LOS ANGELES — It wasn’t long after the morning sun came up over the Mojave Desert that Sean Byrne noticed a black speck fluttering just above the foothills of the San Gabriel Mountains.

He knew what it was, as did the other workers from Northrop Grumman Corp. surrounding him. They were waiting on this wind-swept tarmac at the company’s plant in Palmdale, Calif., to catch a glimpse of the aircraft nicknamed “Lazarus” — the plane that died in a fire on the island of Guam only to be resurrected.

The dot grew larger and larger. Suddenly, the unmistakable bat-winged silhouette of the B-2 stealth bomber emerged. As it touched down for a landing, the crowd erupted in applause, hugs and tears.

“After all that time, it finally made it back home,” Byrne said. “In some ways, we couldn’t believe we pulled it off.”

The four-year operation to rebuild the military’s rarest — and most expensive at $2.1 billion — aircraft involved hundreds of hard-to-find parts, thousands of labor hours, and 300 Air Force and Northrop workers. Many of them, mechanics such as Byrne, left their families in Palmdale and flew 6,000 miles to Guam to work seven days a week for months at a time to restore the stealth bomber.

They spent so much time working on the island, they started calling their temporary home “Guamdale.”

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The military is quick to say that the B-2 is unlike any other aircraft in the U.S. arsenal. Built to haul more than 20 tons of bombs, it has a wingspan nearly as long as a Boeing 747 jumbo jet yet flies virtually undetected by radar.

Because of its stealth characteristics, it is the first bomber to be sent into heavily defended enemy territory to clear the way for other fighters and bombers by knocking out anti-aircraft batteries and radar installations.

On the first night of the NATO operation in Libya in 2011, for instance, three B-2s flew from Whiteman Air Force Base in Missouri, slipped into enemy territory and promptly wiped out 45 targets at an airfield before returning to the U.S.

The bombers are based at Whiteman but are often deployed overseas to Andersen Air Force Base in Guam, a strategic base because of its location in the Asian Pacific region, namely its proximity to China and North Korea.

On Feb. 26, 2010, a B-2 attempted to take off from Guam for a routine training mission when a fireball flashed from a left engine, sparking an onboard blaze that eviscerated the interior of the airplane.

No one aboard was hurt, but the heat was so intense that it melted and warped parts of the B-2’s titanium and aluminum frame. The plane’s wiring and hydraulic tubing turned into smoldering ash.

Though the damage was bad, the Air Force determined that the plane could be saved. That was good news. A B-2 was completely lost in 2008 after moisture built up in the plane’s high-tech sensors and caused it to crash and burn. The pilots safely ejected.

The military said it couldn’t afford to lose another of these aircraft. The repairs required more than 1,000 parts ranging in size from small clips to massive sections that support the structure of the aircraft. The project took nearly four years at a cost of more than $105 million, which included a scheduled overhaul.

“With only 20 B-2s — as precious as those aircraft are — no one even questioned whether or not we’d make the investment,” said Norton Schwartz, a retired four-star general who served as Air Force chief of staff at the time of the incident. “When we found out the aircraft could be saved, civilian and military leadership agreed without hesitation.”

The latest accident was traced to the high-tech material that acts like a sponge to absorb radar waves as they strike the plane. Any gap on the plane’s surface would reflect radar waves. To maintain the plane’s stealth characteristics, radar-absorbing materials are meticulously applied to gaps, including to the areas around the engine exhaust and inside the tailpipe bay.

The 2010 bomber fire started after some of that material broke down, soaked up oil and ignited when one of the B-2’s four engines fired up, according to Air Force investigation documents that were released after a request from the Los Angeles Times.

Once the Air Force decided to rebuild the plane on Guam, getting Northrop’s team on the ground was the first order of business. It summoned the expert mechanics, engineers and other technicians from the company that know the bomber best.

The B-2 bombers were built at Northrop’s 45-acre complex in Palmdale behind razor-wire fences under tight security. The first B-2 rolled off the assembly line in 1988; the last in 1997. Every seven years, the planes fly into the facility for a massive overhaul.

A few weeks after the fire, Byrne’s boss called a meeting around a toolbox in Palmdale to brief the crew on the accident. Byrne, 29, was told he’d be part of the first group going to Guam.

