Suppression of Enemy Air Defenses: part one: The Vietnam War!

9 Jun

The Suppression and/or Destruction of Enemy Air Defenses (SEAD or DEAD) is one of the lesser-known missions fought in the air by highly trained crews equipped with the latest electronic warfare equipment.

Its origin dates back to WW2 and has evolved as one of the most important components of any air raid in modern warfare. Following the adage, the best defense is a good offense. A SEAD flight would act as bait, to put the enemy radar operators on the defensive by jamming them and, if possible, destroying their radars, thus protecting friendly bombers on their way to their targets.

Because pilots were mimicking the tactics of a predatory animal, Vietnam area USAF pilots called their Squadrons the “Wild Weasel”.

In this first part, I will study the birth of the Weasels until the end of the Vietnam War.

Churchill Wizard War

During the Battle of Britain, numerically inferior RAF pilots who faced the Luftwaffe managed to intercept most of the raids thanks to the 21 Chain Home early detection radars.

This extremely innovative ground-based interception system birthed the concept of a country or a theater-wide Integrated Air Defence System (IADS). To counter and reduce its effectiveness, German fighters flying at low levels started to bomb the radar stations, opening holes for the bomber to fly through undetected.
These radar suppression missions were key to preventing RAF fighters from being vectored towards Kampfgruppe raids. Despite their best efforts, the Luftwaffe could not destroy enough of them to impose air superiority over the Channel.

Great Britain was saved.

A couple of years later, Germany, being on the receiving end of Allied bombers, set up the Kammhuber line. This overlapping radar and searchlight network was needed to protect the eternal Reich industrial capability 24/7.

Kammhuber Line

In August 1943, a US mission over the Schweinfurt involving 376 B17 sustained unacceptable losses to over 300 German fighters vectored by the ground controllers.
60 bombers were shot down and 95 were heavily damaged. With 40% of the attacking force out of action, raids like this could not be repeated. Several measures had to be put in place to counter the German defensive network.
5 months later, long-range P51 Mustangs were ready in sufficient numbers to escort Allied bombers to Germany and back, but they also benefited from the presence of aircraft whose sole purpose was to find, blind and destroy enemy radars.

In November 1943, the Royal Air Force formed its No. 100 Special Duties Group specialised in Electronic warfare. Several B17F were equipped with aluminium strip dispensers to blind enemy radar, while Typhoons fighter bombers were used for the first time with radar direction finding equipment to locate German radar and mark it with smoke rockets for Mosquito light bombers to destroy them.

Another innovative idea was taken from the RAF and quickly grown to an industrial size by their US cousins. In March 1944, the Radio Counter Mesure unit of the Eighth Air Force was formed with 37 B17F ferret EW aircraft and would play an important role during the D-Day landing.

The most dangerous whack-a-mole game was born, but it will start to thrive in Vietnam, to counter a brand-new threat, the Soviet Surface to Air Missile (SAM).

Operation Rolling Thunder (2 March 1965-2 November 1968)

SAM’S Song

WW2 ended before the Germans could field the 7-ton “Wasserfall”, the first guided Surface-to-Air Missile (SAM) designed to explode in the middle of a bomber formation.

The guidance system was primitive, but the size of the warhead was enough to destroy or cripple an entire formation of tightly packed bombers.

The Soviets took the concept further with the S75 Dvina.
It became famous by downing several US-built U2 reconnaissance airplanes over Russia and Cuba.

The First units were quickly deployed in North Vietnam as a cost-effective system, to challenge US Airpower.

The SA-2 system is built around a 2.3 ton, 10 m-long missile flying at Mach 3.5. It was designed to intercept bombers flying from medium to high altitudes up to 28 miles away. Each missile site included 6 ready-to-fire missiles on their launcher, a radar and a control van. The density of SA-2 sites over North Vietnam quickly made traditional medium or high-level carpet bombing quite dangerous.

**S75 Dvina, Nato code name SA-2 Guideline.**

The Vietnamese could rely on Soviet intelligence to detect incoming raids, but also on Soviet SAM specialists who manned the majority of the 48 SA-2 sites deployed at the end of 1965.

