Four times a week, a fighter jet from California lifts off from Joint Base Lewis-McChord for a rendezvous in the Northwest skies with one of the military's newest machines.
It's a noticeable new routine at JBLM that's meant to help the Air Force test its KC-46 tanker, a jet built by Boeing in King County to replace a third of the military's aging fleet of Cold War-era refueling aircraft.
For JBLM, the job centers on checking whether Boeing's next-generation tankers perform as the company promised when it won a $51 billion contract to build them.
"Lives are at stake, and it's the war-fighters that are depending on it. You need to make sure you're getting it right," said Master Sgt. Justin Suddeth, who photographs the KC-46 in flight from the cockpit of an F-16 Falcon jet a couple times a week.
He's one of several visiting airmen who'll spend time at JBLM over the next 16 months, participating in the KC-46 tests. His images are sent to an Air Force and Boeing team evaluating the KC-46's progress.
"You're taking an aircraft that has never flown, and now you need to walk it through all those steps and build it up," said Suddeth, 36.
So far, the Air Force has sent two F-16s to JBLM from Edwards Air Force Base in California. Other jets likely will pass through, including refueling tankers and A-10 Warthog ground combat support aircraft.
The idea is to see how the KC-46 fares when different kinds of jets attempt to receive fuel from it and to determine how well it flies close to other aircraft.
"It just gets very complicated with these big engineering challenges," said Capt. Sean Richardson, 31, an F-16 pilot visiting JBLM from Edwards Air Force Base.
JBLM set up the visiting crews in an old hangar at the south end of McChord Air Field that once held some of the Air Force's earliest fighter jets, such as the F-86.
Its stalls are too small for the fleet of C-17 Globemaster III cargo jets stationed full-time at McChord, and it's rarely used except when planes visit JBLM for military exercises. It promises to be a busy site through 2016 because of the refueling tests.
The KC-46 tankers fly only out of Boeing International Air Field in south Seattle. The Air Force has not practiced a refueling mission with one of the new machines, but the F-16s at JBLM have trailed it and flown alongside it. The tanker is a refashioned Boeing 767.
"It's big," Suddeth said.
The flights take place all over the Northwest, often in air space designated for military and government training. This week, Richardson flew along the Washington coast and in northeast Washington over to Idaho.
The base has not heard complaints about noise from the visiting jets. They've flown during daylight business hours. Pilots also are not taking off with full-strength afterburners, which could be audible to Lakewood and Tacoma residents.
"We've elected to take off with a quieter profile," Richardson said.