Major Merlyn Dethlefsen and the Medal of Honor Wild Weasel Mission of Lincoln 03

Major Merlyn H. Dethlefsen

By March 1967, Operation Rolling Thunder had been going on for two years with no signs of North Vietnam backing down. The United States and North Vietnam engaged in a gradual escalation of the conflict. As US air strikes increased, the Hanoi regime increased its anti-air defenses from AAA to the more deadly SA-2 surface-to-air missiles as well as MiG fighters. The skies over North Vietnam would be the most dangerous and difficult skies for American pilots to operate in since World War 2. At the start of Rolling Thunder, defense suppression was assigned to two-seat F-100F Super Sabres known as the Wild Weasels. The F-100 was in interim solution for the Wild Weasel role, though, as it had a limited payload and wasn't fast enough to keep up with the F-105 Thunderchiefs that were shouldering the burden of strike missions at the time for the USAF. In June 1966 the first Thunderchief Wild Weasels arrived in Southeast Asia. One of the Wild Weasel units at the time was the 354th Tactical Fighter Squadron at Royal Thai Air Force Base (RTAFB) Takhli which was home to the F-105s of the 355th Tactical Fighter Wing. The 355th TFW had been operating the Thunderchief since 1962 at McConnell AFB in Kansas before being deployed for Rolling Thunder. Like the F-100Fs, the Wild Weasel F-105Fs had two crew, the pilot and the electronic warfare officer in the back, the EWO or "Bear". 

Dethlefsen and Gilroy in their Wild Weasel F-105F

On 10 March 1967, the target portfolio was finally expanded to include the large Thai Nguyen steel works. The area was the center of North Vietnam's heavy industry and the only steel mill (it actually was the first steel mill in Indochina, having started production in 1959) and for most of the first two years of Operation Rolling Thunder, it remained off the target list for political reasons. A large Thunderchief strike package made up of single-seat F-105Ds and Wild Weasel F-105Fs for defense suppression was sortied against the steelworks by the 355th TFW from RTAFB Takhli. One flight of four Wild Weasels with the call sign "Lincoln" was part of this strike package on this day. As the flight approached Thai Nguyen, Lincoln Lead's Bear locked up a SAM site and an AGM-45 Shrike missile was fired, but it missed. The SAM site, however, did not, and in short order Lincoln Lead along with two F-4 Phantoms flying escort were shot down. Lincoln 02 took flak damage and had to withdraw and limp back to Takhli. That left only two Wild Weasels in the area, Lincoln 03 piloted by Major Merlyn Dethlefsen and his Bear, Captain Kevin Gilroy, and their wingman, Major Ken Bell in Lincoln 04. As Dethlefsen and Gilroy targeted the SAM site, two VNAF MiG-21s entered the fight, closing in on Dethlefsen from behind. Lincoln 03 fired their Shrike missile and immediately hauled the heavily laden F-105F into a hard turn, causing the missiles from the attacking MiG-21s to go wide and miss. Gambling that the MiGs wouldn't follow him into the flak zone that protected the SAM site, Dethlefsen pressed on instead of jettisoning his bombs as was the practice when jumped by MiGs- for the VNAF, getting a Thunderchief to jettison its bombload was as good as shooting it down since it wouldn't be able to press its attack. Sure enough, the MiGs didn't follow him to the deck and at low altitude, Dethlefsen hit the afterburner to regain altitude. Just as he had reached position to hit the SAM site, another pair of MiGs closed in and opened fire on Lincoln 03 and Lincoln 04. Both took 37mm cannon hits but were still flying. 

