# NTSB CEN11CA638: Enstrom F-28F, N228F, Menominee, MI, August 29, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: August 29, 2011, 13:15 local (18:15 UTC) - Place: Menominee, MI - Coordinates: 45.126667, -87.638336 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=45.1267&lon=-87.6383&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-hover: Loss of control in flight](https://openairdocs.org/ntsb-events/240) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report November 3, 2011 - Report: Approved by Office Director - NTSB office: Central Region - Parties: Federal Aviation Administration - NTSB case key (mKey): 81763 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN11CA638 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/81763/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=81763 - Page: https://openairdocs.org/ntsb/CEN11CA638 ## Probable cause The pilot's failure to maintain control of the helicopter during a hover. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Performance/control parameters](https://openairdocs.org/ntsb-findings/01062000): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Enstrom F-28F, 1 case](https://openairdocs.org/ntsb-findings/01062000/cases.md?model=3300412), [All aircraft, 1,269 cases](https://openairdocs.org/ntsb-findings/01062000/cases.md) - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Enstrom F-28F, 2 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=3300412), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-hover: Loss of control in flight](https://openairdocs.org/ntsb-events/240) (defining event); cases with it: [Enstrom F-28F, 3 cases](https://openairdocs.org/ntsb-events/240/sequence.md?model=3300412), [All aircraft, 5,002 cases](https://openairdocs.org/ntsb-events/240/sequence.md) - [Maneuvering-hover: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Enstrom F-28F, 5 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=3300412), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis According to the pilot, the purpose of the company test flight was to measure collective stick forces with the collective bias disabled. The pilot, who was the helicopter's only occupant, lifted the helicopter into a hover and then hovered clear of any obstacles. He reported that the collective controls were heavy, as expected, but the helicopter was very controllable. During his attempt to position a force gauge between his hand and the collective grip, the pilot lost control of the helicopter and it landed hard onto the ramp. The helicopter's tail rotor blades impacted the ramp and the helicopter came to rest upright. A postaccident examination of the helicopter showed that the tail rotor blades were bent and the tail rotor driveshaft was sheared. The pilot reported that he should have taken an observer or other personnel on the flight to assist while he concentrated on flying the helicopter. ## Factual narrative According to the pilot, the purpose of the company test flight was to measure collective stick forces with the collective bias disabled. The pilot, who was the helicopter's only occupant, lifted the helicopter into a hover and then hovered clear of any obstacles. He reported the collective controls were heavy as expected, but the helicopter was very controllable. During his attempt to position a force gauge between his hand and the collective grip, the pilot lost control of the helicopter and it landed hard onto the ramp. The helicopter's tail rotor blades impacted the ramp and the helicopter came to rest upright. A postaccident examination of the helicopter showed the tail rotor blades were bent, and the tail rotor drive shaft was sheared. The pilot reported he should have taken an observer or other personnel on the flight to assist while he concentrated on flying the helicopter. ## Aircraft - Registration: [N228F](https://openairdocs.org/aircraft/N228F), registered now, S/N 819, built 2007 (OpenAirDocs) - Reported make and model: ENSTROM F-28F - Registry model: [Enstrom F-28F](https://openairdocs.org/model/enstrom-f-28f) (registry code 3300412) (OpenAirDocs) - Registry engine: [Lycoming HIO-360-F1AD](https://openairdocs.org/engine/lycoming-hio-360-f1ad) (registry code 41896, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 819 - Airframe hours: 232 - Engines: LYCOMING HIO-360-F1AD 225 horsepower reciprocating - Damage: Substantial damage - Flight: Flight test, Part 91 - Operator: Enstrom Helicopter Corp - Registered owner: Enstrom Helicopter Corp - Airworthiness certificate: Standard, Normal - Last inspection: Annual, September 29, 2010 - Departed: MNM, Menominee, MI - Destination: MNM, Menominee, MI - Airport: MNM, Menominee-Marinette Twin City ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 53; injuries: none; private, commercial; airplane ratings: single-engine land; instrument ratings: airplane; medical: class 2, with waivers/limitations; last flight review May 5, 2011; seat: right; flight hours: 2,200 total, 152 in this make and model, 1,970 as pilot in command, 31 in the last 90 days, 8 in the last 30 days ## Weather - Conditions: Visual (VMC), Day - Wind: 230° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none - Temperature: 75 °F - Altimeter: 29.89 inHg ## 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 20110829020209A](https://openairdocs.org/incident/20110829020209A), Aug 29, 2011: Enstrom F-28F, Menominee, MI, Substantial damage. According to the pilot, the purpose of the company test flight was to measure collective stick forces with the collective bias disabled. The pilot, who was the… ## Docket (1 files) The files NTSB released with the investigation on September 16, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=81763. 793 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 793 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40354032&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-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.