01046210/cases.md?model=1182207), [All aircraft, 60 cases](https://openairdocs.org/ntsb-findings/01046210/cases.md)
- [Object/animal/substance: animal(s)/bird(s)](https://openairdocs.org/ntsb-findings/03022045): Environmental issues › Physical environment · Contributed to outcome (probable cause); cases with it: [Bell 427, 1 case](https://openairdocs.org/ntsb-findings/03022045/cases.md?model=1182207), [All aircraft, 358 cases](https://openairdocs.org/ntsb-findings/03022045/cases.md)

## Sequence of events

The events NTSB coded, in order, by phase of flight. The defining event best describes what happened.

- [Enroute-cruise: Birdstrike](https://openairdocs.org/ntsb-events/901) (defining event); cases with it: [Bell 427, 1 case](https://openairdocs.org/ntsb-events/901/sequence.md?model=1182207), [All aircraft, 253 cases](https://openairdocs.org/ntsb-events/901/sequence.md)
- [Enroute-cruise: Flight control sys malf/fail](https://openairdocs.org/ntsb-events/333); cases with it: [Bell 427, 1 case](https://openairdocs.org/ntsb-events/333/sequence.md?model=1182207), [All aircraft, 410 cases](https://openairdocs.org/ntsb-events/333/sequence.md)
- [Emergency descent: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Bell 427, 1 case](https://openairdocs.org/ntsb-events/440/sequence.md?model=1182207), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md)
- [Landing-flare/touchdown: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Bell 427, 1 case](https://openairdocs.org/ntsb-events/092/sequence.md?model=1182207), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md)
- [Landing-flare/touchdown: Roll over](https://openairdocs.org/ntsb-events/097); cases with it: [Bell 427, 1 case](https://openairdocs.org/ntsb-events/097/sequence.md?model=1182207), [All aircraft, 261 cases](https://openairdocs.org/ntsb-events/097/sequence.md)

## Analysis

The pilot reported that, about 25 minutes into the flight, he maneuvered the helicopter to avoid large birds. The pilot felt something impact the upper right side of the helicopter near the main rotor mast area. The helicopter began shaking violently and became difficult to control. He immediately decided to abort the flight. During the landing attempt, helicopter control was lost; the helicopter entered a left spin, impacted the ground, and rolled over. The main and tail rotor systems and the fuselage sustained substantial damage. The immediate decision to abort the flight after impact with the birds most likely aided the pilot in executing an emergency landing. Evidence of bird remains were present on components of the rotor head, two of the four pitch change rods, and the tail rotor. Both pitch change rods with bird remains were separated from one of their attach points. The bird remains were removed and sent to the Smithsonian Institute for identification. According to the report, male and female Black Vulture DNA was found on the pitch control rods, pitch control linkages, and the tail rotor. Examination of the rotor head parts found two pitch change links failed in tensile overstress; one of these exhibited an inward bending that could have been caused by a bird strike. The damage to the other pitch change link was most likely caused by the dynamic rollover as the rotor blades impacted the ground or other helicopter components. The accident sequence most likely initiated when the birds struck the pitch change rods.

