# NTSB CHI05CA120: Brantly Helicopter B-2B, N2274U, Lakeview, MI, May 20, 2005 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: May 20, 2005, 15:00 local (20:00 UTC) - Place: Lakeview, MI - Coordinates: 43.45222, -85.264724 - Nearby events: https://openairdocs.org/map.md?lat=43.4522&lon=-85.2647&mi=10 - Phase of flight: [Uncontrolled descent](https://openairdocs.org/ntsb-phases/650) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report September 13, 2005 - Report: Approved by Office Director - NTSB case key (mKey): 61700 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI05CA120 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/61700/pdf - Page: https://openairdocs.org/ntsb/CHI05CA120 ## Probable cause The dual student failed to maintain adequate rotor rpm during the practice autorotation and the instructor's delay in attempting remedial action. A factor associated with the accident was the soft terrain that was encountered. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - In flight collision with terrain/water, descent - uncontrolled - autorotation - simulated - rotor rpm - inadequate, dual student (cause) - remedial action - delayed, pilot in command(cfi) (cause) - terrain condition - soft (contributing factor) - Roll over, other ## Analysis The helicopter rolled over during a practice autorotation. The purpose of the flight was for the dual student to practice autorotations in preparation for a rotorcraft rating. He stated the accident occurred during the third autorotation of the flight. The student reported that during the autorotation the airspeed decreased below 40 miles per hour and the rotor rpm decayed. He stated the CFI took control of the throttle, rolling it on and off about three times, but they were too slow and low. He stated the helicopter impacted the ground "hard." The student reported that he did not notice a mechanical failure/malfunction with the helicopter, reporting that they just got too slow and the rotor rpm decayed. He continued to report, "I learned later that when practicing autorotations, I should not roll the throttle to idle, because there is a governor that keeps it at about 2,000 rpm when the collective is lowered." He stated his CFI never said anything to him about not rolling the throttle to idle. The CFI stated the engine quit during the simulated engine failure. He stated they made a full touchdown autorotation into a soft field and the left skid dug into the terrain causing the helicopter roll over. ## Factual narrative On May 20, 2005, at 1500 eastern standard time, a Brantly B-2B, N2274U, collided with the terrain during a practice autorotation in Lakeview, Michigan. Neither the certified flight instructor (CFI) nor the private rated dual student were injured. The helicopter was substantially damaged. The 14 Code of Federal Regulation Part 91 instructional flight was operating in visual meteorological conditions without a flight plan. The flight originated in Lakeview, Michigan. The purpose of the flight was for the private pilot, who held single-engine land and single-engine sea ratings, to practice autorotations in preparation for a rotorcraft rating. He stated the accident occurred during the third autorotation of the flight. The student reported that during the autorotation the airspeed decreased below 40 miles per hour and the rotor rpm decayed. He stated the CFI took control of the throttle and rolled it on and off about three times, but they were too slow and low. He stated the helicopter impacted the ground "hard." The student reported that he did not notice a mechanical failure/malfunction with the helicopter, reporting that they just got too slow and the rotor rpm decayed. He continued to report, "I learned later that when practicing autorotations, I should not roll the throttle to idle, because there is a governor that keeps it at about 2,000 rpm when the collective is lowered." He stated his CFI never said anything to him about not rolling the throttle to idle. The CFI stated the engine quit during the simulated engine failure. He stated they made a full touchdown autorotation into a soft field and the left skid dug into the terrain causing the helicopter roll over. The last annual inspection on the helicopter was completed on May 10, 2005. During this inspection the idle rpm was found to be set at 1,080 rpm. The idle rpm was adjusted to 850 rpm. ## Aircraft - Registration: [N2274U](https://openairdocs.org/deregistered/N2274U-2012-08-13), registration cancelled 2012-08-13, S/N 439, built 1965 (OpenAirDocs) - Reported make and model: Brantly Helicopter B-2B - Registry model: [Brantly B-2B](https://openairdocs.org/model/brantly-b-2b) (registry code 1440506) (OpenAirDocs) - Registry engine: [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series) (registry code 41514, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 439 - Engines: Lycoming VIO-360 180 horsepower reciprocating - Damage: Substantial damage - Flight: Instructional, Part 91 - Operator: Doug Geesey - Registered owner: Dragonfly Aviation, Inc. - Airworthiness certificate: Standard, Normal - Departed: 13C, Lakeview, MI - Destination: 13C, Lakeview, MI ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 76; injuries: none; commercial, flight instructor; airplane ratings: multi-engine land, single-engine land, single-engine sea; instrument ratings: airplane; medical: class 2, with waivers/limitations; seat: left; flight hours: 35,000 total, 200 in this make and model - Student pilot; age 46; private; airplane ratings: single-engine sea, single-engine land; medical: class 2, without waivers/limitations ## Weather - Conditions: Visual (VMC), Day ## 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 20050520013569A](https://openairdocs.org/incident/20050520013569A), May 20, 2005: Hynes B2B, Lakeview, MI, Destroyed. (-23) On 5/20/05, the instructor is given lesson to an individual, who hold private pilot certificate but a student pilot for the helicopter training. While… ## Other investigations on N2274U (2) 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. - [NTSB WPR09LA039](https://openairdocs.org/ntsb/WPR09LA039), Nov 17, 2008: Brantly B-2B (N2274U), Camas, WA, substantial damage. Probable cause: A loss of engine power for undermined reasons. Contributing to the accident was the low altitude and airspeed, which precluded making a safe autorotation. - [NTSB FTW66A0042](https://openairdocs.org/ntsb/FTW66A0042), Nov 6, 1965: Brantly B-2B (N2274U), Wynne Wood, OK, substantial damage 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.