# NTSB ERA10LA379: Garlick Helicopters OH-58A+, N48LA, Newport, TN, July 28, 2010 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Limited investigation · Final report - Date: July 28, 2010, 09:00 local (13:00 UTC) - Place: Newport, TN - Coordinates: 35.970001, -83.190002 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=35.9700&lon=-83.1900&mi=10 - Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping) - Defining event: [Standing-engine(s) operating: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed, report June 20, 2011 - Report: Approved by Office Director - NTSB office: Eastern Region Aviation - Parties: FAA/FSDO, Bell Helicopter - NTSB case key (mKey): 76780 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=ERA10LA379 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/76780/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=76780 - Page: https://openairdocs.org/ntsb/ERA10LA379 ## Probable cause Inadequate maintenance inspections of the main rotor blade inertia screw holes, which resulted in a main rotor blade failure due to fatigue. Contributing to the accident was the pilot's inadequate preflight inspection of the main rotor blades. ## 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 · Fatigue/wear/corrosion (probable cause); cases with it: [Garlick Helicopters OH-58A+, 1 case](https://openairdocs.org/ntsb-findings/01046210/cases.md?model=3740006), [All aircraft, 60 cases](https://openairdocs.org/ntsb-findings/01046210/cases.md) - [Inspection: scheduled/routine inspection](https://openairdocs.org/ntsb-findings/02061520): Personnel issues › Task performance · Maintenance personnel (probable cause); cases with it: [Garlick Helicopters OH-58A+, 1 case](https://openairdocs.org/ntsb-findings/02061520/cases.md?model=3740006), [All aircraft, 167 cases](https://openairdocs.org/ntsb-findings/02061520/cases.md) - [Inspection: preflight inspection](https://openairdocs.org/ntsb-findings/02061510): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Garlick Helicopters OH-58A+, 1 case](https://openairdocs.org/ntsb-findings/02061510/cases.md?model=3740006), [All aircraft, 551 cases](https://openairdocs.org/ntsb-findings/02061510/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Standing-engine(s) operating: Sys/Comp malf/fail (non-power)](https://openairdocs.org/ntsb-events/330) (defining event); cases with it: [Garlick Helicopters OH-58A+, 1 case](https://openairdocs.org/ntsb-events/330/sequence.md?model=3740006), [All aircraft, 994 cases](https://openairdocs.org/ntsb-events/330/sequence.md) ## Analysis The pilot completed a preflight inspection and found no problems with the helicopter. He then completed a normal start procedure and increased the rpm to 100 percent flight idle. He was about to increase the collective, when he felt a violent shake, heard a loud noise, and the helicopter began to come apart. A postaccident examination of the wreckage revealed that an outboard 2-foot section of main rotor blade had separated. Metallurgical examination of the separated blade revealed that a fatigue crack originated from an inertia screw hole, located at the bottom surface of the spar portion of the main rotor blade. That crack propagated more than 50 percent of the spar cross section, before fracturing consistent with overstress. A manufacturer alert bulletin instructed operators to visually inspect the inertia screw hole locations on the blade spar with a 10X magnifying glass for cracks and corrosion every 8 hours of flight, or 32 cumulative flights. The outboard section of main rotor blade was secured with eight inertia screws. Although the inertia screw holes were supposed to receive a maintenance inspection every 8 flight hours, they were also a preflight inspection item for the pilot. Review of the helicopter's maintenance logbooks revealed an entry stating that the inertia screw holes had been inspected within the past 8 flight hours; however, corrosion was present in the inertia screw hole that failed. The corrosion and fatigue was most likely present for more than 8 flight hours. ## Factual narrative On July 28, 2010, about 0900 eastern daylight time, an experimental Garlick Helicopters OH-58A+, N48LA, operated by B & S Air Inc., was substantially damaged while standing in a field, with the engine operating, near Newport, Tennessee. The certificated commercial pilot incurred minor injuries. The aerial application flight was conducted under the provisions of 14 Code of Federal Regulations Part 137. Visual meteorological conditions prevailed and no flight plan was filed for the planned flight to Jackson, Tennessee. According to the pilot's written statement, he performed a normal preflight inspection and found no problems with the helicopter. He then completed a normal start procedure and increased rpm to 100 percent flight idle. The pilot was about to increase collective, when he felt a violent shake, heard a loud noise, and the helicopter began to come apart. He then saw the transmission and rotor blades on the ground in front of helicopter. He subsequently shut off the engine and exited the helicopter. Examination of the wreckage by a Federal Aviation Administration (FAA) inspector revealed that an outboard 2-foot section of main rotor blade had separated. The transmission had also separated, which resulted in substantial damage to the fuselage. The separated section of main rotor blade was forwarded to the NTSB Materials Laboratory, Washington, DC, for further examination. Metallurgical examination revealed that a fatigue crack originated from an inertia screw