Four Air Force Special Operators on a spy mission over east Africa died when their U-28 plane crashed as it was returning to Camp Lemonnier, Djibouti. It’s another reminder of the hidden costs of the U.S.’ expanding shadow wars in Africa.

Two captains, Ryan P. Hall and Nicholas F. Whitlock, Lt. Justin J. Wilkens and Senior Airman Julian S. Scholten, died in the crash. A spokeswoman for their home station, Hurlburt Field in Florida, said there was “no indication of enemy fire” causing their deaths.

The spokeswoman, Amy Oliver, confirmed that the crew of the single-engine U-28 had been on a mission that “had to do with ISR” — that is, intelligence, surveillance and reconnaissance for special operations forces on the ground. The U-28 is a small, retrofitted commercial plane that looks indistinguishable from a civilian plane to the naked eye, especially from high in the air.

As the plane returned to Camp Lemonnier, a frequent hub for special operations in pursuit of terrorists in east Africa, “the tower saw smoke coming from the aircraft.” There was no visual identification into the cause of the crash, which Oliver said was still under investigation.

Nor did Oliver specify where the mission occurred. But special operations forces have increased their activity in east Africa significantly in recent years, particularly in Somalia, where on January 24, they pulled off a dramatic hostage rescue deep inside the country. There is another American still held hostage in Somalia, the author Michael Scott Moore, but it was unclear whether the intelligence mission the four elite airmen completed had anything to do with Moore.

A spokeswoman for U.S. Africa Command, Nicole Dalrymple, told Danger Room on Monday that she would check to see what information she could release about the four airmen’s last mission. We’ll update this post as more info becomes available.

Their plane, a U-28, is a tricked-out version of a Pilatus PC-12 turboprop. Similar to the small, commercial piloted planes converted into flying spies by the military’s Project Liberty program, the U-28 carries a suite of sensors and cameras to scout for special operators on the ground. It also doesn’t need a long runway — in fact, it’s able to land on dirt and grass — increasing its appeal for unconventional forces.

Oliver said the airmen hadn’t been at Lemonnier for very long. Air Force special operations deployments typically last two months, she said. But like many of their fellow elite troops, the four men who died had served multiple tours: this was Hall’s seventh deployment, Whitlock’s fifth, Wilkens’ third and Scholten’s third.

The crash actually occurred on Saturday, but the Defense Department deferred the announcement until Monday morning, a typical delay pending notification of the victims’ families. The deaths were announced as “four airmen who were supporting Operation Enduring Freedom,” the military designation for the Afghanistan war, although the crash occurred thousands of miles from Afghanistan; in the past, troops who’ve died in places like Bahrain have been similarly listed as supporting the Afghanistan war.

Photo: U.S. Air Force