# NTSB investigations: Lycoming IO-540-AE1A5, AK

NTSB aviation accident and incident investigations since 1962: the probable cause, findings, aircraft, crew, weather and docket of each, linked to the FAA registry and the FAA’s own reports.

## Latest cases

- [NTSB ANC25LA064](https://openairdocs.org/ntsb/ANC25LA064.md): Robinson Helicopter R44 II · Palmer, AK · Accident · No injuries · Class 4 · Limited · Final report · Jun 30, 2025 · N531AT · Substantial damage
  > The pilot’s diverted attention during takeoff in flat light conditions, which resulted in a loss of visual reference with terrain.
- [NTSB ANC24LA079](https://openairdocs.org/ntsb/ANC24LA079.md): Robinson Helicopter R44 II · Palmer, AK · Accident · Minor injuries · Class 4 · Limited · Final report · Aug 18, 2024 · N783AK · Substantial damage
  > The pilot's failure to follow the operator’s procedure manual and attempted to land at a remote landing zone in high wind conditions. Contributing factor was the pilot’s decision to not conduct a fly over of the landing site to determine wind condition which…
- [NTSB ANC23LA032](https://openairdocs.org/ntsb/ANC23LA032.md): Robinson Helicopter R44 II · Skwentna, AK · Accident · Minor injuries · Class 4 · Limited · Final report · May 9, 2023 · N704T · Substantial damage
  > The pilot's failure to maintain adequate altitude/clearance from terrain while maneuvering in adverse weather conditions, which resulted in a dynamic rollover.
- [NTSB WPR22LA299](https://openairdocs.org/ntsb/WPR22LA299.md): Robinson Helicopter R44 II · Palmer, AK · Accident · Minor injuries · Class 4 · Limited · Final report · Aug 11, 2022 · N987WH · Substantial damage
  > The pilot’s failure to maintain lateral control during an off-field landing, which resulted in loss of control and an impact with terrain.
- [NTSB ANC22LA001](https://openairdocs.org/ntsb/ANC22LA001.md): Robinson Helicopter R44 II · Palmer, AK · Accident · No injuries · Class 4 · Limited · Final report · Oct 10, 2021 · N555EL · 2 aircraft · Substantial damage
  > The unmanned aircraft pilot’s failure to yield the right of way to the helicopter.
- [NTSB GAA19CA531](https://openairdocs.org/ntsb/GAA19CA531.md): Robinson R44 · Nuiqsut, AK · Accident · No injuries · Data collection · Final report · Sep 6, 2019 · N447PA · Substantial damage
  > The pilot's improper decision to land downwind from unsecured debris, which resulted in the helicopter’s main rotor disk ingesting foreign objects.
- [NTSB GAA18CA534](https://openairdocs.org/ntsb/GAA18CA534.md): Robinson R44 · Girdwood, AK · Accident · No injuries · Data collection · Final report · Aug 30, 2018 · N99645 · Substantial damage
  > The fisherman's fishing rod striking the helicopter’s rotating main rotor disk during loading.
- [NTSB ANC17LA040](https://openairdocs.org/ntsb/ANC17LA040.md): Robinson Helicopter R44 · Solomon, AK · Accident · No injuries · Class 3 · Limited · Final report · Aug 3, 2017 · N4138M · Substantial damage
  > The pilot's failure to maintain adequate altitude above water, and his loss of situational awareness, which resulted in an inadvertent descent and collision with water.
- [NTSB ANC16IA013](https://openairdocs.org/ntsb/ANC16IA013.md): Robinson Helicopter R44 II · Anchorage, AK · Incident · No injuries · Incident investigation · Final report · Jan 7, 2016 · N395CE · No damage
  > The overhaul facility's improper and excessive use of an approved lubricant during overhaul of the fuel injection servo, which resulted in a disruption of fuel flow and a total loss of engine power.
- [NTSB ANC16LA010](https://openairdocs.org/ntsb/ANC16LA010.md): Robinson Helicopter R44 II · Valdez, AK · Accident · No injuries · Limited investigation · Final report · Dec 16, 2015 · N255VS · Substantial damage
  > The overhaul facility’s improper and excessive use of an approved lubricant during overhaul of the fuel injection servo, which resulted in a disruption of fuel flow and a total loss of engine power.
- [NTSB ANC12CA018](https://openairdocs.org/ntsb/ANC12CA018.md): Robinson Helicopter R44 II · Beluga, AK · Accident · No injuries · Data collection · Final report · Jan 21, 2012 · N4510T · Substantial damage
  > Ground personnel's movement of cargo in windy conditions, which allowed a previously secured cargo sack to blow into the main rotor blades.
- [NTSB ANC09LA098](https://openairdocs.org/ntsb/ANC09LA098.md): Robinson Helicopter R44 II · Central, AK · Accident · No injuries · Limited investigation · Final report · Sep 7, 2009 · N4186Y · Substantial damage
  > The pilot’s failure to maintain control of the helicopter after an in-flight encounter with a downdraft while landing. Contributing to the accident was the pilot’s inadequate evaluation of wind conditions.

## The whole list in SQL

Runs in DuckDB 1.2 or later on the release's Parquet files over HTTPS:

```sql
SELECT c."ntsbNumber", c."eventDate", c."eventType", c."eventCity", c."eventStateOrRegion", a.n_number, a."aircraftMake", a."aircraftModel", c."highestInjuryLevel", c."totalFatal", c."completionStatus", c.report_url
FROM 'https://openairdocs.org/data/latest/ntsb_case_detail.parquet' c LEFT JOIN 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' a ON a.case_mkey = c."mKey" AND a.position = 1
WHERE c."eventStateOrRegion" = 'AK' AND c."eventCountry" = 'USA'
  AND c."mKey" IN (SELECT x.case_mkey FROM 'https://openairdocs.org/data/latest/ntsb_aircrafts.parquet' x WHERE x.engine_model_code IN ('41899'))
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb?engine=41899&state=AK

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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.