# NTSB GAA16LA325: MD Helicopter 369E, N155NR, Brainerd, MN, June 17, 2016 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 17, 2016, 14:00 local (19:00 UTC) - Place: Brainerd, MN - Coordinates: 46.314445, -94.537223 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=46.3144&lon=-94.5372&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Defining event: [Enroute-cruise: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report September 6, 2017 - Report: Approved by Office Director - NTSB office: General Aviation Accidents - Parties: FAA - NTSB case key (mKey): 93440 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=GAA16LA325 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/93440/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=93440 - Page: https://openairdocs.org/ntsb/GAA16LA325 ## Probable cause The failure of the helicopter’s windscreen for reasons that could not be determined based on the available information, which resulted in substantial damage to the main rotor blades and horizontal stabilizer. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Windows-windshield system: flight compartment windows](https://openairdocs.org/ntsb-findings/01035610): Aircraft › Aircraft structures · Failure (probable cause); cases with it: [MD Helicopters 369E, 1 case](https://openairdocs.org/ntsb-findings/01035610/cases.md?model=3030008), [All aircraft, 42 cases](https://openairdocs.org/ntsb-findings/01035610/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Enroute-cruise: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) (defining event); cases with it: [MD Helicopters 369E, 1 case](https://openairdocs.org/ntsb-events/338/sequence.md?model=3030008), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) - [Enroute-cruise: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [MD Helicopters 369E, 2 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=3030008), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) ## Analysis The commercial pilot reported that, during an aerial observation flight near known thunderstorms, the right center windscreen shattered. The pilot sustained multiple facial lacerations, but he was able to land the helicopter near a highway without further incident. The pilot reported that he did not see anything strike the windscreen and found no evidence of a bird strike. Examination of the helicopter revealed that debris from the windscreen substantially damaged two of the main rotor blades and the leading edge of the horizontal stabilizer. Examination of the windscreen and its frame revealed evidence of cracking that originated in the center of the windscreen and propagated outward, consistent with impact forces from outside the helicopter. DNA from samples taken from portions of the windscreen matched DNA from a Western Kingbird; however, given the extent of the damage to the windscreen, the small size of the Western Kingbird, and the pilot's statement, it is likely that this DNA was due to a previous bird strike and did not result in the failure of the windscreen. Therefore, the reason for the windscreen failure could not be determined. ## Factual narrative On June 17, 2016 about 1400 central daylight time (CDT), an MD Helicopters Inc., 369E, N155NR, sustained a windscreen failure in flight, 20 miles south of Brainerd Lakes Regional Airport, Minnesota. The helicopter was registered to the State of Minnesota Department of Natural Resources Enforcement Division and operated as a visual flight rules (VFR) public use local flight under the provisions of 14 Code of Federal Regulations Part 91. Visual meteorological conditions prevailed for the flight, and company VFR flight following was in effect. The commercial pilot reported that he conducted the aerial observation flight near known thunderstorms and that both the passenger and pilot doors had been removed from the helicopter. He reported that, about 20 miles south of his destination, he decreased the helicopter's airspeed to about 110 mph because, "it began to feel a little bumpy." The pilot added that, "suddenly with no warning," the right center windscreen shattered. The helicopter's nose dropped immediately, and the pilot lowered the collective. After slowing the helicopter to maintain control, the pilot conducted a precautionary landing without further incident. The pilot reported that he did not see anything strike the windscreen and found no evidence of a bird strike. Two of the helicopter's main rotor blades and the horizontal stabilizer sustained substantial damage. The pilot sustained facial lacerations, and the observer on board did not sustain any injury. DNA samples taken from portions of the windscreen were sent to the Smithsonian Feather Identification Laboratory in Washington, DC. Microscopic examination of one of the samples revealed evidence of feathers. The DNA from the feathers matched the Western Kingbird (Tyrannus verticalis), which is a very small bird. According to the Federal Aviation Administration Inspector who responded to the accident, the right front windscreen failed in cruise flight for unknown reasons. A post-accident examination of the helicopter by the inspector revealed that debris from the windscreen had made gouges in the main rotor blades and the horizontal stabilizer. A significant portion of the windscreen was not recovered. Examination of the recovered windscreen pieces revealed evidence of cracking that originated on the external surface of the center of the windscreen and then propagated outward. ## Aircraft - Registration: [N155NR](https://openairdocs.org/aircraft/N155NR), registered now, S/N 0623E, built 2015 (OpenAirDocs) - Reported make and model: MD HELICOPTER 369E (500) - Registry model: [MD Helicopters 369E](https://openairdocs.org/model/md-helicopters-369e) (registry code 3030008) (OpenAirDocs) - Registry engine: [Rolls-Royce 250-C20R/2](https://openairdocs.org/engine/rolls-royce-250-c20r-2) (registry code 54185, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 0623E - Year built: 2015 - Airframe hours: 91.1 - Engines: Rolls Royce C20B 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Public aircraft - state, Public use - Operator: Minnesota Department of Natural Resources - Registered owner: Minnesota Department of Natural Resources - Airworthiness certificate: Standard, Normal - Departed: STC, ST CLOUD, MN - Destination: BRD, BRAINERD, MN - Flight plan: Company VFR - Equipment: Electronic multifunction display, Onboard weather, Electronic primary flight display, Handheld GPS ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 63; injuries: minor; commercial, flight instructor; airplane ratings: single-engine land; instrument ratings: helicopter; medical: class 2, with waivers/limitations; last flight review September 1, 2015; seat: right; restraint: 4-point; flight hours: 7,958 total, 85 in this make and model, 7,455 as pilot in command, 88 in the last 90 days, 61 in the last 30 days, 1 in the last 24 hours - Other flight crew; age 49; injuries: minor; seat: left; restraint: 4-point; flight hours: 0 total, 0 in this make and model ## Weather - Conditions: Visual (VMC), Day - Wind: 360° at 9 knots, gusting 19 - Visibility: 10 statute miles - Lowest ceiling: 3,000 ft broken - Temperature: 72 °F, dew point 63 °F - Altimeter: 30.15 inHg - Observed at: KBRD, 18 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 20160617022419A](https://openairdocs.org/incident/20160617022419A), Jun 17, 2016: Md MD-369E, Brainerd, MN, Substantial damage. Pilot windscreen shattered while in cruise about 2O miles south of brd at 2200' MSL and an airspeed of approximately 110 mph. Pilot was able to land aircraft… ## Docket (5 files) The files NTSB released with the investigation on August 7, 2017, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=93440. 5.5 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 4.0 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40454912&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - MD Helicopter Report (item 2, .PDF, 485 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40454913&FileExtension=.PDF&FileName=MD%20Helicopter%20Report-Master.PDF - Smithsonian Institute Findings (item 3, .PDF, 94 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40454914&FileExtension=.PDF&FileName=Smithsonian%20Institute%20Findings-Master.PDF - Material Laboratory (item 4, .PDF, 5 photos, 345 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40454915&FileExtension=.PDF&FileName=Material%20Laboratory-Master.PDF - Photos (Courtesy of FAA) (item 5, .PDF, 4 photos, 542 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40454917&FileExtension=.PDF&FileName=Photos%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. --- 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.