The pilot of a Van's RV-6, a two-seat amateur-built light aircraft12, was killed when the aircraft crashed south of Hamilton, Montana, on Wednesday 4 November 202634. He was the only person on board5. The National Transportation Safety Board (NTSB) is investigating, and its case record lists the aircraft as N691DS and the location as Como, Montana34.

What happened south of Hamilton

Ravalli County Sheriff and Coroner Steve Holton announced the death in a press release6. He said the plane crashed in the Harlan Gulch area east of Highway 93, south of Hamilton54. The investigation began on Wednesday night after a resident reported hearing what could have been an aircraft crash, and the pilot was later reported overdue4. Poor weather, including fog, prevented search aircraft from operating, so the sheriff's office deployed drones, but searchers were unable to track the missing plane74. Searchers could not find the crash site in the dark; deputies and search and rescue members found it on Thursday morning in daylight5.

The pilot was pronounced dead at the scene4. The sheriff's office identified him only as a 43-year-old man from Hamilton and did not release his name pending notification of his family75. "Sheriff Holton extended condolences and prayers for the pilot's family and friends," the sheriff's office said7.

The aircraft: a Van's RV-6

The NTSB record gives the aircraft model as RV-6 and the registration as N691DS3. In the FAA aircraft registry, N691DS is a fixed-wing single-engine aeroplane with a Lycoming O-320 series piston engine, certificated in the experimental category as amateur-built, with an airworthiness date of 7 February 19952. Its registration is listed as valid until 31 March 20322.

The RV-6 was the first Van's design to seat the pilot and passenger next to each other1. The tailwheel RV-6 and the tricycle-gear RV-6A were introduced in 1986, and Van's replaced them with the RV-7 and RV-7A in 20011. According to Van's, more than 2,600 RV-6s have flown1. Under US rules, an amateur-built aircraft is one "the major portion of which has been fabricated and assembled by person(s) who undertook the construction project solely for their own education or recreation"8.

How the NTSB investigation works

The NTSB lists the case, a fatal accident, as investigation WPR27FA033 and records it as ongoing3. No preliminary report or probable cause has been published yet, and the docket for the investigation has not been released39. According to the NTSB, a preliminary report gives a synopsis of the factual information collected during the on-scene phase and is typically available within two weeks of a general aviation accident10. The NTSB does not determine the cause of an accident while at the scene10.

The final report brings together the factual information, the analysis, the findings and the probable cause, and it replaces the preliminary report10. A general aviation accident investigation often requires 12 to 24 months to complete10. Separately, the Ravalli County Coroner's Office will determine the cause and manner of death7.

What has not been released

The authorities have not said where the flight departed from, where it was heading or in which phase of flight the accident happened. A resident reported hearing a possible crash on Wednesday evening74. Neither the sheriff's office nor the NTSB has said what caused the crash43.

For background on how an NTSB investigation into a fatal general aviation accident develops, read our dossier on the PAC 750XL crash in Butler, Missouri. You can also read what it takes to earn a private pilot licence, browse flight schools in the United States or read more safety news.