They were keen to learn how to defeat the best-trained air force equipped with the most advanced aircraft on the planet with their new missiles.

Ten soviet training centers with 2200 Warsaw Pact missile experts were set up in North Vietnam.

They did not have to wait for long.

On 24 July 1965, Senior Lt Konstantoniv launched 2 SA-2 towards a 4-ship F4 Phantom formation, hitting the same one twice. Two kills were credited to the SAM division. The USAF only lost one aircraft, but the three were damaged by the blast.
The pilot, Captain Richard Keirn, survived and became a POW for the second time. The first time was in Germany 20 years earlier.

The most successful identified Soviet SAM operator was Lt Shcherbakov who received the Order of Lenin for shooting down between 6 and 12 US aircraft (depending on sources) over 20 engagements.

In 1965, North Vietnam sent 1000 staff to be trained on the SA-2. They were ready to be deployed in early 1966.

China’s participation was also important, with 150,000 men equipped with 130mm, 57mm, 85 mm and 23mm anti-aircraft guns (named Flak or AAA).
They also had a few dozen Migs, used under strict ground control for hit-and-run missions, but they were vastly outmatched, despite a few successes.

After these first losses, quickly followed by a few others, the US Air Force launched a retaliatory strike against the SAM sites on July 27th with 46 F105 bombers supported by 58 other aircraft.

Not only did they lose 6 bombers to ground fire, but they only destroyed dummy sites!

The US Navy took their turn with their better-equipped aircraft already equipped with the first Antiradar missile, the short-range AGM 45 Shrike.
On August 12, 1965, the US Navy launched 124 aircraft over 2 days to hunt for SAM sites.
But with little success, they failed to locate any sites and, during the second day, lost seven aircraft from intense AAA (Anti Aircraft Artillery) in 45 mn.

A4 Skyhawks VA-23 Iron hands mission with AGM 45 Shrike anti-radar missiles

The lack of success was due to several factors:

- Both the USAF and US Navy lacked airborne jammers or even SAM detection equipment in 1965. So low-level tactics were enforced, exposing aircraft to a murderous AAA fire for most of their flight. Beyond the aircraft losses, it was not uncommon for more than 50% of the aircraft involved to receive combat damage.

-The Vietnamese used very effective camouflage, deployed many dummy SAM sites, and frequently relocated the real ones. These “Maskirovka” tactics ensured that the 7 available SAM sites deployed around Hanoi could survive.

The US forces eventually destroyed the first and the second SAM sites in late October and early November with 6 additional dummy ones but at the cost of three F105, two Crusaders, two F4 Phantoms, one Skyhawk plus damage to many others.

US headquarters already knew that 56 SA-2 sites were being deployed in late 1965. The air war could not be won with such an exchange rate.

By the end of the year, the US had lost 185 aircraft, 153 to anti-aircraft fire, only 11 to SAM and 4 to Migs.
The SAM kill tally was small, but their real contribution was to help AAA gunners have lots more targets at low levels to shoot at!

The US had to quickly develop an entire family of supporting aircraft to monitor and defeat the Russian-built air defense network.

The need for SEAD!

Wild Weasel was THE most important program at Egling AFB at the time.
The mission was to detect, locate, and then visually acquire SAM sites for a rocket, gun or napalm run over the missile site, always heavily defended by AAA.

During training with their first specialised aircraft, the F100F SuperSabre, the Secretary of the Air Force, Harold Brown, visited the first pilots before they went to South East Asia.

He introduced them to their new mission quite bluntly:

“If the SAM don’t get you, they will force you down from your attack altitude to within range of the Viet Anti-Aircraft-Artillery.”

Many pilots could not believe what was asked of them. It seemed almost like a suicidal mission.

The squadron patch reflected the initial reaction of one of the first crew when he heard the mission objectives.

"You want me to fly in the back of a tiny little jet with a crazy fighter pilot who thinks he's invincible, home in on a SAM site in North Vietnam, and shoot it before it shoots me? You've gotta be shittin' me!”

This became the unofficial motto of this very dangerous profession“YGBSM”.

