The threat of military personnel sick with COVID-19 and stranded in far-off places brought a parade of Air Force jets to Lincoln recently for an “urgent” series of on-board tests.
The joint U.S. Transportation Command wants to find out which Air Force transport planes are safest to carry infected passengers when the need arises.
So the Air Force flew in six types of aircraft to the Nebraska Air National Guard base at Lincoln Airport, headquarters of the 155th Air Refueling Wing.
There, a team of researchers from the University of Nebraska’s National Strategic Research Institute studied how air moves inside the planes (KC-135, KC-10 and KC-46 tankers, as well as C-5M, C-130J and C-17 transports), both on the ground and in the air.
“We’re conducting this test so we can understand the airflow characteristics within the plane,” Maj. David Sustello, ground liaison for the Air Force’s Air Mobility Command, said in a video interview. “So we can understand whether we can transport infectious passengers from wherever they are to wherever they can get the medical care they need.”
That’s gone from a theoretical need to an urgent one.
On April 10, as the testing wrapped up in Lincoln, a C-17 transport evacuated three U.S. government contractors who had tested positive for the novel coronavirus from Afghanistan to Germany. The three are being observed at a military hospital in Landstuhl, Germany.
The contractors were airlifted inside a containment pod called a self-contained Transport Isolation System, developed by the military after the 2014 Ebola outbreak in Africa. The mission was the first use of the pod outside of training.
But TransCom knew that in case of a larger-scale evacuation, it might need to move more people than the four (or two on stretchers) who can fit in one of the isolation units.
So TransCom leaders decided last month to find out, and find out quickly, whether the Air Mobility Command’s tankers and transports could carry infectious patients without endangering the crew. They described it as a “Joint Urgent Operational Need.”
They got in touch with the research institute, which carries out scientific projects under the sponsorship of the Nebraska-based U.S. Strategic Command. The University of Nebraska Medical Center is among the worldwide leaders in research on infectious diseases.
“They had the most experience with these kind of airflow patterns and biologic aerosols,” Sustello said.
And he knew they could do the work quickly.
“It usually takes months and months to plan an experiment like this. We executed it with two weeks’ notice,” said Dillan Cunningham, the institute’s director of special projects. “It was definitely an extreme turnaround for everyone involved.”
Two years ago, Joshua Santarpia, an associate professor of pathology and microbiology at UNMC, developed a way of circulating tiny fluorescent beads tagged with DNA in an aerosol form.
The beads measure 1 to 3 microns, too small for the human eye to see. (A human hair is about 30 to 100 microns wide.) But Santarpia’s research team can measure them with instruments.
Movement and travel restrictions complicated the experiments, but Sustello said the Air National Guard base in Lincoln proved to be a convenient place to carry them out.
The researchers could get there by car, the planes and their air crews could fly in. The 155th Air Refueling Wing offered ground and logistical support — plus the aircraft and air crew for experiments on the KC-135, which it has used on its missions for years.
The experiments continued from April 4 to 11. Each day, a different aircraft arrived in Lincoln. The scientists climbed on with their aerosol machines, laptop computers and monitoring equipment. Sometimes they wore protective spacesuits.
Each aircraft brings outside air onto the aircraft in a controlled way — commonly, through the engines — and expels air through vents in the floor.
After the beads were released, they were monitored with instruments. Technicians taped off and numbered areas of the floor of the aircraft so they could also take surface measurements. Sometimes they would rearrange partitions in the rear of the aircraft midflight to change the airflow.
“Our hope is to have positive airflow, front to back, throughout the flight,” said Michael Steeme, a member of the Boeing Legacy Tanker Team from Tinker Air Force Base, Oklahoma. “If we can show that airflow, it keeps the air crew up front safe from any virus trying to migrate forward.”
The KC-135s were designed in the late 1950s and built in the early 1960s. Steeme said he has worked on them, in the Air Force and now for Boeing, since 1975.
“Studies like this of where the air flows on the aircraft have never been done before, to the extent that we’re doing them today,” said Jeffrey Sorenson, a mechanical engineer with the KC-135 program office at Tinker.
After hours of work each day aboard the aircraft, the scientists spent their nights studying the data they had gathered.
“After every single test, you had to go back and analyze as much as you can, as fast as you can,” Cunningham said. “Guys were burning the midnight oil.”
This wasn’t the kind of study the Air Force can afford to wait for and then file on a shelf somewhere. Cunningham said the scientists have already given TransCom information that can be put to use quickly.
He wouldn’t disclose their findings, but he did say the experiments proved that sick patients can be carried safely on Air Force planes.