# NTSB SEA05LA120: MBB BO-105, N314MS, Billings, MT, June 17, 2005 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: June 17, 2005, 15:30 local (22:30 UTC) - Place: Billings, MT - Coordinates: 45.807777, -108.542778 - Nearby events: https://openairdocs.org/map.md?lat=45.8078&lon=-108.5428&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report October 27, 2005 - Report: Approved by Office Director - Parties: Helena FSDO - NTSB case key (mKey): 61773 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=SEA05LA120 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/61773/pdf - Page: https://openairdocs.org/ntsb/SEA05LA120 ## Probable cause The pilot's improper in-flight decision to continue a simulated engine-out autorotation after sensing an excessive descent rate at 100 feet above the ground. Factors include the excessive descent rate, variable winds, and a high density altitude. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Hard landing, landing - flare/touchdown - emergency procedure - simulated, pilot in command - autorotation - initiated, pilot in command - in-flight planning/decision - improper, pilot in command (cause) - weather condition - variable wind (contributing factor) - descent - excessive, pilot in command (contributing factor) - weather condition - high density altitude (contributing factor) - go-around - not performed, pilot in command (cause) ## Analysis The instructor pilot had just finished giving the other pilot a proficiency check, and had then taken control of the aircraft so that he could perform some maneuvers for his own proficiency. He performed one simulated engine-out autorotation to a touchdown, and was completing his second, when the accident occurred. He initiated the autorotation from about 1,000 feet above the ground (agl), and began establishing a flare attitude at an altitude of 100 feet agl. At that time he noticed that the descent rate of the helicopter was excessive, but instead of adding power along with the increase in collective, he decided to continue the simulation of the power loss. Just prior to touchdown, the pilot established a landing attitude and used all of the available collective to cushion the landing. When the helicopter touched down, the descent rate was still greater than the pilot desired, and immediately after contacting the ground, the main rotor flexed downward and contacted the top of the tail boom. The pilot reported that there were no problems with the aircraft's flight controls or engine, but the variable wind had changed directions during the descent from 1,000 feet agl, and the aircraft was therefore landing with a tailwind. In addition, the pilot states that the density altitude was approximately 5,700 feet, which left little room for error. In his discussion with the NTSB, the pilot stated that under the conditions, he should have initiated a go-around when he sensed the excessive descent rate at 100 feet agl. ## Factual narrative On June 17, 2005, approximately 1530 Pacific daylight time, an MBB BO-105 helicopter, N314MS, landed hard during a simulated autorotation in an area north of Logan International Airport, Billings, Montana. The certified flight instructor, who was flying at the time, as well as his pilot-rated passenger, were not injured, but the aircraft, which is owned and operated by Metro Aviation, Inc., sustained substantial damage. The 14 CFR part 91 proficiency flight, which departed Logan International about 60 minutes prior to the accident, was being operated in visual meteorological conditions. No flight plan had been filed. According to the instructor pilot, he had just finished giving the other pilot a proficiency check, and had then taken control of the aircraft so that he could perform some maneuvers for his own proficiency. He performed one simulated engine-out autorotation to a touchdown, and was completing his second when the accident occurred. He said that he initiated the autorotation from about 1,000 feet above the ground (agl), and began establishing a flare attitude at an altitude of 100 feet agl. At that time he noticed that the descent rate of the helicopter was excessive, but instead of adding power along with the increase in collective, he decided to continue the simulation of the power loss. Just prior to touchdown, the pilot established a landing attitude and used all of the available collective to cushion the landing. When the helicopter touched down, the descent rate was still greater than the pilot desired, and immediately after contacting the ground, the main rotor flexed downward and contacted the top of the tail boom. According to the pilot, there were no problems with the aircraft's flight controls or engine. He further stated that he felt that the variable wind had changed directions during his descent from 1,000 feet agl, and that he was therefore inadvertently landing downwind. In addition, he felt that the high density altitude (approximately 5,700 feet) left little room for error. In his discussion with the NTSB, the pilot stated that under the conditions, he should have initiated a go-around when he sensed the excessive descent rate at 100 feet agl. ## Aircraft - Registration: N314MS (not matched to a registry record) - Reported make and model: MBB BO-105 - Category: Helicopter - Serial number: S772 - Engines: Allison 250-C-20B 420 horsepower turbo shaft - Damage: Substantial damage - Flight: Other work use, Part 91 - Registered owner: Metro Aviation, Inc. - Airworthiness certificate: Standard, Normal - Departed: KBIL, Billings, MT - Destination: KBIL ## Flight crew As NTSB recorded them. NTSB leaves out names. - Flight instructor; age 34; injuries: none; commercial, flight instructor; instrument ratings: helicopter; medical: class 2, without waivers/limitations; last flight review April 1, 2005; seat: left; flight hours: 2,730 total, 177 in this make and model, 2,361 as pilot in command, 43 in the last 90 days, 24 in the last 30 days, 2 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Visibility: 10 statute miles - Temperature: 73 °F ## 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 20050617011769A](https://openairdocs.org/incident/20050617011769A), Jun 17, 2005: Bolkms BO105S, Billings, MT, Substantial damage. (-23) During a proficiency flight check, the instructor pilot took the controls of the helicopter. At approximately 100 feet above ground level, the pilot… 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.