O peration Rolling Thunder. Its very name evoked, no doubt intentionally, waves of U.S. carpet-bombers obliterating the cities of World War II Germany and Japan. But the Air Force tactical air campaign against North Vietnam, beginning in March 1965, required pinpoint accuracy against infrastructure: “Communist concrete and steel,” said President Lyndon Johnson, “not human lives.” As part of it, on April 3 over 80 American jet fighters, bombers, tankers and camera planes attacked one bridge, 80 miles south of Hanoi, carrying enemy troops, supplies, trains and vehicles over the Ma River, at the village of Thanh Hoa.

Thanh Hoa Bridge

Eight-victory Korean War ace Lt. Col. Robinson Risner, commanding Republic F-105D Thunderchiefs of the 67th Tactical Fighter Squadron out of Korat, Thailand, planned to apply almost 100 tons of high explosive to the bridge. Thirty F-105s each carried eight 750-pound M117 bombs, the largest then available in theater, and 16 carried secret weapons: a pair of the new AGM-12 Bullpup air-to-ground guided missiles. The Bullpup packed only a 250-pound charge but could apply it precisely on target, even when fired from 12,000 feet. On schedule at 2 p.m. local time on April 3, Risner led the first four “Thuds” down and launched his No. 1 missile.

The Bullpup was a guided weapon, but not a self-guided weapon. “The worst part about [the AGM-12] is you got to stay with it,” said Lieutenant (later Admiral) Leighton “Snuffy” Smith, of attack squadron VA-22 from the carrier USS Coral Sea , who recalled firing his Bullpup at a bridge on his first mission over Vietnam. “In other words, you shoot the missile, and then you guide it.”

Because the pilot had to steer each missile, he could fire only one round at a time. Returning to fire again gave enemy anti-aircraft artillery (AAA) another shot. Smith said, “Rule No. 1 is, you never go back for a second time around.”

Risner had learned that the hard way on March 22nd, when he circled back to check on a gun emplacement he thought he had knocked out and his plane was hit, forcing him to ditch it in the Gulf of Tonkin. (“You never get good enough,” he told Time magazine. “A complacent pilot gets killed.”) On April 3, as Risner pulled out of his second run over Thanh Hoa, his Thunderchief took a hit. His plane leaking fuel, the cockpit full of smoke, unable to reach Korat, Risner managed to nurse the crippled Thud south across the Demilitarized Zone to Da Nang. Two other pilots weren’t so lucky. A North American F-100D Super Sabre flown by 1st Lt. George C. Smith was lost to anti-aircraft fire, and he went missing in action. Captain Herschel S. Morgan’s McDonnell RF-101 Voodoo also was hit but made it 75 miles southwest of Thanh Hoa before going down. Morgan would spend the rest of the war as a prisoner.

It was all for nothing. Many of the free-fall bombs had missed the bridge altogether. Risner’s third in command, Captain Bill Meyerholt, confirmed that his own Bullpup made a direct hit but with no result. Sheer brute force—250 pounds of explosive, 750 pounds of explosive, 100 tons of explosive—wasn’t enough to drop the Thanh Hoa Bridge.

Thanh Hoa Bridge, pre-1945

In 1945 Viet Minh Communist rebels blew up the original bridge over the Ma, built by the French colonial government, by ramming two explosive-packed locomotives head-on, midspan. Its replacement, built by the Chinese after Vietnam’s independence and dedicated in 1964 by no less than North Vietnamese President Ho Chi Minh, held tactical importance as military crossing but had psychological importance as well. The steel span, 540 feet long and 56 feet wide, was supported by a central concrete pier 16 feet thick. It had a 12-foot center strip for the 1-meter-gauge Rail Line No. 4 and 22-foot roadways on each side of the tracks for Highway 1A. Hills at both ends, Mount Dragon and Jade Mountain, not only provided the span with solid-rock anchors but also channeled attacking planes into predictable paths. Locals called the bridge Ham Rong, the Dragon’s Jaw. American pilots would learn that it was full of teeth and fire.

At 11 a.m. on April 4 the F-105s were headed back to Thanh Hoa—48 of them with eight M117 bombs apiece. (They left the ineffective Bullpups at home.) Low clouds and haze dictated bomb runs on a heading of 300 degrees, east to west, which meant egress over hostile ground rather than the sea. This time Risner stayed high to observe the enemy’s response. His No. 3, Captain Carlyle Harris, led the way down and released his war load at approximately 4,000 feet, but before he could pull out, the fast-diving Thud was at 1,000, an easy target. Unknown to the Americans, the North Vietnamese had brought heavy 57mm guns to Thanh Hoa during the night. Harris’ F-105 was hit in the tail and last seen trailing flame as it disappeared into the low clouds. Harris survived but would be held prisoner for eight years.

