The National Transportation Safety Board and the Federal Aviation Administration are investigating the crash of an ultralight aircraft Thursday evening in Russell. Photo by Brian Ferry

WARREN, Pa. — When an aircraft crashes in the United States, the National Transportation Safety Board is the entity tasked with investigating.

The NTSB is conducting an investigation into the crash of an ultralight last Thursday in Pine Grove Township.

“We did open an investigation into this accident on July 14,” NTSB Spokesman Peter Knudson said Monday. “We assigned an investigator to it.”

The agency conducts about 1,200 investigations into aviation accidents each year.

“Thankfully, the majority of these are non-fatal,” Knudson said.

Its resources can be spread pretty thin, so the agency did not put its boots on the ground in Warren County last week.

Knudson said the agency focuses more resources on more serious, including fatal, crashes,

For cases like the crash in Russell, “We rely on the FAA to help us on-scene,” he said.

“A single-engine Flightstar II crashed near Russell, Pa., around 8 p.m. local time July 14,” FAA Public Affairs Specialist Steven Kulm said. “There were two people on board. The FAA is investigating.”

Information about the condition of the pilot, who was taken from the scene by emergency helicopter, is not available.

An investigation results in the determination of the probable cause of the accident, Knudson said.

Exactly when that determination might be passed down depends on the circumstances and complexity of the crash.

According to the NTSB website, the timeline for reporting the results of such an investigation could be long.

“Roughly two weeks after an accident, a preliminary report will be issued,” according to NTSB. “The preliminary report will contain factual information collected on scene. It will not have a cause.”

Depending upon the circumstances of the case, the publication of a probable cause could take “one to two years,” according to the website.