Deep Sea 129: The price Silent Warriors pay
“Our conduct in the EC-121 crisis was weak, indecisive and disorganized”
Henry Kissinger
EC-121M mission background
Back in 1969, the best way to get information about opposing forces was to put cryptologists on aircraft and fly them over international waters, but close to the borders of these forces. The idea was to collect communications intelligence (COMINT) and electronic intelligence (ELINT) from opposing forces, all together known as signals intelligence (SIGINT).
SIGINT operations in the US were the responsibility of the National Security Agency (NSA). Each of the military services provided people and equipment, including aircraft and ground stations, to contribute to the SIGINT mission.
The Navy operated the EC-121M aircraft and others as part of the Peripheral Airborne Reconnaissance Program (PARPRO). These aircraft were assigned to the Navy’s Fleet Airborne Reconnaissance Squadron One (VQ-1) at Atsugi Naval Air Station (NAS), Japan. The SIGINT crew was provided by the Naval Security Group (NSG) Detachment at Naval Support Facility Kamiseya, Japan.
The aircrew was young, smart, talented, brave, well-trained, and well-briefed. Some were on their first hitch in the military. The crew for the mission on April 15, 1969, was larger than usual to train new replacements.
The crew knew their unescorted and unarmed missions were dangerous. They knew hostile events could occur. They did have the capability to monitor North Korean reactions, which could make escaping an attack feasible. I presume the crew was intercepting North Korean tactical air communications and knew MiG-21s were reacting to them. The crew may even have intercepted the order for the MiG-21 to fire.
The pilots had a certain number of evasion options, limited given the size of this aircraft and slow speeds, but they had some options nonetheless.
Everyone was trained on bailout procedures, survival techniques, and, in the event of capture, resistance tactics. I am sure they were confident US forces would come to their rescue in the event they successfully bailed out, though they understood such forces might not always be nearby.
They knew they were involved in the Cold War, a participant in what was really a secret war. They also knew the enormous value of the intelligence they collected.
The US knew very little during the early years of the Cold War about Soviet, Chinese, Eastern Bloc, and North Korean military capabilities and force disposition. That meant, among other things, the US Air Force and Navy would have to send out vulnerable reconnaissance aircraft close to an opposing force’s frontiers. For a lot of technical reasons, much of the intelligence collection had to be done from the air by military aircraft and along the periphery of target countries. That remains true to this day.
Most aircraft conducting these missions were slow and vulnerable, usually unarmed, and usually without escort. Their missions were long, often exceeding eight hours. Risks of mechanical failures were always present, as were hostile reactions. This also remains true today.
As opposing air forces received better and better fighter aircraft and as they improved their overall air defense systems, the US missions became increasingly more dangerous. Veterans have told me fighter aircraft would often come so close that the crews could see each other nearly face-to-face. Furthermore, opposing force fighters would develop harassment techniques and maneuvers, often wing-tip to wing-tip. I am told by veterans of USAF reconnaissance that MiGs would even fly under the reconnaissance aircraft's wings.
Larry Tart and Robert Keefe, writing The Price of Vigilance, wrote:
To the Soviet, Chinese, and North Korean leaders, all foreign aircraft (and ships) that approached their borders were suspicious- plain and simple. They viewed all intruders as spy missions and responded with hostile actions. They would challenge such flights on a regular basis. One could never be sure when an attack might come. There is no such thing as a routine reconnaissance mission, just as for police, there is no such thing as a routine stop.
“Deep Sea 129” Attacked, April 15, 1969
The EC-121 to be discussed used the callsign “Deep Sea 129,” launched from Naval NAS Atsugi, Japan, at 0700 hours local time, Lt. Commander James Overstreet, USN, in command. She had nine officers and 22 enlisted electronic technicians and Russian and Korean linguists aboard. One of those was a Marine, the rest USN. The mission was to collect SIGINT, mainly ELINT, though the linguists did intercept communications intelligence (COMINT).
The plan was to fly to a point off North Korea's northeastern coast, then fly two-and-a-half orbits along a 120 nm elliptical track and recover at Osan AB, Republic of Korea (ROK), about 30 miles south of Seoul. The scheduled flight duration was 8.5 hours.
This was a route the Navy had been flying for two years, and some 200 similar missions were flown in this area during the first three months of 1969. Mission rules of engagement were that the aircraft could not approach closer than 50 NM to the North Korean coast. Friendly radar coverage would be available during part of the flight from Japan and South Korea. Multiple Army, USAF, and USN ground-based COMINT collection, analysis, and reporting stations monitored North Korean communications that might indicate an enemy reaction to the flight.
Furthermore, the USN Korean linguists aboard the aircraft could monitor the air-to-ground communications between MiG pilots and their Ground Control Intercept (GCI) station.
Historically, North Korean fighters were not permitted freedom of action, but instead took all their flight instructions from a GCI controller. The GCI controller would have had to issue the order to fire by radio, along with all kinds of other instructions. One would have expected the EC-121 linguists to have picked up these communications and would have had an idea of where the MiGs came from, their flight tracks, and even the commands the GCI controllers were issuing.
Shortly after the EC-121 arrived in its elliptical orbit area, North Korean fighters reacted at 1035 hours, but far to the southwest. They did not show any hostile intent; the mission continued, and the fighters returned to their bases.
Some six hours into the flight, two North Korean Air Force (NKAF) MiG-21 interceptor fighters launched from East Tongchong-ni near Wonson, DPRK. It turned out the North Koreans had moved two MiG-21s from Pukch'ang-ni Airfield in the west to Hoemun-Ni Airfield in the east 18 days before the shoot-down. The deployment base at Hoemun-Ni was a MiG-15/17 training base. While this was an unusual deployment, it did not seem to carry much weight in analysts’ minds. Analysts in Okinawa concluded the aircraft were sent there for training. There was no NKAF tactical unit at Hoemun. The EC-121 crew was not briefed on this deployment, a grave omission.
