The Thanh Hóa Bridge (Vietnamese: Cầu Hàm Rồng, Hàm Rồng Bridge), spanning the Song Ma river, is situated northeast of Thanh Hóa (), the capital of Thanh Hóa Province in Vietnam. The Vietnamese gave it the nickname Hàm Rồng (Dragon's Jaw). In 1965 during the Vietnam War, it was the objective of many attacks by US Air Force and US Navy aircraft which would fail to destroy the bridge until 1972, even after hundreds of attacks. The bridge was restored in 1973. As of 2016, the bridge still stands.
Originally built by the French during the colonial era in Vietnam, the Thanh Hóa bridge was sabotaged by the Viet Minh in 1945. From 1957, the Vietnamese started rebuilding it. Allowing the passage of both road and rail traffic, it was a vital link between different regions of North Vietnam, and when the war started, became a strategic passage for supplies and reinforcements sent to the Viet Cong fighting in South Vietnam.
In their first air combat, a small force of seemingly mismatched MiG-17s inflicted significant losses on much larger and more advanced American F-105 Thunderchief at a cost of three of their own, with an F-100 Super Sabre claiming the first probable American kill of the conflict. The encounter led to significant changes in American tactics and training, and a return to dog-fighting in air combat doctrine. Eventually, in 1972, the bridge was destroyed by USAF F-4 Phantoms using laser-guided bombs and US Navy Vought A-7s with advanced and conventional bombs.
The bridge It was a grey metallic construction, resting on a central concrete pier, and on concrete abutments at each extremity. Completed in 1964, and inaugurated by Ho Chi Minh, the final bridge was long, wide, and about above the river.
Operation Rolling Thunder With the beginning of Operation Rolling Thunder (the bombing campaign against random targets in North Vietnam chosen by Lyndon B. Johnson), the decision was made in March 1965 to interdict the North Vietnamese rail system, including the Thanh Hóa bridge. The Vietnamese, realizing the importance of the bridge, had set up an impressive air defense network, stationing five air defense regiments in the area.
First raid, first dogfight
The first — and largest — strike package to be sent against the bridge was codenamed 9-Alpha. Led by Korean War ace Colonel Robinson Risner, it comprised 79 aircraft, including 46 F-105 Thunderchiefs as the main strike force. Other types were 21 F-100 Super Sabres as AAA suppressors to attack ground-based guns, fourteen F-100s acting as MiG CAP (combat air patrol) and two RF-101C Voodoos to do damage assessment, plus ten KC-135 tanker aircraft.
The F-100s were based in South Vietnam, while the others were based across Thailand. Flights of four F-105s from Royal Thai Air Force Base (RTAFB) Korat and RTAFB Takhli would be air refueled over the Mekong River, then cross Laos to just south of the bridge. The bombers would continue east until over the Gulf of Tonkin.
Launched on April 3, 1965, the attack saw all strike aircraft deliver their payload. Sixteen of the F-105s carried a pair of Bullpup missiles, one under each outer wing pylon. This was an early combat use of early "smart" precision guided missiles that were guided by radio and joystick, requiring two passes to launch each of two missiles per plane. Capt. Bill Meyerholt observed as the missile streaked toward the bridge and made a good hit; when smoke cleared, there was no visible damage to the bridge. The warheads merely charred the massive structure.
The other F-105s each carried three tons of explosives in the form of eight bombs, more than B-17s had delivered over targets like Berlin. The first wave of bombs drifted due to a strong southwest wind. The last flight, led by Cpt. Carlyle S. "Smitty" Harris, scored hits on the roadway and superstructure. After 32 Bullpups and 1200 bombs had decorated the bridge with numerous hits, charring every part, the bridge did not fall, though traffic was stopped for a few hours. This was the only result of the raid, which had cost two aircraft — one F-100 (Lt. George C. Smith flying flak suppression) and one RF-101 — shot down.
Risner's Thunderchief was crippled by ground fire but, despite smoke in the cockpit, Risner continued to direct the strike before flying safely back to Da Nang.
To meet the raid, the VPAF (Vietnam People's Air Force) had sent out two flights of four MiG-17PFs from Noi Bai airbase at 09:47. The original plan was for the first flight to act as a decoy. The second flight never reached the strike force, as flight leader Pham Ngoc Lan spotted F-8E Crusaders from the covering the operation. The metal-finished MiG-17PF was an all-weather interceptor version of the MiG-17 first flown in 1951. Armed with three 23mm cannons but no missiles, it was a faster upgraded MiG-15 fitted with an afterburning engine, and a radar-ranging gunsight reverse-engineered from the F-86A (as well as a new, more sharply swept wing to increase its critical Mach number, therefore top speed).
By comparison, the American Crusader was a daylight gunfighter capable of speeds of nearly twice the speed of sound, armed with both cannon and Sidewinder missiles. Lan dived to attack at about 1,000 feet, and fired at a range of 700 feet. His gun camera showed a blazing F-8 which he reported had crashed. At 10:15 wingman Lieutenant Phan Van Tuc fired on another F-8, claiming a second victory. Pilots Ho Van Quy and Tran Minh Phuong also opened fire on two F-8s, but were out of gun range. In the VPAF's evaluation, their success was due to proper preparation, using surprise and engaging only in close dogfights. While the US Navy records that all of the Crusaders returned, a plane flown by Lt. Cdr. Spence Thomas was so damaged it diverted to Da Nang and was written off as destroyed upon landing. That could make Lan's attack the first air-to-air kill not only by the VPAF's MiG-17s, but the first air victory of the conflict.
