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 Teaball: Network-Centric Real-Time Intelligence During Vietnam

In 1972, US fighters had an added resource in the fight against MiGs

In past blog posts I've discussed some of the measures taken by the military to reverse the decline in air combat proficiency in the skies over Vietnam. This past November I had blogged about the origins of Red Flag as well as the top secret USAF program to obtain and fly MiGs. Back in March I wrote about the US Navy's own efforts that began with the Ault Report. While these were all steps that would benefit fighter pilots in the skies over Vietnam, there was another effort that took place that has received scant attention in the history books and presaged today's military buzzword of "network-centric" warfare. Between the bombing halt of 1968 and the start of the North Vietnamese Easter Offensive in 1972, air combat over North Vietnam was nearly non-existent. With the start of the NVA offensive in 1972, though, President Nixon reversed the gradual drawdown of US forces in Southeast Asia with a massive buildup and bombing offensive under Operation Linebacker I and Linebacker II. With the ramp up of offensive air strikes on North Vietnam, US aircrews found themselves embroiled in multiplane dogfights that were resulting in growing US losses. In the three months following the start of Linebacker in May 1972, the US lost 48 aircraft, 21 to VNAF MiGs and 27 to improved ground defenses. In the same period, only 31 MiGs were shot down by US aircraft and things worsened in the summer with 13 US aircraft lost to MiGs and only 11 MiGs shot down. 

At the same time, the policy of rotation of air crews meant that experienced personnel were rotated out of combat and replaced with novice air crews on their first combat tour. In the days before Red Flag and dissimilar air combat training, the loss rate of first tour air crews was staggering enough the General John Vogt, commander of the Seventh Air Force which oversaw combat air operations in Southeast Asia, ordered the minutes of mission critique conferences to be disseminated to all units in theater, not just the units involved. But it wasn't enough for General Vogt. He reported to the USAF Chief of Staff, General John Ryan, that the US was losing the air war over Vietnam in 1972. As a result, General Ryan ordered his staff to create a plan to assist US pilots in the skies over Vietnam- no studies, no plans, but what General Ryan wanted was something in place that could offset the fact that the VNAF MiG pilots were battle-experienced and had excellent GCI controllers who could relay the MiG air crews detailed descriptions of the tactical situation. 

General John Vogt, commander USAF Seventh Air Force

Ryan tasked a three-man "action group" with setting something up- USAF officers Lt. Col. William Kirk and Maj. Ernie Short teamed up with Delmar Lang, an intelligence specialist with the National Security Agency. Lang was brought in as he had several times in the years prior repeated offered to set up an eavesdropping facility that could listen in on the communications between the VNAF MiG pilots and their GCI controllers to provide real time information to US pilots. Lang's idea had historical precedence- during the Korean War, the USAF had a listening post on the island of Cho-do off the coast of Korea that was staffed with linguists and air control specialists that would listen in on North Korean, Chinese, and Russian communications to give US pilots a real-time picture of what was going on in "MiG Alley". Since the Korean War, the pace of technological progress in electronic and signals intelligence (ELINT and SIGINT) improved by leaps and bounds, but national security and a variety of compartmentalized secret programs kept many of these new methods out of sight to those on the front line. Delmar Lang's NSA position, however, coupled with the access given Lt. Col. Kirk and Maj. Short, intended to cut through the institutional resistance to using those technological resources to win the war in the skies of over Vietnam. 

On 26 July 1972, literally in just one month, General Ryan's "action group" set up the Operation Teaball Weapons Control Center at the Thai air base of Nakhon Phanom (nicknamed "Naked Fanny" by US pilots). Working with the intelligence specialists of the USAF's 6908th Security Squadron, the Teaball control room had map displays where data from a variety of intelligence sources already in place was collected and synthesized to form a single tactical picture that could be disseminated to US pilots in real time by specialist ground controllers. Orbiting high over the Gulf of Tonkin and Laos, specialist ELINT/SIGINT RC-135s listened in on communications between MiG pilots and their GCI controllers- this data was then relayed to a Lockheed U-2 orbiting high overhead that then relayed the information direct to the Teaball control center at Nakhon Phanom. Ground and ship-based (like "Red Crown" in the Gulf of Tonkin) radar pictures were added to refine the tactical picture. Finally, radar and SIGINT data from specialist EC-121s- such as the famous radar early warning EC-121 that used the call sign "Disco"- was also relayed to the Teaball specialists as well. Also little known was a US capability to trigger the IFF systems of the MiGs so they could be easily tracked. The stream of data from all these sources made use of a top-secret NSA computer system called "Ironhorse" that was designed to analyze and synthesize all the data to create a cohesive tactical picture that was then displayed on the map screens for the Teaball controllers to relay via another radio relay RC-135 to US pilots over North Vietnam. Once the system was up and running, the delay was as little as 45 to 60 seconds before the Teaball controllers were issuing advisories to US pilots!