40 years of aircraft development to fly higher and faster has been stopped, by this new SAM threat. To survive, this new breed of pilots had to leave the relative security given by altitude and fly back into the dreaded “Flak” (German WW2 air defense guns).
This Charybde and Scylla irony made these pilots at the mercy of 6000 guns spread over hundreds of kill sites.

Their only chance was to fly at near supersonic speed, so low that they called themselves the “River Rats”.

First In Last Out!

Weasel One eventually got deployed in November 1965.

Their mission to protect their fellow pilots during each raid soon became invaluable.

A typical Wild Weasels Flight consisted of one F100F tasked to detect and lead a flight of several bomb-equipped F105D Thunderchiefs to destroy the target.

Every raid over North Vietnam was a complex synchronised ballet where hundreds of aircraft coming from different bases had to regroup before their attack ran on North Vietnam.

- US Electronic warfare aircraft were listening for SA 2 sites' radar emissions and radio communications between MiGs and SAM sites often in russian.

- F4 Fighters with 8 air-to-air missiles each had to be vectored towards the Migs as soon as they were detected to engage them in dogfights.

- Last but not least, Iron Hand patrol with “Wild weasel” aircraft flying at low altitudes in front of the strike group to act as bait for the SA-2 site to use their missiles on them instead of the bombers.

The detachment successfully destroyed 8 SAM sites and forced countless others to be off the air in fear of being detected and destroyed.

However, this initial concept validation phase was not without risks. By March 1966, more than half of the 7 F100F had already been shot down.
From the first class, 16 aircrew members, four had been killed, two were prisoners of war, three had been wounded and two had quit.

The survivors were quickly sent back to Eglin to set up the Weasel School for the second generation to learn from them.

Wild Weasel 3

The Mighty Thunderchief

Weasel 2 and 3 programs were launched simultaneously, but Weasel 2, based on the F4C Phantom, took years to be fielded because of the aircraft's systems complexity. The Weasel 3, based on the older but easier-to-modify F105F, was ready in March 1965.

The second generation of Weasel pilots could learn from the few survivors of the first class. They were about to be deployed with a much more capable weapon platform.

The F105F could fly faster, and further, had a better payload and was equipped with a weapon that could destroy a SAM guidance radar without flying through the flak kill zone, the AGM 45 Shrike. This anti-radar missile uses the SAM's own radar emissions to track it down and destroy it.

The suppression (SEAD) became gradually a more important and more survivable mission than the destruction (DEAD) of enemy sites, as fighters did not need to get too close into the Flak killing zone. Their mere presence was enough to keep the SAM’s radar off.

5 aircraft with 7 crew went into action in May 1966, joined quickly by 6 more aircraft and 8 crew in June.

Going downtown

The SAM operators also improved their tactics.

-SAM sites were set up in dense and overlapping patterns, so they could protect each other. Any Weasel attacking a site could be engaged simultaneously by missiles coming from 3 different directions, leaving the aircraft very little time to attack. To survive, the F105 pilot had to fly at a very low altitude and out-turn any missile flying at Mach 3.5, a difficult task against one, extremely risky against three. Did I mention the constant AAA trying to shoot them down?

SAM operators started to use passive launch and fake firing tactics.
-SA-2 radar has 2 modes of emission, a search mode and a tracking mode used for missile guidance. The F105 crew could differentiate both. If the track mode was detected, the SAM radar was tracking your aircraft, potentially guiding a missile towards you.

Faking a SAM launch would entice the pilot to launch his own Shrike missile towards the radar to destroy it. The SAM operator would then turn his radar off, making The Shrike missile go blind.

Result: one missile lost. A small win for the red team!

To counter this tactic, an experienced Weasel would wait several seconds to confirm if it was a fake or a real launch.

Quite a risky bet, when SA-2 flight times last 15–20 seconds.

Experienced SAM operators would launch the missile without radar tracking (passive launch), and only lock the radar a few seconds before impact for terminal guidance, to reduce the pilot's reaction time even more.