With the last of the strike F-105Ds and their Phantom escorts egressing the area, Dethlefsen knew the weather forecast was good for the next several days and that the Thai Nguyen steel plant was long on the wish list for the pilots to hit. Though he would have been in his right by USAF procedure to follow the rest of the aircraft and leave the area for Takhli, Dethlefsen elected to take another crack at the SAM site as he knew more of his fellow pilots would be returning over the next several days. Leading his wingman, Dethlefsen scanned the flak pattern from a safe altitude while Kevin Gilroy acting as his Bear got a bead on the SAM site with the Wild Weasel's electronics. Once Gilroy pinpointed the site, they fired their Shrike missile to knock out the guidance radar. Dethlefsen then led his wingman down into the flak zone to put the SAM site out of business. Getting a visual on the site, Dethlefsen unleashed his bomb load across the site and then pulled out. For added insurance, he rolled his damaged Thud into a reverse flip, switched to guns and hosed the site down with his 20mm Vulcan cannon. He then nursed his F-105F out of the target zone and hooked up with a KC-135A tanker on the way back to Takhli. 

Merlyn Dethlefsen and his EWO, Kevin Gilroy

It was a Medal of Honor performance, but what did Dethlefsen do that was so brave? First of all, by USAF procedure he was to have exited the area as the strike package left- one of the mottos of the Wild Weasels was "First in, last out". Instead, he decided to take another crack at a SAM site. Dethlefsen wasn't naive. On the day of this mission he already had 72 Wild Weasel combat missions under his belt. He knew if the site wasn't knocked out, it would more than likely shoot down more crews in the coming days. And this wasn't just any target- this was a prized asset of the North Vietnamese and it was heavily defended. More American aircraft were shot down in 1967 than any other year of the Vietnam War. The skies over Thai Nguyen were not a good place to be for an American pilot that day, month, and year. Add to that the Wild Weasel mission profile that exposed their crews to hostile fire longer than most pilots. 

Merlyn Dethlefsen was born in 1934 on a farm in Iowa and he joined the USAF in 1954 through the Aviation Cadet Program. From 1957 to 1959 he served as a navigator on the Douglas C-124 Globemaster II out of Dover AFB before reporting to undergraduate flight training. His first operational assignment after getting his wings was flying F-100 Super Sabres in Germany before transitioning to the F-105 Thunderchief in 1965. After his Medal of Honor mission (his Bear, Kevin Gilroy, earned the Air Force Cross for that mission), he went on to complete his 100 mission tour in Vietnam. He would later go on to serve as an operations director for the SR-71 wing at Beale AFB in California and for the B-52 wing at Dyess AFB in Texas. Dethlefsen flew west in 1987 and was laid to rest at Arlington National Cemetery. 

Source: Above and Beyond: The Aviation Medals of Honor by Barrett Tillman. Smithsonian Institution Press, 2002, pp 225-227. F-105 Thunderchief Units of the Vietnam War by Peter Davies. Osprey Publishing, 2012. Photos: USAF Museum, Wikipedia.

Operation Kingpin: The Son Tay Prison Raid

Operation Kingpin, the raid on the Son Tay prison in North Vietnam, was the largest and most complex special operations mission of the Vietnam War. It would be a joint operation with the Army, Navy, and Air Force with 59 men led by the legendary Col. Arthur "Bull" Simons in the actual ground team that would enter Son Tay. One-hundred sixteen aircraft from the USAF and the US Navy participated, with the Navy aircraft flying from three aircraft carriers to conduct diversionary operations to allow the Son Tay raiders to sneak into North Vietnam from Laos.

On the night of 20 November 1970, the Kingpin force had departed RTAFB Takhli in Thailand just north of Bangkok. After a rendezvous over Laos for aerial refueling, the raiding force itself consisted of the following elements:

• Cherry 1: Lockheed C-130E (Raid force mission leader)
• Cherry 2: Lockheed C-130E (Mission leader for the Douglas A-1 Skyraiders flying close air support as Peach flight)
• Banana 1: Sikorsky HH-3E Jolly Green Giant (Assault team, they would intentionally crash land in Son Tay's courtyard)
• Apple 1, 2, and 3: Sikorsky HH-53 Super Jolly (Assault team)
• Apple 4 and 5: Sikorsky HH-53 Super Jolly (POW transport)
• Peach 1-5: Douglas A-1 Skyraider (Close air support)
• Falcon 1-10: McDonnell Douglas F-4 Phantom II (MiGCAP)
• Firebird 1-5: Republic F-105G Thunderchief (Wild Weasel SAM suppression)

