# NTSB CEN11CA403: Bell 47G-4A, N24HM, Montgomery City, MO, June 18, 2011 - Type: NTSB accident investigation - Classification: Accident · No injuries · Data collection · Final report - Date: June 18, 2011, 18:45 local (23:45 UTC) - Place: Montgomery City, MO - Coordinates: 39.012779, -91.419441 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=39.0128&lon=-91.4194&mi=10 - Phase of flight: [Landing](https://openairdocs.org/ntsb-phases/550) (OpenAirDocs' grouping) - Defining event: [Landing: Hard landing](https://openairdocs.org/ntsb-events/092) - Highest injury: No injuries - Injuries: 1 uninjured - Status: Completed, report October 4, 2011 - Report: Approved by Office Director - NTSB office: Central Region - NTSB case key (mKey): 80823 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN11CA403 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/80823/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=80823 - Page: https://openairdocs.org/ntsb/CEN11CA403 ## Probable cause A loss of control during the precautionary landing, which resulted in inadvertent contact between the main rotor and the tailboom. Contributing to the accident was the overloaded condition. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Use of equip/info: aircraft control](https://openairdocs.org/ntsb-findings/02063040): Personnel issues › Task performance · Pilot (probable cause); cases with it: [Bell 47G-4A, 2 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md?model=1181031), [All aircraft, 9,295 cases](https://openairdocs.org/ntsb-findings/02063040/cases.md) - [Aircraft capability: maximum weight](https://openairdocs.org/ntsb-findings/01061035): Aircraft › Aircraft oper/perf/capability · Capability exceeded; cases with it: [Bell 47G-4A, 1 case](https://openairdocs.org/ntsb-findings/01061035/cases.md?model=1181031), [All aircraft, 152 cases](https://openairdocs.org/ntsb-findings/01061035/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Landing: Hard landing](https://openairdocs.org/ntsb-events/092) (defining event); cases with it: [Bell 47G-4A, 4 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=1181031), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) - [Landing: Loss of control on ground](https://openairdocs.org/ntsb-events/230); cases with it: [Bell 47G-4A, 1 case](https://openairdocs.org/ntsb-events/230/sequence.md?model=1181031), [All aircraft, 4,585 cases](https://openairdocs.org/ntsb-events/230/sequence.md) - [Landing: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Bell 47G-4A, 2 cases](https://openairdocs.org/ntsb-events/060/sequence.md?model=1181031), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) ## Analysis The pilot reported that he had returned from an agricultural application to reload the cleaning solution. Unbeknownst to the pilot, the helicopter was loaded with approximately 90 gallons of solution, instead of the expected 70 gallons for the flight. The pilot reported that he increased engine power and lifted off; however, immediately after lift off the engine and rotor speed began to decrease. He selected a suitable landing point and flared for touchdown about 10 feet above ground level to minimize the forward speed. The helicopter touched down on the rear portion of the landing skids and began to pitch forward. He applied aft cyclic control to prevent the helicopter from nosing over. He subsequently heard a bang and observed debris coming from the aircraft. He shut down the engine and secured the helicopter. A postaccident examination revealed that the main rotor had struck the tailboom resulting in substantial damage to the airframe. The pilot said the helicopter may have been on a slight incline when the solution was loaded, allowing the right side tank to fill more than the left side tank. He was unaware of the overload condition. The pilot added that closer monitoring of the helicopter and chemical truck incline, and the final amount of solution being loaded onto the helicopter, might have prevented the accident. The pilot did not report any failures or malfunctions that would have precluded normal operation. ## Factual narrative The pilot reported that he had returned from a prior agricultural application flight. The helicopter chemical tank was loaded with cleaning solution. The pilot stated that he increased engine power and lifted off again. However, immediately after takeoff, the engine and rotor speed began to decrease, and the pilot selected a nearby location for a landing. He flared for touchdown about 10 feet above ground level in order to minimize the forward speed. The helicopter touched down on the rear portion of the landing skids and began to pitch forward. The pilot responded by applying aft cyclic control to prevent the helicopter from nosing over. He subsequently heard a bang and observed debris coming from the aircraft. He shut down the engine and secured the helicopter. A postaccident examination revealed that the main rotor had struck the tailboom resulting in substantial damage to the airframe. The pilot did not report any failures or malfunctions related to the helicopter that occurred prior to the accident. However, the chemical tank was determined to have been loaded with approximately 90 gallons of cleaning solution, instead of the intended 70 gallons. He commented that the aircraft may have been on a slight incline when the solution was loaded, allowing the right side tank to fill more than the left side tank. As a result, he was unaware of the overload condition. The pilot added that closer monitoring of the helicopter and chemical truck incline, and the final amount of solution being loaded onto the helicopter, might have prevented the accident. ## Aircraft - Registration: [N24HM](https://openairdocs.org/deregistered/N24HM-2024-04-26), registration cancelled 2024-04-26, S/N 7688, built 1970 (OpenAirDocs) - Reported make and model: BELL 47G-4A - Registry model: [Bell 47G-4A](https://openairdocs.org/model/bell-47g-4a) (registry code 1181031) (OpenAirDocs) - Registry engine: [Lycoming VO-540 series](https://openairdocs.org/engine/lycoming-vo-540-series) (registry code 41534, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 7688 - Airframe hours: 11153 - Engines: LYCOMING VO-540 SERIES 310 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Rhineland Grain Inc - Registered owner: Rhineland Grain Inc - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, February 26, 2011 - Departed: PVT, Montgomery City, MO - Destination: PVT, Montgomery City, MO ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 27; injuries: none; flight instructor, commercial; instrument ratings: helicopter; medical: class 2, without waivers/limitations; last flight review March 31, 2011; seat: left; flight hours: 1,900 total, 880 in this make and model, 1,810 as pilot in command, 55 in the last 90 days, 40 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 180° at 5 knots - Visibility: 10 statute miles - Lowest ceiling: none ## 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 20110618012569A](https://openairdocs.org/incident/20110618012569A), Jun 18, 2011: Bell 47G-4A, Five Miles West, MO, Substantial damage. Agricultural helicopter N24HM landed on top of the service vehicle to be serviced with fuel and product by the vehicle driver. Fuel was reportedly added to 25… ## Other investigations on N24HM (1) 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 CHI08LA211](https://openairdocs.org/ntsb/CHI08LA211), Jul 24, 2008: Bell 47G-4A (N24HM), Mayville, WI, minor damage, 1 fatal. Probable cause: The pilot's failure to maintain clearance with the rotating rotor blades after he exited the helicopter after landing. ## Docket (2 files) The files NTSB released with the investigation on July 21, 2011, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=80823. 444 KB in all. - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 1, .PDF, 305 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40350731&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Redacted.PDF - Operating Limitations (item 2, .PDF, 139 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40350732&FileExtension=.PDF&FileName=Operating%20Limitations-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.