Big guns weren’t the enemy’s only surprise. As the four bomb-laden Thuds in Major Frank E. Bennett’s flight orbited the strike zone waiting their turn to attack, four MiG-17 “Frescos” burst from the clouds onto their tails.

Commander (later Lt. General) Tran Hanh of the 1st Company, 921st Fighter Regiment, Vietnam People’s Air Force, told the Vietnam Courier in April 1965, “I immediately gave orders to attack the first F-105 which I believed was the leader.” He cut loose on Captain James A. Magnusson’s Thud, part of Bennett’s flight, with cannon fire from just 1,500 feet. “The U.S. plane reeled and nosed downward into the fog,” Tran explained. “When I zoomed [by] I clearly saw the white cap of the pilot in the cockpit before the plane crashed headlong on the ground.”

Leading the second pair of MiGs, Le Minh Huan closed to within a few hundred feet of Bennett’s plane before firing. “Hardly had a few seconds elapsed when a flare was seen at its tail,” Tran reported. “Ten seconds after, the U.S. plane belched out a red flame followed with smoke and dived into the fog.”

Bennett fought his flaming Thud around, headed out to sea and ditched, but drowned. F-100 Super Sabres of the 416th Tactical Fighter Squadron sent two Sidewinder missiles and a stream of 20mm shells after the fleeing MiGs. Tran declared that Le and two wingmen were lost in a valiant dogfight, but the Americans claimed no kills and the MiGs likely fell to their own flak around Thanh Hoa.

Of 27 bridges targeted in Rolling Thunder, 26 were down by mid-May. But thanks to its overbuilt construction and round-the-clock repairs—and despite 300 more bombs dropped on it and holes blown through it, pulverized approaches around it and sagging beams beneath it—the Dragon’s Jaw was still operational.

Jaws of the Dragon by Stan Stokes
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This came as no surprise to Brig. Gen. (later four-star general) John W. Vogt Jr., deputy for plans and operations, Pacific Air Forces, who helped plan Rolling Thunder. He knew any bomb off-target by mere inches would explode in the bridge’s upper works—mostly empty air—or deep in the Song Ma. “On the basis of free-fall bombing, with combat CEPs [circular error probabilities; probable impact radii] of 250 to 350 feet, we would never be able to bomb and keep out those bridges,” he said. “You had to have precision and accuracy, and to guarantee that they would be destroyed by normal free-fall bombing would have required far more sorties than were available in all of the air forces of Southeast Asia, if they did nothing else. Also, the enemy had a capability to rebuild those bridges quickly.”

The Air Force planned to employ 3,000-pound M118 demolition bombs and an enlarged “Big Bullpup” with a 1,000-pound warhead to take out the Thanh Hoa Bridge. But those plans were interrupted in November with the formation of a Route Package system for the air war. This set up a half-dozen bombing zones in North Vietnam, divided between the Air Force and Navy. The Dragon’s Jaw, in Route Pack 4, became the Navy’s problem.

Over the summer of 1965, 19 pilots went down on missions around Thanh Hoa. On September 9 Commander (later Vice Adm.) James Stockdale, a future vice presidential candidate, flew a Douglas A-4E Skyhawk against the bridge. Finding that target socked in by rain clouds, he decided to attack a railway siding about five miles west of Highway 1. Stockdale was shot down, and the next evening he got a unique view of the bridge when he was trucked across it as a captive. “It was the Dragon’s Jaw for sure, the one I had left the Oriskany the day before to knock down,” Stockdale said. “There were signalmen, and all passage was single-file due to cumulative bombing damage. I could look up in the reflected light and see that the girders had been twisted and bent by impacts, probably 500-pounders.”

Just a week later, as part of the joint Navy-Air Force “Iron Hand” campaign to attack surface-to-air missiles, Risner learned firsthand how thick the anti-aircraft artillery had become around Thanh Hoa. Hit 10 miles northeast of the bridge, he ejected into the midst of battle. “I had never heard such a thunder of gunfire in my life,” he said. “It was a constant, awesome roar.” Risner would spend seven years as a POW.

By May 1966 Carrier Task Force 77—operating from Yankee Station, an area in the Gulf of Tonkin used as a staging area for Navy airstrikes in North Vietnam—had targeted the Thanh Hoa Bridge two dozen times, using 65 aircraft and almost 130 tons of bombs. Attack squadron VA-146 Commander (later Vice Adm.) Robert F. Dunn remembered the Dragon’s Jaw as “a big trestle bridge that stood out from everything else so well that we felt we just had to get it. After a while it became a symbol, to both the Vietnamese and us. The approaches to the bridge looked like the craters of the moon, and there was an inordinate amount of AAA [anti-aircraft artillery] in the vicinity.”

