Jim Testin, director of Airliner repair services at the Boeing factory in Everett, Washington, made a prediction in July 2007 based on 27 years of experience. “I can tell you this: Something will always happen on Christmas Eve,” he said with the certainty of a man who has missed many family gatherings.

Five months later, on the night of December 24, a tow tractor pushed a Boeing 767 away from the gate at a busy European airport. And pushed. (Air & Space agreed not to publish the name of the airline or any location.) Passengers heard “a very loud noise” and were invited to disembark via roll-away stairs. An ocean and a continent away, at Boeing’s Commercial Airplanes Operations Center in Seattle, an immense video screen displayed the status of the airliner shoved tail-first into a 14-foot blast-diversion fence. It was officially AOG—Airplane On Ground. For an airline with tickets to sell, that is exactly where you don’t want an airplane that can earn more than $200,000 a day.

From the dents and dings incurred on crowded taxiways to a jumbo jet bobbing in a Tahitian lagoon, Boeing AOG teams have seen and repaired it all. On call 24/7/365, ready to go anywhere around the world, Jim Testin’s quick responders keep over 12,000 extravagantly complex airliners airborne.

“We’re not bashful about promoting our ability to do that,” he says. “When we have a product that’s down and losing revenue, our number-one thing is to get that plane back into service.”

The Boeing team isn’t called in for everything. Airlines have incidents every day, Testin says, and most airport ground crews can handle routine repairs—a window cracked by a bird, a component failing calibration. An AOG intervention is required for the big things: an airplane off the end of a runway, landing gear accidentally retracted, a flaming tail drag, two 150-ton behemoths kissing wingtips on the ramp.

The AOG team is the most expensive roadside service on the planet. One call activates hundreds of people on a single wavelength: urgency. “I’ve been on calls where I could still hear the sirens of the emergency equipment in the background,” Testin says. Another aircraft might be rushed out of routine maintenance or temporarily diverted from another route to fill in for a disabled airliner. But in the house of cards that is today’s airline schedule, yanking even one aircraft from service can cause delays and cancellations.

From an office complex secluded behind tall evergreens on the Duwamish River, the Seattle operations center keeps tabs on Boeing airliners grounded around the world. “In a hospital analogy, this is the emergency room,” says center director Bruce Rund. It looks more like a downsized mission control. Concentric rows of consoles and monitors accommodate 30 controllers, project leaders, and engineers. On a 30-foot-wide video display, the sunrise is tracked across a world map in one screen. In another, blue icons representing AOGs in progress advance along a timeline, turning yellow, then red, as they approach the center’s deadline for action within 24 hours. Controllers conduct telephone triage to establish the severity of each situation and whether the airline wants a permanent repair or a temporary fix that will get the aircraft home. “We need to know quickly: How AOG are you?” Rund says. “Are you sitting in a gate with passengers loaded, or is this problem something you found during an overnight inspection?” The center defines an AOG as any incident requiring a response in less than 24 hours. But when carriers major and minor queue for critical care, everybody knows who goes to the head of the line: “Whoever’s got passengers on board,” Rund says. “It’s understood throughout the industry that we always look at those scenarios first.”

Rund’s staff takes 125 calls a day, and by the time an airline calls, it’s usually tried everything it can to fix a problem itself. The heavy morning departures in Europe and the afternoon rush in the Middle East create problems that show up during Seattle’s witching hours. “It gets really interesting in here when it’s 2 a.m. and we’re the only game in town,” Rund says.

And increasingly they are. As airlines downsize workforces, a busted airplane far from its corporate hub may not be swarmed by a phalanx of mechanics in company jumpsuits. Sometimes, says Rund, “There’s one avionics guy with a screwdriver.”

Owners of damaged airliners occasionally call with a one-item wish list. “They just want to know if they can fly the plane without doing anything,” Rund says. He cites an airline maintenance director pressing for flight approval after sustaining a hammering in a hailstorm. Boeing engineers determined that wing components were damaged beyond limits. Ten minutes of a carefully worded reality check, plus an offer to rush replacement parts to the site, persuaded the impatient carrier to fix instead of fly. “Part of our job is to be the voice of reason,” Rund says.