In addition to the raiding force, a multitude of other tankers, early warning aircraft and Navy combat aircraft were assigned vital supporting roles to make Operation Kingpin possible. For at least a year up to the actual raid on Son Tay, the prison complex was a high-priority reconnaissance target imaged by both spy satellites and Lockheed SR-71 Blackbird flights as analysts and planners set about determining the forces defending Son Tay as well as the routines of the personnel and prisoners of the complex. Something as simple as laundry hanging out in the prison courtyard offered valuable clues. In the last few months before the raid took place, reconnaissance had shown that the North Vietnamese had added two SA-2 "Guideline" SAM battalions to the area. Each SAM battalion was self-contained with its own radars, command and control equipment and four SA-2 missile sites, each site with six launchers and 12 missiles. With two of these battalions in the area, that meant eight SAM sites would be defending the prison complex. And these SAM sites were often protected by a large number of mobile antiaircraft guns.

To meet this dangerous threat to the aircraft of the Kingpin raiding force, the 6010th Wild Weasel Squadron flying the SAM-site killing F-105G Thunderchief were added to the raiding force to knock out the missile sites. Firebird 1 through 3 would accompany the raiders all the way to Son Tay and orbit the area, knocking out the SAM sites as their radars went active. Firebird 4 and 5 were to act as spare aircraft in case anything happened to either Firebird 1, 2 or 3 during the mission.

As the assault teams hit the ground, the SAM site radars went active and the first of 18 SA-2 missiles were fired during the raid- but only two of them targeted (and missed) the helicopters, A-1 Skyraiders or the C-130s acting as mission command posts. The rest of those SAMs bored in on the F-105s of Firebird flight. Firebird 3 took a hit but was able to disengage and its crew were able to nurse the damaged aircraft to RTAFB Udorn in Thailand. As Firebird 3 disengaged, Captain Don Kilgus and his back seat electronic warfare officer (EWO, or "Bear"), Captain Clarence Lowery in Firebird 5 were called into action to duel with the SAM sites. One missile managed to detonate close to Firebird 5, but Capt. Kilgus felt their F-105G wasn't damaged seriously and he and his EWO pressed their attack, knocking out the site that had fired the offending missile.

Unbeknown to the raiders, the POWs at Son Tay had been moved the previous August to a new facility 12 miles away called Camp Faith. The POWs there were awakened by the sounds of the SAM launches trying to down the raiding force. Some weren't able to see out their barred windows but the prisoners on the west side of the building could see the flares, the SAM detonations in the sky, and the explosions by Peach flight's close air support strikes. Word spread amongst the POWs "They're raiding Son Tay!"

Disappointed having not found and rescued any POWs at Son Tay, the raiding force withdrew from the area in less than 26 minutes. Not a single man was killed and only two were wounded. The 59 men and their support aircraft had managed to kill 200-300 enemy troops.

As Firebird 5 withdrew with the rest of the F-105Gs from the raiding force, Capt. Kilgus realized their were losing fuel. And they were losing it fast. The near-miss by the SA-2 detonation had showered their aircraft with shrapnel and punctured nearly all the aircraft's fuel tanks. With the fuel loss too great to be offset by tanking from an orbiting KC-135, Kilgus and Lowery were forced to eject over the mountains of Laos. They had managed to eject near each other and met up on the ground and began to radio their location to await rescue. As it turned out, the nearest rescue helicopters to their position were two of the returning HH-53 Super Jollies from Son Tay, Apple 4 and Apple 5. After a midair refueling from C-130 Hercules tankers, the two helicopters diverted and plucked Kilgus and Lowery from the jungle, making them the only two pilots rescued in the Son Tay prison raid.