If the American bombers ever did succeed in blowing up the Dragon’s Jaw, according to local lore recalled by Snuffy Smith, the lieutenant with the VA-22 squadron, “the earth would open up and fall apart, because this was the latch that held it together.”

Finally, the Air Force Armament Development and Test Center at Eglin Air Force Base in Florida offered a key: Project 1559, a 4,000-pound “mass focus” mine, which resembled a hockey puck 8 feet across and almost 3 feet thick—so big it required a transport plane to deploy it. The bomb, dropped upstream, was intended to float down the Song Ma until set off under the bridge by a magnetic fuze. The shaped charge was designed to focus the explosion straight up. Based on the tests at Eglin, there would be a 1-kiloton blast effect 20 to 30 feet above the point of detonation. In May 1966, 10 of those mines, loaded onto two C-130E Hercules transports, were sent to Vietnam under the code name “Carolina Moon.”

Low-level parachute extraction of supply pallet from a U.S. Air Force Lockheed C-130 Hercules. The 4,000-pound Project 1559 mass-focus mine was to be dropped in the same manner.

Major Richard T. Remers took off from Da Nang at 12:25 a.m. on May 30, flying his Hercules up the coast at just 100 feet above the ocean to avoid detection. As he turned inland for the 17-minute run over hostile territory, a Douglas EB-66 Destroyer, an electronic warfare aircraft, jammed enemy radars, and four McDonnell F-4C Phantoms conducted a diversionary attack 15 miles south of the bridge. At the drop point 7,000 feet upriver, Remers slowed to 150 mph and popped up to 400 feet. His crew slid five mines off the rear ramp, each slowed by a pair of 64-foot parachutes, and then the Hercules ran for Tonkin at treetop level.

Dawn reconnaissance runs, however, revealed no trace of the mines or any damage to the bridge. Believing the river level was low and the bombs had run aground short of the target, mission planners decided to try again the following night. Major Thomas F. Case flew the backup Hercules, assisted by navigator 1st Lt. William “Rocky” Edmondson, a veteran of the first attack. They took off at 1:10 a.m. and were never seen again. The crew from one accompanying Phantom reported seeing heavy anti-aircraft fire near the bridge, followed by a bright flash. Another F-4 on the mission was shot down. Come daylight, reconnaissance and rescue planes found no bridge damage, no Hercules and no Phantom. Presumably, one plane sank in the river and the other in the Gulf. Project Carolina Moon, which cost $600,000, was quietly shelved.

The Naval Ordnance Test Center at China Lake, California, where the heat-seeking AIM-9 Sidewinder air-to-air missile was invented, came up with another technology to destroy point targets: a TV camera in the nose of the AGM-62 Walleye glide bomb, enabling the weapon to “see” and lock on to a spot designated from a cockpit screen. The glide bomb could be released from up to 16 miles away. On March 12, 1967, A-4E Skyhawks of VA-21 from USS Bon Homme Richard dropped three 1,100-pound Walleyes over Thanh Hoa. All three struck within 5 feet of the designated aim point, yet they failed to drop the Dragon’s Jaw.

Thanh Hoa Bridge under attack

By November 1968 almost 700 sorties had been flown against the bridge, to no avail. That month Rolling Thunder was discontinued to encourage the North Vietnamese to negotiate. They instead used the lull to rebuild their infrastructure, including the Dragon’s Jaw, strengthening it with additional concrete piers.

The American military-industrial complex, meanwhile, continued working just as hard to devise ways to blow it up. The Armament Development lab at Eglin and Texas Instruments Inc. were exploring military uses for laser beams. In April 1965, the same month attacks began on the Thanh Hoa, they had tested a technology called PAVE, “precision avionics vectoring equipment,” on an M117 bomb: a set of canard steering fins, flick-out rear stabilizer wings, and a laser-seeker module in the nose. During a U.S. airstrike, a plane operating at a safe distance would use a laser to “paint” an impact point on a target. A “Paveway” bomb could then home on the reflected light. Along with a TV-guided version, Paveway 2, PAVE was a relatively cheap guidance system that could turn any existing free-fall munition into a self-guiding smart bomb. But with the bombing restrictions imposed after Rolling Thunder, Paveway was a system with few targets.

