# NTSB investigations: Lycoming IO-540 series, MT

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 WPR26LA020](https://openairdocs.org/ntsb/WPR26LA020.md): Piper PA-23-250 · Condon, MT · Accident · 3 fatal · Class 3 · Limited · Preliminary report · Oct 17, 2025 · N2345R · Substantial damage
  > On October 17, 2025, about 1615 mountain daylight time, a Piper PA-23-250, N2345R, was substantially damaged when it was involved in an accident near Condon, Montana. The pilot and two passengers were fatally injured. The airplane was operated as a Title 14…
- [NTSB WPR17LA168](https://openairdocs.org/ntsb/WPR17LA168.md): Robinson Helicopter R44 II · Lake Sutherlin, MT · Accident · No injuries · Limited investigation · Final report · Jul 25, 2017 · N233JD · Substantial damage
  > The pilot’s transition into an out-of-ground-effect hover in high-density altitude conditions that exceeded the helicopter’s performance capabilities, which resulted in loss of rotor rpm.
- [NTSB WPR17LA143](https://openairdocs.org/ntsb/WPR17LA143.md): Robinson Helicopter R44 II · Ronan, MT · Accident · Serious injuries · Limited investigation · Final report · Jul 6, 2017 · N442DR · Substantial damage
  > The pilot's failure to maintain adequate airspeed, which resulted in a loss of tail rotor effectiveness during a low-altitude orbiting maneuver and a subsequent hard landing.
- [NTSB WPR13CA403](https://openairdocs.org/ntsb/WPR13CA403.md): Maule M-7-260C · Nashua, MT · Accident · No injuries · Data collection · Final report · Sep 8, 2013 · N5515V · Substantial damage
  > The pilot's failure to maintain clearance from a berm during the takeoff, which resulted in a loss of directional control.
- [NTSB WPR13FA343](https://openairdocs.org/ntsb/WPR13FA343.md): Robinson Helicopter R44 II · Thompson Falls, MT · Accident · 1 fatal · Field investigation · Final report · Jul 27, 2013 · N25WH · Substantial damage
  > The pilot's failure to maintain helicopter control while operating in conditions conducive to a loss of tail rotor effectiveness.
- [NTSB CEN10LA496](https://openairdocs.org/ntsb/CEN10LA496.md): Cessna 182T · Mosby, MT · Accident · No injuries · Limited investigation · Final report · Aug 18, 2010 · N1142U · Substantial damage
  > A partial loss of engine power for undetermined reasons during an en route climb.
- [NTSB LAX08CA182](https://openairdocs.org/ntsb/LAX08CA182.md): Robinson R44 II · Missoula, MT · Accident · Minor injuries · Data collection · Final report · Jun 14, 2008 · N272SW · Destroyed
  > The student's inadvertent control interference, which the flight instructor was unable to overcome. A contributing factor was the instructor's poor crew coordination in his failure to verbally command the student to relinquish the controls and his inadequate…
- [NTSB LAX08LA154](https://openairdocs.org/ntsb/LAX08LA154.md): Maule MX-7-235 · Boulder, MT · Accident · 1 fatal · Limited investigation · Final report · May 23, 2008 · N5657Y · Substantial damage
  > The pilot's decision to continue flight at low altitude in instrument weather conditions and his failure to maintain clearance from a power line. Contributing to the accident were low cloud and visibility conditions.
- [NTSB SEA07LA114](https://openairdocs.org/ntsb/SEA07LA114.md): Britten-Norman BN-2A-20 · Hamilton, MT · Accident · Minor injuries · Limited investigation · Final report · Apr 28, 2007 · N634MA · Substantial damage
  > The loss of power in one engine, for undetermined reasons, soon after establishing the takeoff departure climb. Factors include rough/uneven terrain.
- [NTSB SEA06CA191](https://openairdocs.org/ntsb/SEA06CA191.md): Maule M-6-235 · Ronan, MT · Accident · No injuries · Data collection · Final report · Sep 29, 2006 · N9918T · Substantial damage
  > The pilot's failure to maintain directional control during the landing roll in the tailwheel-equipped aircraft. A swale (sunken area) between the runway and the taxiway was a factor.
- [NTSB SEA80DTA11](https://openairdocs.org/ntsb/SEA80DTA11.md): Callair A-9 · Bloomfield, MT · Accident · No injuries · Closed · Apr 24, 1980 · N8246H · Substantial damage
- [NTSB SEA80FTI06](https://openairdocs.org/ntsb/SEA80FTI06.md): Piper PA-24 · Havre, MT · Accident · No injuries · Closed · Mar 30, 1980 · N8820P · Substantial damage

## 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" = 'MT' 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 ('41530', '41585'))
ORDER BY c."eventDate" DESC, c."ntsbNumber" DESC
```

This list as a web page: https://openairdocs.org/ntsb?engine=41530&state=MT

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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.