Dejected by their failure to rescue any POWs, what wasn't immediately apparent to the men of Operation Kingpin was that their historic raid scared the Hanoi government about the strength of the resolve of the United States when it came to the POWs. Within two days POWs that were scattered across camps in North Vietnam in small groups were crowded together at the infamous "Hanoi Hilton" where the lethal air defense umbrella around the capital would prevent any future rescue attempts. Prior to Son Tay, many POWs were in isolated groups and this isolation was used as a psychological weapon by their captors. With all the POWs now in one facility, the "Hanoi Hilton" was simply too crowded for isolation to be used and the morale of the prisoners skyrocketed as they were housed together in large groups, getting moral support from each other. The men from Camp Faith shared their stories of what they had seen that November night in the skies over Son Tay and all former POWs to this day mark their time in captivity by either "before Son Tay" and "after Son Tay".

Source: Beyond Hell and Back: How American's Special Operations Forces Became the World's Greatest Fighting Unit by Dwight Jon Zimmerman and John D. Gresham. St. Martin's Griffin Press, 2007, p21-60.

Four years after its first flight the Republic F-105 Thunderchief in the form of the first production variant, the F-105B, finally reached operational status. Two years prior, though, planning had already begun for the definitive Thunderchief variant, the F-105D, and it was this variant that made up the bulk of the F-105's production run. The USAF's early plans were for 800 F-105s to equip 11 fighter wings of the Tactical Air Command. However, when the US Navy's new McDonnell F-4 Phantom II began smash existing records with its performance, Thunderchief production was abruptly curtailed in favor of the first USAF versions of the Phantom which offered a multirole versatility that the strike-optimized Thunderchief lacked.

Of the 833 Thunderchiefs built, 610 of them were F-105Ds and 143 were the two-seat F-105Fs that would later be converted into the F-105G Wild Weasel aircraft. All were built at Republic's Farmingdale, New York, facility on Long Island.

The Vietnam War, however, decimated the ranks of the F-105s. In the seven years that the F-105 flew combat missions in Vietnam from 1965 right into the 1972 Linebacker II attacks, of the 753 F-105D/F/G models that fought in the war, 395 of them were lost in the war- 296 of those losses were the single seat F-105Ds and the balance of that nearly 400 losses were the F-105F/G models. In addition to those staggering losses in the face of some of the most intense air defenses of the time, an additional 61 F-105s were lost in Southeast Asia from non-combat causes ranging from mechanical failures, engine problems, even mid-air collisions.

When the F-105Ds were withdrawn from combat in 1970, there were only enough Thunderchiefs for three USAF wings- the 347th TFW at Yokota AB in Japan, the 23rd TFW at McConnell AFB, and the 57th FWW at Nellis AFB. In less than two years, those F-105Ds were then passed on to Air National Guard squadrons (yes, squadrons- attrition left only enough Thunderchiefs at this point for single squadrons instead of entire wings) in New Jersey, Kansas, Virigina and the District of Columbia. Three USAF Reserve squadrons briefly operated the F-105D as well, but heavy combat use in Vietnam led to stress and fatigue in the Thunderchief's structure.

The Wild Weasel F-105Gs fared a bit better, having fought on to 1972 before US involvement in Vietnam ended in 1973. Enough of the G model Wild Weasels survived the war to equip three squadrons at George AFB in California where they served as trainers for crews destined for the more advanced McDonnell F-4G Phantom Wild Weasel. The survivors at George AFB ended up with the Georgia ANG.

With few Thunderchiefs left after Vietnam and many having used up their flight hours by the late 1970s, the F-105 had the dubious only of being the only US combat aircraft to be withdrawn from service solely on account of attrition rather than obsolescence.

Source: International Air Power Review, Volume 6, Autumn 2002. "Warplane Classic: The Republic F-105 Thunderchief" by Larry Davis, p120-155.