The nightmare situation for any pilot was to work against multiple SAM sites working together.
Only one SAM site would use its radar as bait, to bring the attacking planes into a SAM and AAA trap.
When the plane was close enough, the radar of all the sites would suddenly activate around the poor pilot, leaving him very little chance against several incoming missiles.

Flying over North Vietnam was a very dangerous business. In only 4 months, 5 of the 11 crew were shot down.

It was statistically impossible for them to survive the 100-mission mark to go home.

The saying among Thud pilots was that “By your 66th mission you’ll have been shot down twice and picked up once.”

But the concept was working. Wild Weasel missions were in high demand during any raid “Downtown” to Hanoi. Their job was to open the infamous Route Package 6 for the bombers.
At the end of 1966, around 50 EF 105 Wild Weasel were deployed in SEA.

USAF losses in 1966 continued to increase, despite SAM kill efficiency going from 5.7% in 1965 to 2.8% in 1966. The vast majority of the losses came from AAA with 240 aircraft shot down.

Before Stealth, optical camouflage was tested on one aircraft.
The story goes that the plane was eventually lost, never to be seen again!

1967 Attrition time

In the fall of 1967, EF-105Fs began to be upgraded to the definitive Wild Weasel Thunderchief version, the F-105G.

Internal jammers were installed. Thirty aircraft were fitted with pylons to carry the AGM-78 Standard anti-radiation missile. It was a massive improvement over the Shrike, as it could be launched well outside the SA-2 engagement range. It also stored the SAM radar position to hit it even when the SAM radar is switched back off.
On a typical mission, the F-105G carried two Shrikes on outboard pylons and a single AGM-78.

The weasel's squadrons flew hundreds of missions up north and were credited with 89 SAM site hits, and hundreds of others temporarily suppressed.

But again, the cost was enormous. 27 Weasels were lost and 42 crew were either MIA or KIA.

The most famous Weasel team was Major Leo Thorsness and Captain Harold Johnson.

Major Thorsness was the “old Weasel” for the record 90 missions that he had flown and survived.

Both crew members saw at least 53 SAM launched at them, not counting hundreds of AAA batteries and several close encounters with MIGS.

On 19 April 1967, they flew a 4h30 mission during which they destroyed 2 SAM radars, provided cover for their downed wingmen during an unsuccessful rescue operation, engaged 2 MiGs and shot one down with 20mm gunfire!
Later on the same flight, they escorted a damaged airplane to a tanker and eventually landed with no gas left.

11 days later, during their 92nd mission, they were both shot down by a MiG.

They had to wait for their release in March 1973 to be awarded the Medal Of Honor and the Air Force Cross respectively, for this incredible mission.

An analysis of the SAM's effectiveness over the years does pay tribute to the efforts of these crew. The last year of Operation Rolling Thunder was the costliest, but the SAM effectiveness was again reduced by 50%, validating the Wild Weasel dedicated squadron concept.

What the Weasels drivers needed urgently was a new aircraft. Very few F105 remained and they were not in production anymore.

For fear of escalation, the USAF would not strike any supply routes, harbour or missile depots in Hanoi, allowing North Vietnam an uninterrupted source of replacement for missile and gun ammunition.

The outcome of this campaign, according to Mark Clodfelter, was a net improvement in North Vietnam war-making capacities and had little measurable effect on their ability to support military ops in the south.

Linebacker I and II (9 May-29 December 1972)

The Evolution of Electronic Warfare between Rolling Thunder and Linebacker.

After the offensive launched by North Vietnam, the US government started the LineBacker operation with clear objectives:

Isolate North Vietnam from its sources of supply by destroying railroad bridges and rolling stock, in and around Hanoi and northeast towards the Chinese frontier. And for once, no targets in North Vietnam were off-limits.

The US Air Force brought 150 B52 Stratofortress bombers and almost 200 brand-new F4C Phantoms with revolutionary laser-guided bombs (LGB).

It was a huge gambit for the USAF. The B52 was the cornerstone of their nuclear deterrence. They were equipped with the most advanced electronic warfare equipment built to penetrate Soviet defense to drop their nuclear bombs over Moscow.

