# NTSB CEN19LA230: Robinson R44, N459TA, Ida Grove, IA, July 21, 2019 - Type: NTSB accident investigation - Classification: Accident · Minor injuries · Class 3 · Limited · Final report - Date: July 21, 2019, 08:45 local (13:45 UTC) - Place: Ida Grove, IA - Coordinates: 42.340831, -95.538055 (estimated) - Nearby events: https://openairdocs.org/map.md?lat=42.3408&lon=-95.5381&mi=10 - Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping) - Defining event: [Maneuvering-low-alt flying: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) - Highest injury: Minor injuries - Injuries: 1 minor - Status: Completed - Report: Approved by Office Director - Investigation class: Class 3 - NTSB office: Central Region - Parties: FAA Des Moines FSDO, Robinson Helicopter Company - SAIBs cited in the narratives: [SAIB CE-09-35](https://openairdocs.org/saib/CE-09-35) (OpenAirDocs) - NTSB case key (mKey): 99895 - NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=CEN19LA230 - NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/99895/pdf - NTSB docket: https://data.ntsb.gov/Docket?ProjectID=99895 - Page: https://openairdocs.org/ntsb/CEN19LA230 ## Probable cause A total loss of engine power during an aerial application flight for undetermined reasons. ## Findings NTSB's coded findings; those marked are part of the probable cause. - [Not determined](https://openairdocs.org/ntsb-findings/05000000): Not determined › Not determined · Unknown/Not determined (probable cause); cases with it: [Robinson Helicopter R44, 11 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md?model=7640120), [All aircraft, 2,247 cases](https://openairdocs.org/ntsb-findings/05000000/cases.md) ## Sequence of events The events NTSB coded, in order, by phase of flight. The defining event best describes what happened. - [Maneuvering-low-alt flying: Loss of engine power (total)](https://openairdocs.org/ntsb-events/341) (defining event); cases with it: [Robinson Helicopter R44, 5 cases](https://openairdocs.org/ntsb-events/341/sequence.md?model=7640120), [All aircraft, 3,820 cases](https://openairdocs.org/ntsb-events/341/sequence.md) - [Autorotation: Attempted remediation/recovery](https://openairdocs.org/ntsb-events/060); cases with it: [Robinson Helicopter R44, 7 cases](https://openairdocs.org/ntsb-events/060/sequence.md?model=7640120), [All aircraft, 1,422 cases](https://openairdocs.org/ntsb-events/060/sequence.md) - [Autorotation: Off-field or emergency landing](https://openairdocs.org/ntsb-events/440); cases with it: [Robinson Helicopter R44, 13 cases](https://openairdocs.org/ntsb-events/440/sequence.md?model=7640120), [All aircraft, 3,365 cases](https://openairdocs.org/ntsb-events/440/sequence.md) - [Autorotation: Hard landing](https://openairdocs.org/ntsb-events/092); cases with it: [Robinson Helicopter R44, 16 cases](https://openairdocs.org/ntsb-events/092/sequence.md?model=7640120), [All aircraft, 2,102 cases](https://openairdocs.org/ntsb-events/092/sequence.md) - [Autorotation: Collision with terr/obj (non-CFIT) ](https://openairdocs.org/ntsb-events/470); cases with it: [Robinson Helicopter R44, 56 cases](https://openairdocs.org/ntsb-events/470/sequence.md?model=7640120), [All aircraft, 10,189 cases](https://openairdocs.org/ntsb-events/470/sequence.md) ## Analysis The commercial pilot of the helicopter was performing an aerial application flight when he noted the engine rpm below "half" and dropping along with the main rotor rpm. The pilot reduced the collective and attempted a high hovering autorotation. Due to the lack of airspeed and altitude, the helicopter impacted a bean field "very hard." The pilot reported that the engine was not operating when the helicopter came to rest on its left side. The pilot reported that he was paying close attention to the carburetor heat temperature during the flight, as he had the carburetor heat lever pulled out "a little over half" and he kept the needle out of the yellow arc depicted on the carburetor temperature gauge. A postaccident examination of the airframe and engine found no preimpact mechanical malfunctions or failures that would have precluded normal operation, and the helicopter had adequate fuel onboard at the time of the accident. The temperature and dew point at the time of the accident were conducive to the formation of serious carburetor icing at glide power settings. However, given that the pilot was monitoring the carburetor temperature gauge, it is unlikely that the loss of engine power was due to carburetor ice. The reason for the loss of engine power could not be determined based on the available information. ## Factual narrative On July 21, 2019, about 0845 central daylight time, a Robinson R-44 (Raven I), N459TA, sustained substantial damage when it was involved in an accident near Ida Grove, Iowa. The commercial pilot sustained minor injuries. The helicopter was operated as a Title 14 Code of Federal Regulations Part 137 aerial application flight. The pilot reported the purpose of the flight was to apply fungicide to a field. The pilot was spraying the field with north to south and south to north swath runs. Due to the location of various obstacles near the field, the pilot was conducting teardrop turns to safely facilitate the swath runs. The obstacles near the field included trees, power line poles, and power lines. At the end of his second north to south swath run, the helicopter came out of the field and executed a "gentle" tear drop turn to the left going about 25 kts. The pilot estimated his altitude at the time to be about one and half to two "telephone pole" lengths high. Once the turn was completed and the pilot was approaching the target field, the helicopter yawed "hard" to the left. The pilot attempted to correct the yaw with right tail rotor pedal