Glance down from the ageless expanse of blue sky into the cockpit of the US air force’s largest bomber, and the panorama is decidedly more dated – banks of steam gauges quiver above aluminum levers built during the Eisenhower administration, obsolete knobs and dials unused in decades gather dust.

And much of the rest of the mammoth B-52 bomber is just as antiquated. Vacuum tubes have been replaced with microchips, and the once-standard ashtrays are gone. But eight engines along the wings still connect to the cockpit by yards of cables and pulleys, and the navigator often charts a course with a slide rule.

“It’s like stepping back in time,” said Capt Lance Adsit (28), the pilot. He banked left to start a mock bombing run, wrestling a control yoke forged decades before he was born. Time had stripped it entirely of paint. “I love the B-52,” Adsit said. “But the fact that this is still flying is really insane.”

A few minutes later, his onboard navigation computers crashed. The B-52 is an air force plane that refuses to die. Originally slated for retirement generations ago, it continues to be deployed in conflict after conflict. It dropped the first hydrogen bomb in the Bikini Islands in 1956, and it laser-guided bombs in Afghanistan in 2006. It has outlived its replacement. And its replacement's replacement. And its replacement's replacement's replacement.

Air force commanders are now urging the Pentagon to deploy B-52s in Syria. "We're ready, we're hungry, we're eager to be in the fight," said Col Kristin Goodwin, who commands the Second Bomb Wing at Barksdale Air Force Base in Louisiana, where about half of the bombers are based.

Now in its 60th year of active service, the bomber is slow, primitive and weighed down by an infamy lingering from the carpet bombing of Vietnam in the 1960s. But 76 B-52s still make up the bulk of the United States's long-range bomber fleet, and they are not retiring any time soon. The next potential replacement – the Long Range Strike Bomber, which has yet to be designed – is decades away, so the B-52 is expected to keep flying until at least 2040. By then, taking one into combat will be the equivalent of flying a first World War biplane during the invasion of Iraq in 2003.

Rugged design

The unexpectedly long career is due in part to a rugged design that has allowed the B-52 to go nearly anywhere and drop nearly anything the Pentagon desires, including both atomic bombs and leaflets. But it is also due to the decidedly underwhelming jets put forth to take its place. The $283 million B-1B Lancer first rolled off the assembly line in 1988 with a state-of-the-art radar-jamming system that jammed its own radar. The $2 billion B-2 Spirit, introduced a decade later, had stealth technology so delicate that it could not go into the rain.

"There have been a series of attempts to build a better intercontinental bomber, and they have consistently failed," said Owen Coté, a professor of security studies at the Massachusetts Institute of Technology. "Turns out whenever we try to improve on the B-52, we run into problems, so we still have the B-52."

Officially, the B-52 is called the Stratofortress, but flight crews long ago nicknamed it the BUFF – a colourful acronym that the air force euphemistically paraphrases as Big Ugly Fat Fellow. Too outmoded to be a stealth bomber, the B-52 has become the anti-stealth bomber – a loud, obvious and menacing albatross. It has pummelled armoured divisions in Iraq and has laid thunderous walls of destruction over Taliban positions in Afghanistan.

"The big plane was very good," said one beaming Northern Alliance commander in 2001. In more recent years, it has flown only what the air force calls "assurance and deterrence" missions near North Korea and Russia. In 2013, when China claimed disputed airspace over the South China Sea, a pair of B-52s soared through in defiance.

“The BUFF is like the rook in a chess game,” said Maj Mark Burley, the co-pilot for the training mission over the Great Plains. “Just by how you position it on the board, it changes the posture of your adversary.”

Under question

But the usefulness of the large bomber –and bombers in general – has come under question in the modern era of insurgent wars and stateless armies. Even after millions of tons of bombs were dropped in far corners of the world, most foes targeted by the bomber, including those in Iraq, Afghanistan and Vietnam, ultimately prevailed.

When the first of the top-secret jets rolled off the assembly line in 1954, the air force’s chief of staff proudly called it “the thing that’s going to keep that Red fellow in his place”. Throughout the 1950s, widespread fear of a “bomber gap” with the Soviet Union prompted the air force to churn out more than 740 of the swept-wing bombers at a then-unprecedented cost of about $8 million each. The last was built in 1962. Even as the bombers were being assembled, defence officials were planning their replacement, but each plan was undone by its own complexity. First was a nuclear-powered bomber able to stay aloft for weeks (too radioactive), then the supersonic B-58 with dartlike wings (kept crashing), and then the even faster B-70 (spewed highly toxic exhaust).