## Factual narrative

On June 4, 2012, about 0955 eastern daylight time, a Bell 427, N427AL, sustained substantial damage after an inflight bird strike, main rotor vibration, and hard landing near Indiantown, Florida. The private pilot, commercial copilot, and three passengers received minor injuries. The helicopter was registered to Southern Aviation Systems, LLC, and operated by a private individual. Visual meteorological conditions prevailed and no flight plan was filed for the 14 Code of Federal Regulations Part 91, executive/corporate flight, destined for Ocala International Airport-Jim Taylor Field (KOCF) Ocala, Florida. The flight originated from the Palm Beach International Airport (PBI), West Palm Beach, Florida, about 0930. According to the pilot, approximately 25 minutes into the flight, while on a heading of 330 degrees and at an altitude of 800 feet mean sea level (msl), he maneuvered the helicopter to avoid colliding with several large birds. The pilot felt something impact the upper right side of the helicopter near the main rotor mast area. Immediately following the impact, the helicopter started shaking violently, and became difficult to control. The pilot elected to land in an open field. Descending through 300 feet msl, the shaking became more pronounced and the helicopter became uncontrollable. At 50 feet msl, the aircraft went into a left spin and impacted the ground and rolled over on its left side. All onboard were able to exit the helicopter on their own. Examination of the helicopter by a FAA inspector and a representative of the airframe manufacturer revealed that the tail boom separated about three feet aft of the attachment point to the fuselage. The collapse of the left mail landing gear and subsequent tail boom departure from the airframe was consistent with a dynamic rollover by the helicopter. Pitch change links connected the swash plate at the lower end to the main rotor blade pitch horns at the upper end. According to a NTSB metallurgy laboratory report, the orange square and red triangle-coded links were fractured approximately 1.25 inches from the end closest to the pitch horns where the tube was internally threaded. The fracture surfaces were oriented approximately 45 degree to the longitudinal axis of the tube and had a rough appearance, consistent with tensile overstress fractures. The orange tube had an inward dent approximately 0.75 inch below the fracture. The rod ends that connected the blue diamond and green circle-coded links to the swash plate were bent forward in the direction of rotation (clockwise direction as viewed beneath the mast looking up) and fractured in the thread roots. The fracture surfaces had a rough irregular appearance. The deformation and appearance of the fracture surfaces were consistent with bending overstress fracture. The main rotor blade pitch horns were fractured and twisted on the blue diamond and green circle-coded blades. The ends of the pitch horns were still connected to the upper fittingsof the pitch links. The fracture surfaces were at approximately 45° angles to the longitudinal axis of the arm and they had a rough appearance, consistent with an overstress fracture. All four main rotor blades separated from the hub due to contact with the ground or other helicopter components. Ground scars by the main rotor blades were verified through paint marks and gouges in the dirt. Evidence of bird remains were present on components of the rotor head, two of the four pitch change rods, and the tail rotor. Each pitch change rod with bird remains was separated from one of their attach points respectively. The bird remains were removed and sent to the Smithsonian Institute for bird identification. According to the report, male and female Black Vulture DNA was found on the pitch control rods, pitch control linkages, and the tail rotor.

## Aircraft

- Registration: [N427AL](https://openairdocs.org/deregistered/N427AL-2012-10-18), registration cancelled 2012-10-18, S/N 56018 (OpenAirDocs)
- Reported make and model: BELL 427
- Registry model: [Bell 427](https://openairdocs.org/model/bell-427) (registry code 1182207) (OpenAirDocs)
- Category: Helicopter
- Serial number: 56018
- Airframe hours: 1345
- Engines: turbo shaft; Pratt & Whitney PW207D 572 horsepower turbo shaft
- Damage: Substantial damage
- Flight: Executive/Corporate, Part 91
- Airworthiness certificate: Standard, Normal
- Last inspection: Annual, May 7, 2012, 15 hours before
- Departed: PBI, Palm Beach, FL
- Destination: OCF, Ocala, FL
- Flight plan: Company VFR

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 60; injuries: minor; private; medical: class 2, with waivers/limitations; last flight review February 15, 2011; seat: right; flight hours: 2,132 total, 427 in this make and model, 25 in the last 90 days
- Other flight crew; age 42; injuries: minor; commercial; airplane ratings: single-engine land; instrument ratings: airplane, helicopter; medical: class 2, with waivers/limitations; last flight review February 3, 2011; seat: left; flight hours: 4,000 total, 427 in this make and model

## Weather

- Conditions: Visual (VMC), Day
- Wind: 260° at 12 knots
- Visibility: 7 statute miles
- Lowest ceiling: none
- Temperature: 84 °F, dew point 73 °F
- Altimeter: 29.96 inHg
- Observed at: SUA, 13 nm away

## FAA reports on this event (1)

The FAA's own accident and incident reports, matched to the aircraft by N-number and date (OpenAirDocs).

- [Accident 20120604011249A](https://openairdocs.org/incident/20120604011249A), Jun 4, 2012: Bell 427, Indiantown, FL, Substantial damage. N427AL appears to have struck a large bird in the helicopters rotor system at an altitude of approximately 800'. The pilot's reported that the helicopter…

## Docket (16 files)

The files NTSB released with the investigation on July 9, 2013, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=83847. 17.2 MB in all.

- Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 496 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40395892&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF
- Evidence Control Form. (FAA) (item 2, .PDF, 118 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40392413&FileExtension=.PDF&FileName=Evidence%20Control%20Form.%20(FAA)-Redacted.PDF
- Materials Laboratory 15 - Factual Report 12-108 (with 1 embedded image) (item 3, .PDF, 136 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40377528&FileExtension=.PDF&FileName=Materials%20Laboratory%2015%20-%20Factual%20Report%2012-108%20(with%201%20embedded%20image)-Master.PDF
- Witness Statement (item 4, .PDF, 51 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40392411&FileExtension=.PDF&FileName=Witness%20Statement-Master.PDF
- Wreckage Diagram. (Courtesy of FAA) (item 5, .PDF, 140 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40392414&FileExtension=.PDF&FileName=Wreckage%20Diagram.%20(Courtesy%20of%20FAA)-Master.PDF
- NVM 18 - Attachment 1 - PWC Download Report (item 6, .PDF, 91 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40382689&FileExtension=.PDF&FileName=NVM%2018%20-%20Attachment%201%20-%20PWC%20Download%20Report-Master.PDF
- GPS 17 - Specialist's Factual Report (item 7, .PDF, 59 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40382698&FileExtension=.PDF&FileName=GPS%2017%20-%20Specialist%27s%20Factual%20Report-Master.PDF
- NVM 18 - Specialist's Factual Report (item 8, .PDF, 576 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40382699&FileExtension=.PDF&FileName=NVM%2018%20-%20Specialist%27s%20Factual%20Report-Master.PDF
- Maintenance Record Excerpts. (item 9, .PDF, 356 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40392405&FileExtension=.PDF&FileName=Maintenance%20Record%20Excerpts.-Redacted.PDF
- Wreckage Release. (item 10, .PDF, 53 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40392412&FileExtension=.PDF&FileName=Wreckage%20Release.-Redacted.PDF
- Other Pertinent Forms and Reports (item 11, .PDF, 102 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40392482&FileExtension=.PDF&FileName=Other%20Pertinent%20Forms%20and%20Reports-Redacted.PDF
- Photo 1: Bird remains present on the Blue Diamond Blade. (Courtesy of FAA) (item 12, .PDF, 4.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40392429&FileExtension=.PDF&FileName=Photo%201%3A%20Bird%20remains%20present%20on%20the%20Blue%20Diamond%20Blade.%20(Courtesy%20of%20FAA)-Master.PDF
- Photo 2: Bird remains present on the green circle blade. (Courtesy of FAA) (item 13, .PDF, 3.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40392430&FileExtension=.PDF&FileName=Photo%202%3A%20Bird%20remains%20present%20on%20the%20green%20circle%20blade.%20(Courtesy%20of%20FAA)-Master.PDF
- Photo 3: Overview of fuselage and tail. (Courtesy of FAA) (item 14, .PDF, 4.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40392431&FileExtension=.PDF&FileName=Photo%203%3A%20Overview%20of%20fuselage%20and%20tail.%20(Courtesy%20of%20FAA)-Master.PDF
- Photo 4: #1 Pitch control link with hair samples attached. (Courtesy of FAA) (item 15, .PDF, 2.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40392433&FileExtension=.PDF&FileName=Photo%204%3A%20%231%20Pitch%20control%20link%20with%20hair%20samples%20attached.%20(Courtesy%20of%20FAA)-Master.PDF
- Photo 5: Rotor head and pitch link damage. (Courtesy of FAA) (item 16, .PDF, 846 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40392439&FileExtension=.PDF&FileName=Photo%205%3A%20Rotor%20head%20and%20pitch%20link%20damage.%20(Courtesy%20of%20FAA)-Master.PDF

From the NTSB's public API. Aircraft are matched to registry aircraft by N-number and event date, checked against the reported serial number, make and model; the registry's history has gaps, so older matches can be wrong. Compare the reported make and model.

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