ALBUQUERQE, N.M. – Federal investigators on Wednesday were trying to piece together what caused a medical transport plane to crash on the Navajo Nation in northern Arizona, killing the four people on board and leaving the medical community in neighboring New Mexico heartbroken.

The two pilots, flight nurse and paramedic who were onboard were based out of Albuquerque and had worked with hospitals throughout the area. While authorities had yet to release their names, colleagues and friends shared condolences and prayers on social media.

Many shared details about the crew’s dedication to patients and the incredible void left by the tragedy.

The crew was on its way to pick up a patient from the federal Indian Health Service hospital in Chinle when the plane crashed near the airport there, Navajo authorities said. The plan was to return to Albuquerque.

The Beechcraft King Air 300 was owned by CSI Aviation. The company said in a statement that it was devastated and that the four were more than just colleagues.

“Their courage, care, and dedication will never be forgotten,” the company said. “Our hearts are with their families, friends, and loved ones.”

According to CSI Aviation’s website, the nationally accredited carrier never had an accident or incident and never had any FAA sanctions. It provides medical flights in Texas, New Mexico, Arizona, Colorado and South Dakota.

Medical transports by air from the Navajo Nation are common because most hospitals are small and do not offer advanced or trauma care. The Chinle airport is one of a handful of airports that the tribe owns and operates on the vast 27,000-square-mile (70,000-square-kilometer) reservation that stretches into Arizona, New Mexico and Utah — the largest land base of any Native American tribe.

Aviation safety consultant Jeff Guzzetti, who is a former NTSB and FAA crash investigator, said it’s difficult to say what caused this crash in a remote area like Chinle because so few details are readily available.

The high altitude of Chinle, which sits just over 5,500 feet above sea level, and the high temperatures Tuesday around 95 degrees can make it harder for a plane to get the lift it needs to fly, but Guzzetti said that is usually more of an issue at takeoff — rather than landing — and this kind of Beechcraft Super King Air plane has plenty of power with its twin turboprop engines.

The plane also shouldn’t have been overweight because it had already burned off fuel during its flight and hadn’t yet picked up the patient.

At the time the plane was trying to land, the wind was gusting up to 28 knots, which could have made landing difficult at the Chinle airport, which has a narrow, 60-foot-wide runway.

“Gusting crosswinds to 28 knots can make things a little bit challenging,” Guzzetti said. “The winds might have been an issue.”

Aside from examining the wreckage, NTSB investigators will be reviewing flight data, any air traffic control communications, aircraft maintenance records and weather conditions at the time as they try to determine what caused the crash.

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AP Transportation Writer Josh Funk reported from Omaha, Nebraska.