Hanoi 361st Air Defense Division was advised by Soviet Col-Gen Anotoliy Khyupenen, who arrived in Hanoi in 1972 to direct the Soviet air defense advisory effort. He convinced them to focus the SAM on the B52 only and to let the AAA take care of the tactical aircraft.

Shooting down a strategic nuclear bomber had massive political potential. He was also eager to see American Electronic Warfare in action.

USAF invested massively in helping the Wild Weasels in their mission.

Every raid was escorted with active and passive electronic jamming. F-4C Wild Weasels were used for the first time as thirty-six were deployed to help the surviving F105G.

A dozen fighters flying ahead of the raids always filled the sky with Chaff corridors of 50NM to blind enemy radars.

The Vietnamese reacted quickly against raids of more than 50 B52s with new tactics, exploiting the USAF habit of repeating the same template of operation for each mission: same routes, same formation, active jamming starting at the same time…
This predictability enabled the SAM sites to attack when the bombers were the most vulnerable.
According to Col-Gen Anotoliy Khyupenen, this was one of the major reasons for the B52 losses despite his praise of US Electronic warfare capabilities.

The US lost 49 aircraft to SAM in 1972.
The Air Force told Congress that only 13 B-52s were lost. But many more B-52s were too badly damaged to fly again. The overall B-52 number lost is likely to be between 22 and 27.

That’s 10- 15% of the available B52 force.
The US Strategic Air Command never acknowledged its “losses”; the bombers were too badly damaged to be flown again.

The Linebacker was a tactical success, but losses of that magnitude on such an important strategic asset could not have been sustained for much longer. More troubling is that the SA-2 was already an outdated system for the Soviets.

The Wild Weasel Mission kept on proving their worth, as 4244 SAM were fired in 1972, for a very poor hit ratio of 1 %.

Conclusion

The Wild Weasel concept was a success as they managed to steadily degrade the SA2 effectiveness below 1% between 1965 and 1972. Thanks to constantly improving tactics, better weapons and better Electronic Warfare equipment.

However, these results were obtained at a very high price for the Wild Weasels with 4 F100F out of 7, and 46 F105 out of 65 were lost with 35 crew members.

The exact number of SAM sites destroyed is uncertain. A Soviet general who served with the North Vietnamese air defense forces, claimed that they were provided with 98 missile systems and 7,500 missiles and finished the war with 45 sites and 2,300 missiles, ”An SA-2 site could be moved positions in 6 hours, and the use of decoy SAM site makes the count quite difficult.”

The biggest success of the SAM remains to have forced US pilots to fly low into the flak-kill zone, with a devastating 1500 aircraft lost by the USAF and US Navy during the war, to this relatively simple weapon.

The B52 losses while flying over Hanoi during Linebacker made the US Air Force realise that a medium-altitude conventional or nuclear raid over a heavily defended target was not the way to go.

A lot of effort went into the development of stand-off nuclear cruise missiles, to correct this situation.

These lessons were not lost to the Soviet air defense either. The PVO Strany was already fielding a new generation of mobile SAM systems. The Israeli Air Force would soon discover their capabilities during the 1973 Yum Kippour War.

So much for the duel between knights and their machines as depicted in Top Gun. In this new air war, pilots are back in the trenches, being shot at by everything North Vietnam could throw at them.

Fighter pukes make movies. Bomber pilots make history!

The next article, SAM Suppression during the 1973 Yum Kippour War

Mig 21 Interceptor are credited with a couple of B52 Kills

Sources:
https://www.usni.org/magazines/proceedings/1994/september/your-wing

Training Training training.
https://www.airandspaceforces.com/article/0710weasels/

-( 1950-1972)AAA in combat Colonel Mandeeo Singh ( book)

-Wild Weasel, the SAM suppression story. Squadron signal publication
- F105 units of the Vietnam War. Osprey

- PATTERNS AND PREDICTABILITY: THE SOVIET EVALUATION OF OPERATION LINEBACKER II by Dana Drenkowski and Lester W. Grau.

Thibaut Mallet https://midhipnews.org/

Suppression of Enemy Air Defenses: part one: The Vietnam War!

Churchill Wizard War

Kammhuber Line