input and the low rotor rpm light and horn activated. The pilot observed the engine rpm below "half" and dropping, along with the main rotor rpm, which had a "good split." The pilot reduced the collective and attempted a high hovering autorotation. Due to the lack of airspeed and altitude, the pilot reported the helicopter impacted a bean field "very hard." The pilot reported the engine was not operating when the helicopter came to rest on its left side. The pilot was able to egress from the helicopter without further incident. At the time of the accident, the pilot reported the temperature was about 64° F and the wind condition originated from about 030°, at 6 kts. He reported he was paying close attention to the carburetor heat temperature during the flight, as he had the carburetor heat lever pulled out "a little over half" and he kept the needle out of the yellow arc depicted on the carburetor temperature gauge. For the engine power settings with the collective for the swath runs, he reported he was below 15 inches of manifold pressure as he would come out of the field, and once he would level out, he would never exceed 21 inches of manifold pressure. About 15 minutes prior to the accident, a loader from the operator reported that he loaded the helicopter with 30 gallons of water, 105 ounces (0.82 gallons) of AFrame fungicide, and 5 gallons of 100 low lead fuel. The helicopter sustained substantial damage to the main rotor system, the fuselage, the tail boom, and the tail rotor system. A postaccident examination of the airframe and engine by a Federal Aviation Administration (FAA) aviation safety inspector (ASI) found no preimpact mechanical malfunctions or failures that would have precluded normal operation. The FAA ASI additionally reported that photographs from law enforcement officials at the accidentsite showed the carburetor heat was on at the time of the impact. The reported temperature and dewpoint at the time of the accident indicated a probability of serious icing conditions at glide power settings per the carburetor icing probability graph from the FAA Special Airworthiness Information Bulletin CE-09-35 Carburetor Icing Prevention. The helicopter was equipped with a carburetor heat assist device. The Robinson R-44 Pilot's Operating Handbook discusses this device and states in part: The carburetor heat assist correlates application of carburetor heat with changes in collective setting to reduce pilot workload. Lowering collective mechanically adds heat and raising collective reduces heat. A friction clutch allows the pilot to override the system and increase or decrease heat as required. ## Aircraft - Registration: [N459TA](https://openairdocs.org/deregistered/N459TA-2019-11-15), registration cancelled 2019-11-15, S/N 1514, built 2005 (OpenAirDocs) - Reported make and model: Robinson R44 (Raven I) - Registry model: [Robinson Helicopter R44](https://openairdocs.org/model/robinson-helicopter-r44) (registry code 7640120) (OpenAirDocs) - Registry engine: [Lycoming O-540-F1B5](https://openairdocs.org/engine/lycoming-o-540-f1b5) (registry code 42353, reciprocating) (OpenAirDocs) - Category: Helicopter - Serial number: 1514 - Year built: 2005 - Airframe hours: 1463.5 - Engines: Lycoming O-540-F1B5 300 horsepower reciprocating - Damage: Substantial damage - Flight: Aerial application, Part 137 - Operator: Mid-West Helicopter, LLC - Registered owner: Mid-West Helicopter, LLC - Airworthiness certificate: Standard, Normal - Last inspection: Unknown, May 24, 2019 - Departed: IDG, Ida Grove, IA - Destination: IDG, Ida Grove, IA - Equipment: None ## Flight crew As NTSB recorded them. NTSB leaves out names. - Pilot; age 41; injuries: minor; commercial, flight instructor; instrument ratings: helicopter; medical: class 2, waiver time limited special; last flight review March 27, 2018; seat: right; restraint: 3-point; flight hours: 1,204 total, 676 in this make and model, 1,058 as pilot in command, 53 in the last 90 days, 12 in the last 30 days, 3 in the last 24 hours ## Weather - Conditions: Visual (VMC), Day - Wind: 60° at 8 knots, gusting 13 - Visibility: 10 statute miles - Lowest ceiling: 6,000 ft overcast - Temperature: 64 °F, dew point 64 °F - Altimeter: 30.03 inHg - Observed at: KSLB, 20 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 20190721015129A](https://openairdocs.org/incident/20190721015129A), Jul 21, 2019: Robinson Helicopter R44, Ida Grove, IA, Substantial damage. Maneuvering through a shallow right turn, followed by left teardrop turn and alignment of next spray run. The pilot experienced loss of tail rotor control and… ## Docket (5 files) The files NTSB released with the investigation on August 7, 2020, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=99895. 7.0 MB in all. - Accident Photographs (item 1, .PDF, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485965&FileExtension=.PDF&FileName=Accident%20Photographs%20-Master.PDF - Pilot/Operator Aircraft Accident Report, NTSB Form 6120.1 (item 2, .PDF, 3.9 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485966&FileExtension=.PDF&FileName=Pilot%2FOperator%20Aircraft%20Accident%20Report,%20NTSB%20Form%206120.1-Master.PDF - Pilot Documents (item 3, .PDF, 131 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485967&FileExtension=.PDF&FileName=Pilot%20Documents%20-Master.PDF - FAA Documents (item 4, .PDF, 583 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485968&FileExtension=.PDF&FileName=FAA%20Documents%20-Master.PDF - NTSB Party Member Form - Robinson Helicopter Company (item 5, .PDF, 1.2 MB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=40485969&FileExtension=.PDF&FileName=NTSB%20Party%20Member%20Form%20-%20Robinson%20Helicopter%20Company%20-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.