# NTSB WPR24LA092: Robinson Helicopter R44 II, N422DX, Calexico, CA, December 6, 2023

- Type: NTSB accident investigation
- Classification: Accident · No injuries · Class 4 · Limited · Final report
- Date: December 5, 2023, 17:30 local (Dec 6, 2023, 01:30 UTC)
- Place: Calexico, CA · agricultural field
- Coordinates: 32.691817, -115.43301
- Nearby events: https://openairdocs.org/map.md?lat=32.6918&lon=-115.4330&mi=10
- Phase of flight: [Maneuvering](https://openairdocs.org/ntsb-phases/450) (OpenAirDocs' grouping)
- Defining event: [Maneuvering-low-alt flying: Low altitude operation/event](https://openairdocs.org/ntsb-events/220)
- Highest injury: No injuries
- Injuries: 1 uninjured
- Status: Completed
- Report: Approved by Office Director
- Investigation class: Class 4 - Basic report with no Prelim publish
- NTSB office: Western Pacific Region
- Parties: Federal Aviation Administration
- NTSB case key (mKey): 193822
- NTSB case page: https://web.ntsb.gov/investigations/?ntsbnumber=WPR24LA092
- NTSB report (PDF, downloads): https://data.ntsb.gov/carol-repgen/api/Aviation/ReportMain/GenerateNewestReport/193822/pdf
- NTSB docket: https://data.ntsb.gov/Docket?ProjectID=193822
- Page: https://openairdocs.org/ntsb/WPR24LA092

## Probable cause

The pilot's failure to maintain clearance from power lines during an aerial application flight.

## Findings

NTSB's coded findings; those marked are part of the probable cause.

- [Attention/monitoring: monitoring environment](https://openairdocs.org/ntsb-findings/02021545): Personnel issues › Psychological · Pilot (probable cause); cases with it: [Robinson Helicopter R44 II, 29 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md?model=7640122), [All aircraft, 809 cases](https://openairdocs.org/ntsb-findings/02021545/cases.md)
- [Object/animal/substance: wire](https://openairdocs.org/ntsb-findings/03022032): Environmental issues › Physical environment · Effect on equipment (probable cause); cases with it: [Robinson Helicopter R44 II, 26 cases](https://openairdocs.org/ntsb-findings/03022032/cases.md?model=7640122), [All aircraft, 588 cases](https://openairdocs.org/ntsb-findings/03022032/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: Low altitude operation/event](https://openairdocs.org/ntsb-events/220) (defining event); cases with it: [Robinson Helicopter R44 II, 45 cases](https://openairdocs.org/ntsb-events/220/sequence.md?model=7640122), [All aircraft, 780 cases](https://openairdocs.org/ntsb-events/220/sequence.md)

## Analysis

The pilot was on an aerial application flight and was maneuvering the helicopter at a low altitude. During a decent to a field, the main rotor blade struck a powerline wire. The pilot felt an unusual vibration and performed a precautionary landing. A postflight examination revealed that a main rotor blade sustained substantial damage. No preaccident mechanical failures or malfunctions with the helicopter that would have precluded normal operation were reported.

## Aircraft

- Registration: [N422DX](https://openairdocs.org/aircraft/N422DX), registered now, S/N 12699, built 2009 (OpenAirDocs)
- Reported make and model: ROBINSON HELICOPTER COMPANY R44 II
- Registry model: [Robinson Helicopter R44 II](https://openairdocs.org/model/robinson-helicopter-r44-ii) (registry code 7640122) (OpenAirDocs)
- Registry engine: [Lycoming IO-540-AE1A5](https://openairdocs.org/engine/lycoming-io-540-ae1a5) (registry code 41899, reciprocating) (OpenAirDocs)
- Category: Helicopter
- Serial number: 12699
- Year built: 2009
- Engines: Lycoming IO-540-AE1A5 reciprocating
- Damage: Substantial damage
- Flight: Aerial application, Part 137
- Operator: Merten Aviation Services LLC
- Registered owner: Merten Aviation Services LLC
- Airworthiness certificate: Standard, Normal
- Airport: CXL
- Equipment: Unknown

## Flight crew

As NTSB recorded them. NTSB leaves out names.

- Pilot; age 49; injuries: none; commercial; airplane ratings: single-engine land, multi-engine land; instrument ratings: airplane; medical: class 1, with waivers/limitations

## Weather

- Conditions: Visual (VMC), Day
- Wind: calm
- Visibility: 10 statute miles
- Temperature: 72 °F, dew point 36 °F
- Altimeter: 30.08 inHg
- Observed at: KIPL, 11 nm away
- METAR: METAR KIPL 060053Z AUTO 00000KT 10SM CLR 22/02 A3008 RMK AO2 SLP184 T02170022=

## 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 20231206021039A](https://openairdocs.org/incident/20231206021039A), Dec 6, 2023: Robinson Helicopter Company R44 II, Calexico, CA, Substantial damage. Pilot reported he was performing part 137 spraying operations on multiple agiculture fields. While spraying a fields next to highway 98 in Calexico California…

## Docket (2 files)

The files NTSB released with the investigation on October 22, 2024, on NTSB's docket system: https://data.ntsb.gov/Docket?ProjectID=193822. 165 KB in all.

- Mor - pilot (item 1, PDF, 1 page, 75 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17089019&FileExtension=pdf&FileName=MOR%20-%20Pilot-Rel.pdf
- Accident photo (item 2, PDF, 2 pages, 90 KB): https://data.ntsb.gov/Docket/Document/docBLOB?ID=17085438&FileExtension=pdf&FileName=Accident%20Photo%20092-Rel.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.

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