Airliner Repair, 24/7
Boeing's traveling fix-it team has one goal: Get it airborne.
- By Stephen Joiner
- Air & Space magazine, November 2008
Rick Turnbaugh / Boeing Creative Services
(Page 4 of 6)
Nor is an AOG career designed for your inner nine-to-fiver. “We work two 12-hour shifts, around the clock, seven days a week, until we’re done,” Jim Testin says. “We don’t take holidays. My first 11 years in AOG, I missed Christmas nine times.” He pauses to tally the number of passports he’s filled—six—then shakes his head. “I told my wife I would only do this for three years.”
Still, for an average of just one opening per year, Testin gets as many as 500 applicants. Part of the draw is the mystique. Some of the feats the Boeing AOG operation has performed are commercial aviation legends. In 1988, a 747 aborting a takeoff bellied into a mud flat adjacent to New Delhi airport. Fully 70 percent of the airplane required AOG repair or replacement, at a total cost of $75 million. Then a mechanic, Testin worked 126 days straight in a circus-size tent dubbed the New Delhi Dome. Boeing returned the resurrected jumbo as pristine as one just off the assembly line. Two decades later, it’s still flying.
As it turns out, pulling a 767 in half is a straightforward procedure. “Everything about these aircraft is designed to be taken apart,” mechanic Fred Chadwick says. Before the tail section could be separated from the rest of the fuselage, the towering vertical stabilizer had to be removed. Overhead clearance in the hangar was three feet short, but resourceful AOG mechanics hyper-extended the airliner’s nose gear to tilt the tail down. A gantry crane hoisted the enormous fin to within inches of the rafters, then shuttled it over the airplane and lowered it to a jig on the floor. The tightness of the quarters made it a hold-your-breath procedure that dragged through an entire shift. But AOG tool engineer Jason Lockwood was over his first hurdle.
“When they told me I was going to be on this job, I didn’t sleep for a month,” he admits. Lockwood designs and directs heavy lifting operations. On this repair, heavy lift included the startling act of removing the 48 section—the unwieldy 12,000-pound final fuselage segment that includes the vertical fin, the horizontal stabilizers, and the damaged pressure bulkhead. A 48 separation was a career first for Lockwood. “I’d seen the videos of all the things that can go wrong,” he says.
Just aft of the rear lavatories, the 48 section meets the 46. At a join ring encircling the fuselage, the two fifths of the airplane are held together by 200 bolts—heat-treated, aircraft-grade fasteners (though they look unsettlingly similar to some you might have in a coffee can in the garage). A cable yoke descended from the ceiling crane and attached at five lift points on the tail section. After the crane applied 12,000 pounds of lift, the bolts were removed in a pre-determined sequence. Since the cable tension matched the section’s weight, “theoretically, we should just be able to take out all the bolts and the section will just sit there,” Lockwood says. In practice, determining the suspended segment’s exact center of gravity required some fine-tuning. A few bolts were left loose but threaded as final tweaks were made to the pitch of the yoke. “Once we’ve convinced ourselves it’s in a neutral attitude,” Lockwood says, “we take out those last bolts. Hopefully, it just hangs there.” If it pitches, binds, or pendulums, it could damage the precisely machined mating surfaces of the sections.
With barely a twitch, the fuselage de-mated. The crane backed off, bearing the 48 section, exposing the ruptured bulkhead, and providing mechanics in the now-gaping 46 with a view you hope you never get on your way to the lavatory.
Lockwood slept better thereafter. “It’s actually easier to put it back together than it is to take it apart,” he says.
The intimacy with the way Boeing airplanes dismantle now influences how they’re built. “We put three AOG team members on the 777 design teams, and we’ve followed that up on the 787 and the next-generation 737,” Jim Testin says. Specific design changes were integrated to minimize damage in common incidents and expedite AOG repairs afterward.