# NTSB CEN18CA294: Robinson R22, N410MM, Sterling City, TX, June 17, 2018 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: June 17, 2018 - Place: Sterling City, TX - Coordinates: 31.833055, -100.980834 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=31.8331&lon=-100.9808&mi=10 - Phase of flight: [Standing](https://openairdocs.org/ntsb-phases/150) (OpenAirDocs' grouping) - Defining event: [Standing-engine(s) operating: Miscellaneous/other](https://openairdocs.org/ntsb-events/900) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report March 18, 2019 - Report: Approved by Office Director - NTSB office: Central Region - NTSB case key (mKey): 97876 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN18CA294 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/97876/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=97876 - Page: https://openairdocs.org/ntsb/CEN18CA294 ## Probable cause The pilot’s improper decision to exit the helicopter without shutting down the engine, which allowed the collective/throttle to increase and resulted in a loss of control of the unattended helicopter. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: use of policy/procedure](https://openairdocs.org/ntsb-findings/02063032): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Robinson Helicopter R22 BETA, 2 cases](https://openairdocs.org/ntsb-findings/02063032/cases.md?model=7640110), [All aircraft, 191 cases](https://openairdocs.org/ntsb-findings/02063032/cases.md) - [Action: forgotten action/omission](https://openairdocs.org/ntsb-findings/02041035): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Robinson Helicopter R22 BETA, 3 cases](https://openairdocs.org/ntsb-findings/02041035/cases.md?model=7640110), [All aircraft, 440 cases](https://openairdocs.org/ntsb-findings/02041035/cases.md) - [Info processing/decision: decision making/judgment](https://openairdocs.org/ntsb-findings/02041520): Personnel issues › Action/decision · Pilot (probable cause); cases with it: [Robinson Helicopter R22 BETA, 17 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md?model=7640110), [All aircraft, 3,098 cases](https://openairdocs.org/ntsb-findings/02041520/cases.md) - [Performance/control parameters](https://openairdocs.org/ntsb-findings/01062000): Aircraft › Aircraft oper/perf/capability · Not attained/maintained (probable cause); cases with it: [Robinson Helicopter R22 BETA, 20 cases](https://openairdocs.org/ntsb-findings/01062000/cases.md?model=7640110), [All aircraft, 1,269 cases](https://openairdocs.org/ntsb-findings/01062000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Standing-engine(s) operating: Miscellaneous/other](https://openairdocs.org/ntsb-events/900) (defining event); cases with it: [Robinson Helicopter R22 BETA, 24 cases](https://openairdocs.org/ntsb-events/900/sequence.md?model=7640110), [All aircraft, 1,556 cases](https://openairdocs.org/ntsb-events/900/sequence.md) - [Standing-engine(s) operating: Loss of control on ground](https://openairdocs.org/ntsb-events/230); cases with it: [Robinson Helicopter R22 BETA, 13 cases](https://openairdocs.org/ntsb-events/230/sequence.md?model=7640110), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Standing-engine(s) operating: Part(s) separation from AC](https://openairdocs.org/ntsb-events/338); cases with it: [Robinson Helicopter R22 BETA, 9 cases](https://openairdocs.org/ntsb-events/338/sequence.md?model=7640110), [All aircraft, 563 cases](https://openairdocs.org/ntsb-events/338/sequence.md) ## Analysis The pilot exited the helicopter with the engine set to idle power. Subsequently, the collective/throttle increased due to the engine vibrations, and the helicopter became light on the skids. The helicopter rocked back on the tail, which separated the tail rotor from the helicopter and damaged the main rotor blades. The manufacturer had previously issued a safety notice, which stated to never exit the helicopter unattended with the engine running and the rotors turning because the collective can "creep up, increasing both pitch and throttle, allowing the helicopter to lift off or roll out of control," as occurred in this accident. ## Factual narrative The pilot reported to the Federal Aviation Administration Inspector that he was working with the land owner to conduct cattle herding with the helicopter. He landed in the field and got out to speak with the land owner about the flight. The pilot left the helicopter at idle power when he exited. While speaking to the land owner, the collective/throttle increased and the helicopter rocked back on the tail, separating the tail rotor. The main rotor blades were then damaged when the helicopter settled back down.The helicopter received substantial damage to the tail rotor and main rotor blades. Robinson Helicopter's issued Safety Notice SN-17 in November 1984, revised June 1994, which stated: NEVER EXIT HELECOPTER WITH ENGINE RUNNING Several accidents have occurred when pilots momentarily left their helicopters unattended with the engine running and rotors turning. The collective can creep up, increasing both pitch and throttle, allowing the helicopter to lift off or roll out of control. ## Aircraft - Registration: [N410MM](https://openairdocs.org/deregistered/N410MM-2018-10-17), registration cancelled 2018-10-17, S/N 3599, built 2004 (OpenAirDocs) - Reported make and model: Robinson R22 (BETA) - Registry model: [Robinson Helicopter R22 BETA](https://openairdocs.org/model/robinson-helicopter-r22-beta) (registry code 7640110) (OpenAirDocs) - Registry engine: [Lycoming O-360 series](https://openairdocs.org/engine/lycoming-o-360-series) (registry code 41575, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 3599 - Year built: 2004 - Engines: Lycoming O-360 SERIES reciprocating - Damage: Substantial damage - Flight: Business, Part 91 - Operator: Concho Aviation Llc - Registered owner: Concho Aviation Llc - Airworthiness certificate: Standard, Normal - Departed: Sterling City, TX - Destination: Sterling City, TX ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 39; injuries: none; commercial; medical: class 2, without waivers/limitations; seat: none ## Weather - Conditions: Visual (VMC), Day - Observed at: GOF, 39 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 20180617015569A](https://openairdocs.org/incident/20180617015569A), Jun 17, 2018: Robinson Helicopter R22 BETA, Sterling City, TX, Destroyed. On June 4, 2018, at approximately 1000 CDT, N410MM, an R-22BETA helicopter was left idling in a field near Sterling City, Texas. The pilot exited the running… ## Docket (2 files) The files NTSB released with the investigation on September 27, 2018, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=97876. 125 KB in all. - Record of Conversation (item 1, .PDF, 79 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466963&FileExtension=.PDF&FileName=Record%20of%20Conversation-Master.PDF - Robinson Helicopter Safety Notice (item 2, .PDF, 45 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40466964&FileExtension=.PDF&FileName=Robinson%20Helicopter%20Safety%20Notice-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.