hole, located at the bottom surface of the spar portion of the main rotor blade. That crack propagated more than 50 percent of the spar cross section, before fracturing consistent with overstress. The helicopter was manufactured in 1970 and delivered to the U.S. Army. In 1995, it was transferred from the U.S. Army to state law enforcement. The helicopter was subsequently equipped for agricultural application and issued an FAA experimental airworthiness certificate in 2005. According to maintenance records and the pilot, the helicopter's most recent 100-hour inspection was completed on June 15, 2010. At that time, the helicopter had accumulated approximately 6,704 total hours of operation. The helicopter had accumulated about 76 additional hours of operation, from the time of the last 100-hour inspection, until the accident. According to a representative from the helicopter manufacturer, Bell Military Alert Bulletin USA-OH-58-87-1 was issued on June 12, 1987, requesting military operators to visually inspect the inertia screw hole locations on the blade spar with a 10X magnifying glass for cracks and corrosion. The inspection should be done at every 8 hours of flight, or 32 cumulative flights. Subsequently, on April 12, 2007, Bell Operations Safety Notice OSN-GEN-07-38 was issued to all OH-58 operators and referenced the Bell Military Alert Bulletin. According to the FAA inspector, the outboard section of main rotor blade was secured with eight inertia screws. Although the inertiascrew holes were supposed to receive a maintenance inspection every 8 flight hours, they were also a preflight inspection item for the pilot. Review of the helicopter's maintenance logbooks revealed an entry stating that the inertia screw holes had been inspected within the past 8 flight hours with no anomalies noted; however, the inspector observed corrosion present in the inertia screw hole that failed. ## Aircraft - Registration: [N48LA](https://openairdocs.org/aircraft/N48LA), registered now, S/N 70-15130, built 1970 (OpenAirDocs) - Reported make and model: GARLICK HELICOPTERS INC OH-58A+ - Registry model: [Garlick Helicopters OH-58A+](https://openairdocs.org/model/garlick-helicopters-oh-58a-plus) (registry code 3740006) (OpenAirDocs) - Registry engine: [Amateur-built UNKNOWN ENG](https://openairdocs.org/engine/amateur-built-unknown-eng) (registry code 99999) (OpenAirDocs) - Category: Helicopter - Serial number: 70-15130 - Engines: Allison C250-C20C 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: B & S Air Inc - Registered owner: B & S Air Inc - Airworthiness certificate: Special, Experimental (Special) - Last inspection: 100 hour, June 15, 2010, 76 hours before - Departed: NONE, Newport, TN - Destination: NONE, Jackson, TN - Airport: NONE, None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 22; injuries: none; commercial; instrument ratings: helicopter; medical: class 2, without waivers/limitations; last flight review February 8, 2010; seat: right; flight hours: 400 total, 210 in this make and model, 380 as pilot in command, 4 in the last 90 days, 4 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 79 °F, dew point 73 °F - Altimeter: 30.12 inHg - Observed at: TYS, 30 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 20100728039219A](https://openairdocs.org/incident/20100728039219A), Jul 28, 2010: Garlick Hel OH-58A+, Newport, TN, Destroyed. The pilot was increasing rotor blade pitch while in the take-off phase of flight. While still on the ground, helicopter experienced a rotor blade failure.… ## Docket (9 files) The files NTSB released with the investigation on May 5, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=76780. 3.4 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 837 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40343956&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Interview Summary (item 2, .PDF, 83 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40343957&FileExtension=.PDF&FileName=Interview%20Summary-Master.PDF - Materials Laboratory Factual Report (item 3, .PDF, 43 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40343958&FileExtension=.PDF&FileName=Materials%20Laboratory%20Factual%20Report-Master.PDF - Materials Laborator Factual Report Addendum (item 4, .PDF, 150 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40343959&FileExtension=.PDF&FileName=Materials%20Laborator%20Factual%20Report%20Addendum-Master.PDF - Excerpt From Maintenance Records (item 5, .PDF, 70 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40344677&FileExtension=.PDF&FileName=Excerpt%20From%20Maintenance%20Records-Redacted.PDF - Bell Military Alert Bulletin USA-OH-58-87-1 (item 6, .PDF, 36 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40343960&FileExtension=.PDF&FileName=Bell%20Military%20Alert%20Bulletin%20USA-OH-58-87-1-Master.PDF - Statement of Party Representatives to NTSB Investigation (item 7, .PDF, 1.3 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40344676&FileExtension=.PDF&FileName=Statement%20of%20Party%20Representatives%20to%20NTSB%20Investigation-Redacted.PDF - Evidence Control Form (item 8, .PDF, 93 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40343962&FileExtension=.PDF&FileName=Evidence%20Control%20Form-Master.PDF - Photo 1: Main Wreckage (Photo Courtesy of FAA) (item 9, .PDF, 722 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40343963&FileExtension=.PDF&FileName=Photo%201%3A%20%20Main%20Wreckage%20(Photo%20Courtesy%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. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.