“I was amped to go,” he said. “I had no idea where Guam was. I had to look it up on a map and saw this tiny dot in the middle of the Pacific.”

In May 2010, Byrne and five other mechanics flew to the island to assess the aircraft, which was sitting in a hangar. There appeared to be very little damage to the B-2’s sleek dark-gray surface.

But then the workers popped open the plane’s 100-plus access panels. “The extent of the damage was surprising,” said David G. Mazur, Northrop’s vice president of long-range strike operations. “It took my breath away. Hundreds of parts would have to be replaced.”

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The Air Force has been maligned for decades over the costs and the extensive maintenance the B-2 requires. Last year alone, the Air Force spent more than $1.2 billion upgrading, maintaining and overhauling the fleet.

For each hour a B-2 was in the air, it spent 47 hours on the ground undergoing maintenance. A B-2 mechanic has 750 technical manuals to reference to fix the plane.

On Guam, Northrop determined it would do the repair in two phases. First, the crew would perform the mechanical repairs – estimated at $67.9 million – that would enable the B-2 to fly to Palmdale. Once there, the aircraft would undergo a complete restoration at a cost of about $37.2 million.

Technicians started the first phase by ripping out the aircraft’s subsystems, wire harnesses, hydraulic lines and damaged structures from the engine bay.

Tom McElhaney, a 28-year-old mechanic from the Palmdale plant, said he was thrilled to be part of the team. But he faced a major problem: He couldn’t take all his tools. The team brought high-precision drill bits from Palmdale, but the volume of drilling work required was higher than they had anticipated.

As a result, the bits he used to bore into the structure kept going dull. “We’d keep running back and forth to Home Depot,” he said.

Rebuilding the bomber depended on parts that were difficult to find; some components were discovered on shelves at air bases in the U.S.

Parts that were no longer made were expensive to remake based on blueprints that were drawn when mechanics such as Byrne and McElhaney were in grade school.

All the parts were flown to the island on a specially chartered Air Force C-17 cargo plane.

For a more than a year, Byrne and McElhaney reinstalled equipment in the aircraft. They’d work for two months straight, living in hotels, and head back to Palmdale for 10 days before returning.

“All the days blended together,” Byrne said. “We joked every day was Monday, the 1st.”

The Northrop team worked and traveled in secret. Their families knew where they were, as did co-workers.

But few others were aware of the restoration mission. In fact, the military did not publicly release an accident report and initially downplayed the severity of the damage to the B-2.

The Air Force acknowledged it could have taken a more “proactive approach” in disclosing the extent of the repairs. But Capt. Karen Mock, an Air Force spokeswoman, said the military didn’t do more because no one sought additional details after the first report of the fire.

After 15 months, Northrop workers were eager to see the B-2 take to the sky once again.

“We were all working hard fixing any little issues that came up during the run and things were progressing very quickly,” McElhaney said. “This was actually my first time participating in engine runs and I remember how exciting it was to learn all the new tasks and processes.”

All that attention to detail paid off. The plane, formally dubbed Spirit of Washington, started right up on the first attempt.

Northrop spent the next three months making adjustments to get the B-2 into flying shape. For the flight to Palmdale, the Air Force established strict controls on weight, altitude and speed to lessen stress on the airframe.

In-flight refueling was used so the B-2 wouldn’t have to take on the weight of 50 tons of fuel. A support aircraft followed the B-2 to monitor the 13-hour flight – and coordinate with air traffic control because the aircraft doesn’t readily pop up on radar screens.

McElhaney was in Guam when the bomber took off. “Seeing it leave the island was emotional. It brought a tear to your eye to see it disappear over the horizon.”

Once the B-2 was in Palmdale, workers stripped off the plane’s paint, panels, nuts and bolts, right down to the frame, before rebuilding it with new parts and equipment.

The aircraft was fully restored in December.

When the B-2 left Palmdale to fly home to Whiteman Air Force Base, Byrne and McElhaney were in Palmdale to take in the moment.

“Every plane has its own nickname,” Byrne said. “We said to one another, ‘If we can do this, it’ll be like the story of Lazarus.’”