An Air Force COMINT ground collection site tracked the MiGs, which were moving quickly across the Sea of Japan, and then the site noted they were within 50-55 nm of the EC-121. In retrospect, the MiGs timed their flight so they came at the EC-121 while on the northernmost part of its orbit, the point where it would be closest to Hoemun. One of the MiGs flew a defensive patrol no closer than 60 nm from the EC-121 while the second MiG proceeded toward the EC-121.
The USAF site alerted the EC-121 crew through what are known as advisory warnings. However, the aircraft did not have communications equipment to acknowledge receipt of the warnings. Therefore, it is not known whether the crew received them.
However, in his book Melvin Laird and the Foundation of the Post-Vietnam Military, 1969-1973, Richard A. Hunt says three advisory warnings were sent out, and the EC-121 acknowledged receipt of the third, but the EC-121 was lost from radar shortly thereafter.
VQ-1 had received the warning messages and alerted Deep Sea 129 that it might come under attack. It ordered the skipper to abort and return to home base. Commander Overstreet turned the aircraft away from North Korea and headed toward Japan. But the radar tracks of the second MiG merged with the EC-121. The EC-121 disappeared from radars two minutes later. The second MiG shot it down about 80 nm from the North Korean coast.
Shortly after the advisory warnings were issued, Brigadier General Arthur Holderness, USAF, commander, 314th Air Division, Osan AB, ordered the launch of two F-102s to be placed on combat air patrol (CAP) about 100 nm from the incident area. The F-102s positioned themselves in the vicinity of the EC-121's expected flight route on its final leg to Osan. They were to search for the EC-121 and rescue it from harassment or attack if it were still in flight. The F-102s were airborne about 17 minutes after the EC-121 had been shot down.
Except for the scramble of the two F-102s, further US reaction was muted. There was an expectation that the EC-121, if under attack, would rapidly descend below radar coverage. The NKAF needed radar coverage to instruct the MiGs where to fly and what to do. The idea was to hide the EC-121 from the GCI controller's radar, inhibiting him from directing the MiG.
An Air Force COMINT site sent a CRITIC message about an hour after the shoot-down, which went to the National Command Authority (NCA) and others, saying Deep Sea 129 had disappeared. The NCA is a term used by the Department of Defense (DoD) of the US to refer to the ultimate source of lawful military orders. The NCA comprises the President of the United States (as commander-in-chief) and the Secretary of Defense jointly, or their duly deputized successors.
National Security Advisor Dr. Henry Kissinger informed President Nixon. DPRK radio said the aircraft intruded into NK airspace. Search and Rescue (SAR) proceeded with minimal effect.
Three Soviet destroyers joined the search. One of the destroyers, the Vdokhnvenie, found some wreckage and two bodies. The Soviet destroyer transferred the two bodies to the US destroyer USS Henry W. Tucker. The Tucker arrived with the bodies of two members, Lt. jg Joseph R. Ribar and Aviation Electronics Technician Richard Edson Sweeney.
Another Soviet ship engaged in the SAR found some debris, laid it out on the deck, and a US aircraft overflew to take photos. The USS Dale picked up some pieces of the fuselage. The fuselage was riddled with shrapnel holes.
North Korea went to a high state of alert, but it appeared to be a defensive posture. NAS Atsugi was closed and placed on lockdown. Naval reconnaissance aircraft that had staged from Atsugi were recalled.
The US was completely surprised, blindsided by the shoot down.
Threat Assessment
General Charles Bonesteel, USA, in 1969, serving in three capacities as Commander of U.S. Forces Korea (USFK), Commanding General Eighth US Army (EUSA), and Commander-in-Chief, UN Command Korea (CINCUNC), warned about the possibility of a hostile North Korean reaction to US reconnaissance flights, even if they were over international waters. He said:
“I warned CINCPAC (Commander-in-Chief Pacific) about four days before the plane (USN EC-121) was shot down. I was specifically talking of Air Force flights, but we knew the North Koreans were doing something that was damned suspicious. I recommended they have a very close watch or tie-in with radars watching … airfields, and if they got a scramble to get the hell out of there.”
Bonesteel knew the DPRK had provoked the US and the ROK many times on the peninsula between 1966 and through March 1969. US and ROK soldiers were killed during these provocations. The DPRK’s overall strategy at the time seemed to be to cause an insurgency in the South and weaken the US-ROK relationship. The DPRK's strategy, mainly involving unconventional warfare, did not work, and there was a significant military purge.
All that said, the USAF and USN had flown 190 similar missions from January through March 1969, forty-nine of which were Navy VQ-1 reconnaissance flights, and there had been no hostile North Korean reaction. Risk assessments considered a hostile intercept action unlikely.
Bonesteel had no authority or control over the EC-121 mission. Those fell to the Joint Chiefs of Staff (JCS), the CINCPAC, and in this case, the Commander-in-Chief Pacific Fleet (CINCPACFLT). This was a signals intelligence (SIGINT) collection flight, mainly an Electronic Intelligence (ELINT) flight, so the National Security Agency (NSA) did not have any control over it either.
There has long been a dearth of knowledge about North Korea, often called the "Hermit Kingdom." The State Department’s Bureau of Intelligence and Research wrote the following after the seizure of the USS Pueblo in 1968:
“North Korea is the most denied of denied areas and the most difficult of all intelligence targets. Estimates of North Korean strength, intentions, and capabilities, therefore, cannot be made with a high degree of confidence.”