The Navy recorded that an A-4 Skyhawk of Lt. Cdr. R. A. Vohden was lost to AAA; Vohden spent the rest of the war as a POW. After his victory, Lan found himself short on fuel. He elected to save his plane by making a hard landing by a riverbed in the Ke Tam valley (Nghệ An Province). He was besieged by locals who expected to find an American pilot until he showed his VPAF badge.
The VPAF had nevertheless demonstrated the ability to engage modern US fighters, and afterwards recognized April 3 as Air Force Day. On the American side, the failure to drop any spans led to a new attack scheduled for the next day; it was expected by VPAF commanders. This time, eighty planes were engaged, including 48 F-105s, carrying only bombs, as the inadequacy of the Bullpup had been fully demonstrated.
MiG-17s jump USAF F-105s
During the 4 April 1965 engagement, a force of eight MiG-17s (half flying as decoys) from the 921st "Sao Do" (Red Star) Fighter Regiment (FR) were again given the task of confronting a large group of modern American supersonic fighter-bombers.Anderton p. 71" The 46 F-105 Thunderchiefs tasked as fast attack bombers were escorted by a flight of 21 F-100 Super Sabres daylight fighters from the 416th Tactical Fighter Squadron (416th TFS), four Sidewinder-armed for MiGCAP, and seventeen armed with 2.75-inch HVAR to suppress AAA batteries.
Each flight was given a call sign. These included "Steel", "Iron", "Copper", "Moon", "Carbon", "Zinc", "Argon", "Graphite", "Esso", "Mobil", "Shell", and "Petrol". "Cadillac" flight conducted Bomb Damage Assessment, while the search and rescue included A-1 Skyraiders, call sign "Sandy", and HH-3 Jolly Green Giant rescue helicopters, call sign "Jolly Green."
The VPAF made ground-based AAA sites the first line of defence, with fighters attacking after ground gunners ceased fire. After taking off at about 10:20, the MiGs would break into decoy and attack flights. The leader was second-in-command Nguyen Van Tien, while Dao Ngo Ngu handled the ground control command.
The Americans started with recon flights over Thanh Hóa. Then the attacking jets flew in flights of four. One flight would attack at a time while others circled awaiting their turn. Although, on paper, the F-105 was capable of Mach 2+, when loaded with ordnance under its small wings, it was subsonic and unready to tangle with any fighters that might get past the escorts. Covering the north, in the direction of Hanoi's airfields, escorting F-100s sixty miles north of the Song Chu estuary where the river meets the sea, were to warn of enemy aircraft and if possible to intercept, while four others orbited south of the estuary.
The MiG attack came instead from the south, with part angling off toward the west, perhaps to draw away escorts as a decoy. As the MIGCAP F-100s flew south, they spotted MiG-17s flying in from the sea toward the F-105s, and urgently radioed the warning: "Break off!" But their warnings weren't heeded due to garbled transmission. The strike aircraft flew on like sitting ducks, unaware of the incoming threat. While North Vietnam had full radar coverage and ground control of their pilots, the short-range, forward-scanning radars in the F-100s didn't spot the MiGs in a part of the sky where they were not expected. The USAF would later use EC-121s to provide full 360 degree radar coverage for strike packages.
Coming from clouds above, the MiG-17s tore past the escorts and dove onto the bomb-laden Thunderchiefs. Vietnamese flight leader Trần Hanh spotted four F-105Ds at 10:30 starting to drop their bombs, ordering his wingman, Pham Giay, to cover his attack. He fired at 400 meters, observing one F-105, piloted by Major Frank E. Bennett (355th TFW, KIA) fall in flames into the Gulf of Tonkin. The flight leader attempted to recover at Da Nang but had his controls freeze up within sight of the base. Ejecting, he was killed when his parachute failed to open before he struck the water.How It Happened Time Friday, Apr. 16, 1965
As the F-105s turned to attack the MiGs, the MiGs split into two groups on the north and south sides of the bridge. Supported by Tran Nguyen Nam, Le Minh Huan downed another F-105D, callsign Zinc 2 piloted by Capt. J. A. Magnusson. He radioed that he was heading for the Gulf if he could maintain control of his aircraft. Magnusson finally bailed out twenty miles away over the Gulf of Tonkin near the island of Hon Me, and was eventually listed as missing and then killed after a 48-hour search.bridge attack The USAF confirmed the two F-105 losses during that engagement.
The remaining F-105 found himself in the sights of another MiG-17 whom he could not shake. In desperation, he tried a snap roll which slowed his plane so that the MiG-17 over-shot him, as his captain had recommended. Finding himself on the MiG's tail, he was too surprised to attempt to shoot down the MiG with his gun. The fortunate pilot was briefed the day before about this maneuver by Captain John Boyd from Nellis Air Force Base, who would later become a significant voice in the design of America's fighter aircraft.Tribute To John R. Boyd By Harry Hillaker
After the quick success of downing two American fighters, the outnumbered North Vietnamese defenders faced the remaining F-100s and F-105s now fully alerted to their presence and turning their attention to the MiGs. Tran Hanh ordered his flight to split into two groups. He and wingman Pham Giay stayed south of the bridge, while Le Minh Huan and Tran Nguyen Nam flew to the north. Three F-100s from the MiGCAP, piloted by LTC Emmett L. Hays, CPT Keith B. Connolly,Anderton 1987, p. 71. and CPT Donald W. Kilgus, all from the 416th TFS,Davies pp. 87, 88. engaged the MiG-17s. As the F-100s closed in, they hesitated to fire missiles which might hit their F-105s. The lead F-100 got a locking tone as he fired an IR guided Sidewinder air-to-air missile once he had a clear shot, but it passed above its target, while Connolly and Kilgus engaged with 20mm cannon.