"Combat Lightning" was one many specialist KC-135 variants used

Each combat air crew, regardless of service branch, were notified of a discrete UHF channel to monitor that advisories from the Teaball control center were broadcast. Teaball controllers also knew the call signs of each and every combat mission for that day going into North Vietnam. Positions of VNAF MiGs were given in relation to a notional point called the "Bull's Eye" which was Hanoi. Distance and bearing from the Bull's Eye was given and air crews often programmed the Bull's Eye into their aircraft's own navigational equipment. "Blue Bandits" were MiG-21s, "White Bandits" were MiG-19s, and "Red Bandits" were MiG-17s. The code word "Green Bandit" indicated an exceptionally experienced VNAF MiG pilot was airborne. "Heads up" meant MiGs were nearby. Teaball controllers and analysts noted that certain combat flights were targeted especially heavily by the MiGs at times, and these US air crews were designated "Queen for a Day". A Teaball controller might inform a flight of F-4s about "Red Bandits, 25 miles SE of Bull's Eye, heading NE 300 knots" over a designated UHF channel. In effect, the Teaball controller acted as a GCI controller for the US pilots, constantly feeding them information on the position and action of any MiGs nearby to allow the US pilots to exploit the situation.

Lt. Col. Kirk briefed every unit that was flying combat missions over Vietnam and warned them explicitly "Pay attention when I call you on that channel!" Within the first month of Operation Teaball's operation, American fighters had moved from a 1:1 kill ratio to a 3:1 ratio and by the end of the Linebacker operations, the ratio had risen to 4:1 in favor of US air crews. The system saved many an air crew's life in the skies over North Vietnam, to the point that inbound flights often checked in with the Teaball control center once they had taken off to be sure they had their call signs!

Operation Teaball was one of the earliest and most successful uses of data fusion and what today we would call "network-centric" warfare- to use diverse data collection sources fused together to give situational awareness to our men and women in combat. It was the first time that such diverse sources of intelligence that were once the sole realm of distant analysts in the United States were used to deliver real-time actionable information to win battles. 

Sources: The Linebacker Raids: The Bombing of North Vietnam, 1972 by John T. Smith. Arms and Armour, 1998, p95-97. Air Force Magazine, July 2008, Volume 91, Number 7. "The Teaball Tactic" by Walter Boyne.

The Very Brief Career of the B-57 with the VNAF

In April 1964 the 8th Bomb Squadron and the 13th Bomb Squadron arrived at Clark AB in the Philippines as tensions in Indochina began to escalate. The Gulf of Tonkin incident was still four months away when the Martin B-57 Canberra jet bombers of the two squadrons took up residence at Clark. In the following month, it was decided that a select group of three South Vietnamese Air Force (VNAF) officers led by Major N. N. Bien would begin introductory training on the B-57 with the two USAF squadrons at Clark. At the time there was a great deal of hesitation on the part of the administration of President Lyndon B. Johnson on supplying the B-57 to the VNAF as it was thought that it would unnecessarily escalate tensions in the area. Despite the prejudicial stereotypes of many USAF personnel of the day on the quality of the pilots of the VNAF, this first group of three pilots turned out to be remarkably proficient and experienced in combat operations as they had all flown combat missions in A-1 Skyraiders and had jet experience from their flight training in France. 

As this first group of VNAF pilots were winding up their training at Clark AB, the Gulf of Tonkin incident took place in August 1964 that would bring American combat forces into direct confrontation with the North Vietnamese for the first time. The 8th BS and 13th BS alternated rotations to Bien Hoa AB outside of Saigon and the presence of the B-57s was thought might offset the presumed presence of North Vietnamese Ilyushin Il-28 light jet bombers. The next group of three VNAF pilots were then slated to take "Familiarization Training" with whichever USAF B-57 unit was on rotation at Bien Hoa who would fly their B-57s to Tan Son Nhut Airport in Saigon. Unlike the first three VNAF officers who were proved to be highly competent, this next group of three pilots were more for show than anything else as they were the flamboyant General Nguyen Cao Ky, head of the VNAF (and later Premier of South Vietnam), and two officers that were subordinates of General Ky, one in charge of Ky's security and the other in charge of the VNAF command post in Saigon. Their training was considerably abbreviated and consisted of only three days of ground school, a day and a half of aircraft familiarization on the ramp at Tan Son Nhut, and another three to four days of flying with an American pilot in the back seat of the B-57. As as typical for General Ky, on the the completion of their "training" he took the USAF instructors tiger hunting on elephants in the Central Highlands of South Vietnam!

