# NTSB CEN09CA218: Bell 222, N222LL, Milliken, CO, March 13, 2009 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: March 13, 2009, 14:25 local (19:25 UTC) - Place: Milliken, CO - Coordinates: 40.325279, -104.855552 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=40.3253&lon=-104.8556&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 June 11, 2009 - Report: Approved by Office Director - NTSB office: Central Region - Parties: FAA Denver FSDO - NTSB case key (mKey): 73510 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN09CA218 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/73510/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=73510 - Page: https://openairdocs.org/ntsb/CEN09CA218 ## Probable cause The separation of the left engine cowling for undetermined reasons. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Power plant: engine cowling system](https://openairdocs.org/ntsb-findings/01057110): Aircraft › Aircraft power plant · Not specified (probable cause); cases with it: [Bell 222, 1 case](https://openairdocs.org/ntsb-findings/01057110/cases.md?model=1182122), [All aircraft, 11 cases](https://openairdocs.org/ntsb-findings/01057110/cases.md) - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Bell 222, 2 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=1182122), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Prior to flight: Aircraft inspection event](https://openairdocs.org/ntsb-events/050); cases with it: [Bell 222, 1 case](https://openairdocs.org/ntsb-events/050/sequence.md?model=1182122), [All aircraft, 229 cases](https://openairdocs.org/ntsb-events/050/sequence.md) - [Enroute-cruise: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338) (defining event); cases with it: [Bell 222, 1 case](https://openairdocs.org/ntsb-events/338/sequence.md?model=1182122), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) ## Analysis A witness on the ground was watching the helicopter when he saw several pieces fall off and subsequently land in his and a neighbor's yard. The commercial pilot said that he was en route cruising at approximately 1,500 feet above ground level when he felt a "bump on the controls" and heard a "bang" and thought that he had hit a bird. He returned to his departure airport 45 miles away for an otherwise uneventful landing. On postflight inspection, the pilot discovered that the lower portion of the left engine cowling was missing and that the cowling pieces had struck both main rotor blades and both tail rotor blades, but no evidence of bird remains were found. The impact caused substantial damage to the left engine cowling, both tail rotor blades, the tail rotor yoke, and the tail rotor gearbox. The pilot and his passenger were not injured. The pilot said that before departure he had conducted a preflight inspection; however, the Federal Aviation Administration inspector who examined the helicopter and the separated pieces of the left engine cowling found no evidence of bird remains and no damage to the cowling latches that would have prevented them from operating normally prior to the accident. ## Factual narrative A witness on the ground was actively watching the helicopter when he saw several pieces fall off the helicopter and subsequently land in his yard and a neighbor's yard. The commercial pilot said he was in enroute cruise at approximately 1,500 feet above ground level when he felt a "bump on the controls" and heard a "bang" and thought he had had hit a bird. He returned to his departure airport 45 miles away for an otherwise uneventful landing. On post flight inspection the pilot discovered the lower portion of the left engine cowling was missing and there was evidence the cowling pieces had struck both main rotor blades and both tail rotor blades, but no evidence of bird remains were found. The impact caused substantial damage to the left engine cowling, both tail rotor blades, the tail rotor yoke, and the tail rotor gearbox. The pilot and his passenger were not injured. The pilot said that before departure he had conducted a preflight inspection, however the FAA Inspector that examined the helicopter, and the separated pieces of the left engine cowling, found no evidence of bird remains and no damage to the cowling latches that would have prevented them from operating normally prior to the accident. ## Aircraft - Registration: [N222LL](https://openairdocs.org/aircraft/N222LL), registered now, S/N 47060, built 1981 (OpenAirDocs) - Reported make and model: BELL 222 - Registry model: [Bell 222](https://openairdocs.org/model/bell-222) (registry code 1182122) (OpenAirDocs) - Registry engine: [Lycoming LTS-101 series](https://openairdocs.org/engine/lycoming-lts-101-series) (registry code 41560, turbo-shaft) (OpenAirDocs) - Category: Helicopter - Serial number: 47060 - Airframe hours: 9895 - Engines: Lycoming LTS-101 SER 620 horsepower turbo shaft; Lycoming LTS-101 SER 620 horsepower turbo shaft - Damage: Substantial damage - Flight: Executive/Corporate, Part 91 - Airworthiness certificate: Standard, Normal - Last inspection: Annual, July 16, 2008, 29 hours before - Departed: KAPA, Denver, CO - Destination: Weld County, CO - Airport: FNL, Ft Collins-Loveland Municipal ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 53; injuries: none; commercial; airplane ratings: multi-engine land, single-engine land; instrument ratings: helicopter, airplane; medical: class 3, with waivers/limitations; last flight review December 5, 2008; seat: right; flight hours: 6,780 total, 170 in this make and model, 50 in the last 90 days, 15 in the last 30 days, 0 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 160° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 48 °F, dew point 7 °F - Altimeter: 30.00 inHg - Observed at: KFLN, 10 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 20090313002369A](https://openairdocs.org/incident/20090313002369A), Mar 13, 2009: Bell 222, Milliken, CO, Substantial damage. (-23) Aircraft departed apa, 30 minutes into flight while over the town of Milliken, CO the left engine cowling opened striking both main rotor blades causing… ## Docket (3 files) The files NTSB released with the investigation on May 4, 2009, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=73510. 1.9 MB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 1.5 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40311727&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Passenger Statement (item 2, .PDF, 193 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40311728&FileExtension=.PDF&FileName=Passenger%20Statement-Redacted.PDF - Witness Statement (item 3, .PDF, 227 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40377169&FileExtension=.PDF&FileName=Witness%20Statement-Redacted.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.