# NTSB CHI01LA259: Bell 47G-2, N440TG, Blooming Prairi, MN, August 5, 2001 - Type: NTSB accident investigation - Classification: Accident · No injuries · Limited investigation · Final report - Date: August 4, 2001, 19:15 local (Aug 5, 2001, 00:15 UTC) - Place: Blooming Prairi, MN - Coordinates: 43.859687, -93.050003 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=43.8597&lon=-93.0500&mi=10 - Phase of flight: [Enroute](https://openairdocs.org/ntsb-phases/400) (OpenAirDocs' grouping) - Highest injury: No injuries - Injuries: 2 uninjured - Status: Completed, report January 16, 2003 - Report: Approved by Office Director - Parties: Federal Aviation Administration - NTSB case key (mKey): 52969 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CHI01LA259 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/52969/pdf - Page: https://openairdocs.org/ntsb/CHI01LA259 ## Probable cause The reported loss of engine power for undetermined reasons during a the cruise portion of a CFR part 137 observation, and the pilot not following the height/velocity charts data. ## Sequence of events In NTSB's coding before 2008 (https://www.ntsb.gov/GILS/Documents/codman.pdf). - Loss of engine power, cruise - reason for occurrence undetermined (cause) - weather condition - carburetor icing conditions - Forced landing, descent - emergency - weather condition - high density altitude - height/velocity curve - not followed, pilot in command (cause) - autorotation - performed, pilot in command - procedures/directives - not followed, pilot in command - In flight collision with terrain/water, emergency descent/landing ## Analysis The helicopter sustained substantial damage on impact with terrain during a forced landing following an in-flight loss of engine power while performing an operation under 14 CFR part 137. The pilot and passenger sustained no injuries. The pilot reported, "Observation executed at 75' AGL [above ground level] and below 20 mph. Engine loss of power. Autorotation to neighboring soybean field. Damage to aircraft. No Injuries. Aircraft had 20 gallons of fuel and no agricultural treatment products on board." The accident engine ran during a test run. The temperature was 29 degrees C and the dew point was 23 degrees C. At 1915, the calculated density altitude was 3,025 feet. The temperature and dew point were plotted on the carburetor icing chart and their intersection fell in the serious icing - descent power area. The observation airspeed and altitude were plotted on height/velocity chart and their intersection falls in the avoid continuous operation area of the chart. The Bell 47G-2 flight manual stated, "PASSENGERS PROHIBITED DURING SPECIAL PURPOSE OPERATIONS. Persons other than minimum crew necessary for the purpose involved shall not be carried during special purpose operations in restricted category aircraft." FAA regulation section 91.313 stated' "Restricted category civil aircraft: Operating limitations. ... (d) No person may be carried on a restricted category civil aircraft unless that person- (1) Is a flight crewmember; (2) Is a flight crewmember trainee; (3) Performs an essential function in connection with a special purpose operation for which the aircraft is certificated; or (4) Is necessary to accomplish the work activity directly associated with that special purpose." ## Factual narrative On August 4, 2001, about 1915 central daylight time, a Bell 47G-2, N440TG, piloted by a commercial pilot, sustained substantial damage on impact with terrain following an in-flight loss of engine power while maneuvering near Blooming Prairie, Minnesota. The observation flight was operating under 14 CFR part 137. Visual meteorological conditions prevailed at the time of the accident. No flight plan was on file. The pilot sustained no injuries. The local flight departed from a trailer in a field near Blooming Prairie, Minnesota, at time unknown and was maneuvering at the time of the accident. The pilot reported: Part 137 operation. Observation of sweetcorn field. Observation executed at 75' AGL [above ground level] and below 20 mph. Engine loss of power. Autorotation to neighboring soybean field. Damage to aircraft. No Injuries. Aircraft had 20 gallons of fuel and no agricultural treatment products on board. The pilot also reported a passenger was onboard during the flight. After the accident, Federal Aviation Administration (FAA) Inspectors observed the operator test run the accident engine. The engine was observed to "function properly." At 1915, the Owatonna Degner Regional Airport (OWA) weather was: Wind 160 degrees at 9 knots; sky condition clear; temperature 29 degrees C; dew point 23 degrees C; altimeter 29.96 inches of mercury. At 1915, the calculated density altitude at OWA was 3,025 feet. A copy of a Transport Canada Carburetor Icing chart was reviewed. The temperature and dew point were plotted on that chart and their intersection falls in the serious icing - descent power area of the chart. See appended icing chart. A Bell 47G-2 helicopter airspeed vs. altitude limitations chart was reviewed. The observation airspeed and altitude were plotted on that chart and their intersection falls in the avoid continuous operation area of the chart. See appended airspeed vs. altitude limitations chart. The Bell 47G-2 flight manual stated: PASSENGERS PROHIBITED DURING SPECIAL PURPOSE OPERATIONS. Persons other than minimum crew necessary for the purpose involved shall not be carried during special purpose operations in restricted category aircraft. FAA regulation section 91.313 stated: Restricted category civil aircraft: Operating limitations. ... (d) No person may be carried on a restricted category civil aircraft unless that person- (1) Is a flight crewmember; (2) Is a flight crewmember trainee; (3) Performs an essential function in connection with a special purpose operation for which the aircraft is certificated; or (4) Is necessary to accomplish the work activity directly associated with that special purpose. ## Aircraft - Registration: [N440TG](https://openairdocs.org/aircraft/N440TG), registered now, S/N 2245, built 1959 (OpenAirDocs) - Reported make and model: Bell 47G-2 - Registry model: [Bell 47G-2](https://openairdocs.org/model/bell-47g-2) (registry code 1181008) (OpenAirDocs) - Registry engine: [Lycoming VO-435 series](https://openairdocs.org/engine/lycoming-vo-435-series) (registry code 41525, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 2245 - Airframe hours: 13180 - Engines: Lycoming VO-435 260 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial observation, Part 137 - Operator: Scotts Helicopter Services Inc - Registered owner: Scotts Helicopter Services Inc - Airworthiness certificate: Special, Restricted (Special) - Last inspection: Annual, April 18, 2001, 90 hours before - Departed: Blooming Prairi, MN ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 37; injuries: none; commercial; airplane ratings: single-engine land; medical: class 2, valid medical--w/ waivers/lim; last flight review April 14, 2000; seat: center; flight hours: 2,415 total, 2,315 in this make and model, 2,415 as pilot in command, 300 in the last 90 days, 125 in the last 30 days, 16 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 160° at 9 knots - Lowest ceiling: none - Temperature: 84 °F, dew point 73 °F - Altimeter: 29.95 inHg - Observed at: OWA, 10 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 20010804023929A](https://openairdocs.org/incident/20010804023929A), Aug 4, 2001: Bell 47G2, Owatona, MN, No damage. (-23) Pilot states that the engine lost power while performing a field observation at approximately 75' AGL. Pilot executed an autorotation to a nearby soybean… ## Other investigations on N440TG (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 CHI88DEM05](https://openairdocs.org/ntsb/CHI88DEM05), May 31, 1988: Bell 47G-2A (N440TG), Midland, MI, 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.