It wasn't until August 1965 that the formal announcement was made that the B-57 was going to be operated by the VNAF. At a formal ceremony on 9 August 1965 at Tan Son Nhut, a USAF B-57 was flown in and repainted with VNAF insignia and a prominent South Vietnamese flag on the tail. The "U.S. Air Force" titles were removed but were obvious from the shiny areas left behind where the lettering had been buffed off. This B-57 was displayed with all the various armament stores it could carry, including one inadvertently armed 500-lb bomb! Before the ceremony, three dual trainer B-57Cs were flown in from Clark AB in the Philippines and repainted with VNAF markings. General Ky, who by now was the Premier of South Vietnam, and the previously trained pilots were given quick familiarization training to perform a fly-by during the ceremony. Having taken off before the ceremony, each pilot had an American instructor in the back seat. During the formation fly-by, Ky himself had to relinquish control of "his" B-57 to his instructor as he had not been present during all of the previous day's familiarization training. After a spirited fly by and landing, once the B-57Cs landed and were at the far end of the runway and out of sight of the assembled guests, the USAF instructor pilots climbed out of their back seats and the three jets were taxied to the ceremony area by their VNAF pilots and Premier Ky, which of course had the desired propaganda effect. As soon as the ceremony ended, the three B-57s had their USAF markings reapplied and were flown back to Clark AB. 

Major Bien of the VNAF, officially in charge of the VNAF portion of the B-57 training, brought another group of 12 pilots and 12 navigators to Clark to begin actual bona fide training in the B-57. Of historical interest, there were also two Philippine Air Force navigators in the group as well as a "gesture of thanks" to the Philippine government for allowing their country to serve as a vital rear logistics area for the war effort. As each VNAF pilot and navigator completed their training at Clark, they were then sent to Bien Hoa with either the USAF 8th Bomb Squardon or the 13th Bomb Squadron (whoever was on rotation at the time) and were paired up with either experienced USAF pilots or navigators to fly combat missions. There were VNAF-marked B-57s based at Bien Hoa AB, but they were few in number and always flown under USAF command.

At this point Premier Ky felt that the VNAF B-57 program was not getting the visibility he desired and wanted in order to boost the morale of the South Vietnamese military. On 29 October 1965, the Armed Forces Day for South Vietnam, five B-57s were flown in from Clark and repainted in VNAF markings. Fully armed and fueled and crewed entirely by USAF personnel, the five Canberras took off from Da Nang, struck a suspected Viet Cong base and then flew 300 feet at nearly 300 knots up the main boulevard in Saigon and over the Presidential residence. This gave Premier Ky his propaganda coup even though not one crewman on that mission was a VNAF officer!

Despite this, morale amongst the VNAF contingent in the Philippines was low and USAF instructors were constantly being frustrated by the lack of discipline of the second group which included frequent claims of illness and even complaints about the extreme maneuvers needed in exploiting the B-57's strengths. Matters came to a head when one VNAF pilot crash landed his B-57 at NAS Cubi Point while doing touch-and-gos. But before the issue of morale and discipline could be sorted out, the charismatic leader of the VNAF contingent, Major Bien, was killed in a freak accident when his B-57 diverted to Pleiku AB. Unable to restart his engines due to the inexperienced VNAF ground crew installing the engine starter cartridges incorrectly, the ground crew elected to manually push his B-57 to another area of the ramp for further attention. Unfortunately, the engines powered the hydraulic system and the brakes were inoperable. The ground crew lost control of the B-57 and in an effort to avoid getting injured, Major Bien jumped from the open cockpit only to be run over by one of the main wheels. 

With Major Bien's death, the rest of the VNAF contingent at Clark refused to continue with the B-57 program and the USAF closed down the VNAF B-57 program on 20 April 1966, only seven months after the program was publicly announced. The remaining VNAF B-57s were repainted in USAF markings and returned to service with the 8th and 13th Bomb Squadrons in USAF markings and American crews. The most potent aircraft that the VNAF had been given had been an utter failure, a victim of political grandstanding by the South Vietnamese government. 

Source: Martin B-57 Canberra: The Complete Record by Robert C. Mikesh. Schiffer Military History Press, 1995, p99-104.