On March 30, 1972, the North Vietnamese Army launched what came to be known as the Easter Offensive, an attack on the northern and central sections of South Vietnam with 200,000 to 300,000 troops. At noon about 30,000 NVA soldiers poured across the Demilitarized Zone backed by heavy armor and artillery, much of which had crossed over the Thanh Hoa Bridge. In response, U.S. forces instituted a new full-scale bombing campaign, Operation Linebacker, against the North. By then, the United States retained only half the aircraft it had in Vietnam in 1968, but they were much improved, the Air Force’s F-100 and F-105 having been largely superseded by the F-4, and the Navy’s A-4 by the Grumman A-6 Intruder and Ling-Temco-Vought A-7 Corsair II.

An F-4D from the 435th Tactical Fighter Squadron, 8th Tactical Fighter Wing, armed with two GBU-10s. (U.S. Air Force photo)

On April 27, seven years after the Dragon’s Jaw was first bombed, bad weather over Thanh Hoa blocked laser use, but Phantoms of the 8th Tactical Fighter Wing from Ubon, Thailand, hit the bridge with five 2,000-pound TV-guided Paveway 2 bombs. Though still standing, the bridge could bear no more than foot traffic. The Phantoms returned on May 10 with 48 500-pound conventional bombs, plus 15 2,000-pound and nine 3,000-pound laser-guided Paveways. These didn’t just strike the bridge, they struck the same point on the bridge. When the smoke cleared, its western end had been blown completely off its abutment.

Through the summer of 1972 the North Vietnamese worked frantically to maintain their lifeline to the South, while the U.S. kept bringing down the hammer. After six years Snuffy Smith returned as a lieutenant commander with VA-82 aboard USS America , to find that the Dragon’s Jaw still had not been taken out. “One of the ends of the bridges had been knocked down, and it was literally settled out; but the bridge was still up,” Smith said. “I mean, you take a picture of it, and there’s a bridge there; and the intel guys said, ‘They’re still using the bridge.’ So we continued to try and knock it down.”

His first attempt, with A-7s and Walleyes on October 4, didn’t go as planned. “When we rolled in,” Smith recalled, “my weapon came off but it got hit by a 30mm shell. It disintegrated as soon as it left my airplane, or at least became stupid.”

Two days later Smith and his wingman, Lt. j.g. Marv Baldwin, each packed a pair of 2,000-pound “Fat Albert” Walleye IIs, developed especially for tough targets like the Dragon’s Jaw. “We rolled in simultaneously,” recalled Smith. “Pulled the power back, popped the speed brakes, and we got our scopes locked on to the bridge and I said, ‘lock-on. ‘Once everyone confirmed that they had locked-on, I counted ‘three, two, one, launch,’ and Marv and I both pickled them at the same time.”

Squadron commanding officer Don Sumner and Lt. j.g. Jim Brewster followed up, each with a pair of one-ton Mark 84 general-purpose bombs. “They hit the bridge on the west side of the center piling, and that’s where it broke in half,” Smith said. “In fact there was so much smoke and crap around there, we didn’t know whether we’d hit it and done any damage or not. Later that afternoon, a [North American] RA-5 Vigilante came through and took a picture, and when we looked at them, we finally knew that the bridge was down for good.”

Even with its eastern span lying in the river, nobody seemed able to believe that the Dragon’s Jaw had finally been broken. “I got assigned to Thanh Hoa Bridge about three days later, because it happened to show up on the target list,” Smith remembered. “I said, ‘What in the living hell are you guys doing? I mean, how many airplanes do you want to lose? This thing is in the water. Look at this picture. Read my lips: We don’t want to go back.’ And they said, ‘Well, that’s because it’s on the target list; and they may be trying to build it back.’ I said, ‘Come on, you know, they’re going to take years to build this thing back.’”

The United States was effectively out of the war when the Thanh Hoa Bridge reopened in 1973. In early 1975 much of the North’s invasion force flowed over it on the way to finally conquering the South. Today the bridge, still a vital link between north and south Vietnam, is the site of a national historical park.

Contrary to legend, the world hadn’t come apart with the breaking of the Dragon’s Jaw, but the nature of air combat changed forever. 104 American pilots had been shot down within 75 square miles of the Thanh Hoa Bridge before a handful of smart bombs put it out of business. An Air Force historian called Operation Linebacker “the first modern aerial campaign in which precision guided munitions changed the way in which air power was used.”

Superseded by the AGM-65 Maverick missile, the Walleye glide bomb was retired along with the Corsair II shortly after Operation Desert Storm in 1991, but the Paveway system soldiers on with more than a dozen Western militaries. Those American pilots taking out buildings and bridges around Baghdad and plinking individual Iraqi tanks with 500-pound bombs owed something to their fathers, who led the way in the skies over Thanh Hoa.

The flag still flies. Thanh Hoa Bridge today.

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