“This was high-tech, futuristic stuff, but because it was so futuristic, the projects ran into problems,” said Yancy Mailes, an Air Force historian. A front-page story in the New York Times in 1966 said all B-52s would need to retire by 1975 because they would “be too old to continue beyond that point.” But no viable alternative emerged.

In 1982, President Ronald Reagan warned, "Many of our B-52 bombers are now older than the pilots who fly them". Today, there is a B-52 pilot whose father and grandfather flew the plane. Reagan rushed production of the B-1, which was designed to fly fast and low beneath enemy defenses. It was expected to replace the B-52 in the 1990s, but in a prelude of future problems, the first B-1 unveiled in 1985, in front of a crowd of 30,000, failed to start. Design flaws and engine fires sidelined the plane during the Persian Gulf war and have limited its capabilities since.

Next came the B-2 stealth bomber in 1997. But the B-2, with its delicate radar-evading coating, had to be stored in a climate-controlled hangar to be effective, and its sensors at first could not tell a storm cloud from a mountain. It soon became known as the $2 billion bomber that cannot go out in the rain.

The B-52 became a technologically humble – but still frighteningly effective – stand-in.

Nuclear retaliator

Although the fleet was designed as a nuclear retaliator, it began bombing the countryside of South Vietnam in 1965. Rebutting claims that B-52s were missing most of their targets, one pilot said at the time, “We’re doing a lot more than killing monkeys and making kindling wood out of the jungle.” A New York Times correspondent interviewing him marvelled that the bombers were almost a decade old, “yet the mechanics keep them flying.”

In 1972, during the so-called Christmas bombing, wave after wave of B-52s destroyed sections of Hanoi in North Vietnam, killing hundreds of civilians and prompting nationwide protests and international condemnation. But the bombers were far from done. In the Persian Gulf war, Kosovo, Afghanistan and the Iraq war, the lumbering jets, well-established as a symbol of death and destruction, demoralised enemy ground troops by first dropping tons of leaflets with messages like "flee and live, or stay and die," then returning the next day with tons of explosives.

The US air force is trying to change the image of the B-52 from indiscriminate carpet bomber to precision weapon. Laser-targeting pods attached to the wing of many of the bombers in recent years allow them to drop guided “smart” bombs. In recent years, the big bombers circling high above Afghanistan acted as close air support. “We’re as accurate as a fighter,” said Lt Col. Sarah Hall, a B-52 pilot who flew missions over Afghanistan. “And sometimes just the sight of the B-52 is enough to end the fight. The enemy just takes off.”

While its weaponry has been upgraded, the rest of the plane can look like a midcentury museum exhibit. Ground crews scouring the ageing frames for rust often find graffiti in hidden nooks by previous generations – a recent discovery, perhaps commenting on the age of the planes, featured primitive cave-style animal paintings. However, despite intensive maintenance, the planes’ ages are starting to show. On a recent training flight out of Barksdale Air Force Base after three days of rain, leaks in a bomber left the seats soaked and the control panel glistening. One engine refused to start, then some wiring shorted.

“This is really the full BUFF experience,” the co-pilot said with a patient grin as the maintenance crew scrambled to fix problems. “But once we get airborne, we’re usually okay.”

Bomb runs

A few minutes later, the bomber with a crew of five roared into the sky and banked toward its mock bombing target in Texas. In a dark den beneath the pilots, two weapons officers charted their position and calculated bomb runs. Among their tools: rulers and stopwatches. Halfway through the mission, their aging navigation system crashed. Then it crashed again.

Lt Nicole White (31), a weapons officer with her hair in an unruly bun and an energy drink sitting next to her slide rule, called the pilot on the radio. “We have a computer that is potentially catawampus,” White said. “What does catawampus mean?” said Adsit, the pilot, with a laugh. “Cray-cray,” she responded. For several minutes as the computer rebooted, the bomber flew, relying on its original 1950s technology of charted maps and line of site.

Impressions of the bomber have proved almost as lasting as the jets themselves. At the entrance to Barksdale, a retired B-52 from Vietnam sits on display. On a sunny fall morning, a former officer from the South Vietnamese navy named Phuoc Luong stood taking photos of his wife in front of the hulking plane, which had dropped tons of bombs on his country – bombs that still explode unexpectedly in farm fields, killing and maiming people 40 years after the war ended.

Now 69 and retired, living in Massachusetts after fleeing his homeland in 1975, Luong said he was not surprised to see B-52s still flying. “American technology is super,” he said. “It’s a great plane. In Vietnam, we didn’t use it enough. That’s why we lost.”

New York Times service