Feature Article
Was It the Radar?
Respectfully Revisiting the 1967 US Navy USS Forrestal Carrier Disaster
Part 1
By Brian M. Kent, Ph.D.
vector illustration of a naval ship carrying fighter jets, one of the fighter jets is in flight
I

n 1967, while on patrol in the Gulf of Tokin, the United States Navy Carrier USS Forrestal was executing wartime missions over North Vietnam. At 10:45 AM local time, the ship was preparing to launch more than 27 A-4 Skyhawk and F-4B Phantom Fighter jets, all fully fueled and armed with a mixture of iron bombs, precision missiles, and Zuni rocket launchers. At 10:51 AM, an F-4B experienced an un-commanded Zuni missile launch on the flight deck, striking a neighboring A-4 and starting a fire causing a series of devastating secondary explosions. Quenching the fire nearly capsized the ship, which was ultimately saved through the heroics of the sailors who served aboard the Forrestal.

Although the US Navy conducted an extremely thorough accident investigation, many follow-up technical articles in the aerospace and NASA literature, including current EMI design books, blamed the initiation event on EMI from on the on-board AN/SPS-43 VHF search radar. This article is aimed at reinforcing the official USN record regarding the accident’s true root cause. The Forrestal’s many “lessons learned” led in part to the creation of an entirely new discipline called “insensitive munitions” within the Electromagnetic Compatibility community and is therefore a critical event to understand.

Dedication
This article is humbly dedicated to the families, relatives, and friends of the 134 Sailors killed and 167 severely wounded on July 29, 1967 aboard the USS Forrestal. We honor the hundreds of additional survivors who suffered from a lifetime of PTSD and “survivors’ guilt.” The bravery and heroics of the Sailors who saved the USS Forrestal and its 5,400 lives by quenching the fire and preventing the carrier from capsizing cannot possibly be overstated.

On July 29th, 1967 the Navy Carrier USS Forrestal (CVA-59) experienced one of the most tragic accidents in the modern US Naval aviation history. While preparing to launch a 27-plane strike mission into North Vietnam, an un-commanded Zuni rocket was launched on deck from an F-4B fighter, striking an A-4 Skyhawk aircraft across the deck, causing an initial fuel-fed fire. Within 94 seconds, huge secondary explosions rocked the carrier launching one of the most devastating fires in US Navy history since the Second World War. This accident and the lessons the US Navy learned from it completely changed everything about modern US Naval aviation from fire-fighting to launch procedures to designing weapons to be hardened from electrical faults and direct contact with fire.

The 1967 Forrestal accident investigation correctly identified the root causes of the fire. However, over subsequent years researchers and engineers began to insert or augment their own perspectives, biases, and conclusions about the fire which upon close inspection are in direct conflict with the original Forrestal accident conclusions. Several citations and alternate history myths have only grown over the years to the point that original root causes were either lost or highly distorted. To illustrate, I have randomly chosen three such references.

In July 1995, a NASA EMC Design book produced by NASA’s Marshall Space Flight Center [1] published the following version of the Forrestal accident and its conclusions (note the underlined text below is the author’s emphasis):

“In 1967 off the coast of Vietnam, a Navy jet landing on the aircraft carrier U.S.S. Forrestal experienced the un-commanded release of munitions that struck a fully armed and fueled fighter on deck. The results were explosions, the deaths of 134 sailors, and severe damage to the carrier and aircraft. This accident was caused by the landing aircraft being illuminated by carrier-based radar, and the resulting EMI sent an unwanted signal to the weapons system. Investigations showed that degraded shield termination on the aircraft allowed the radar frequency to interfere with routine operations.”

In 2006, Clayton[2] updated a foundational EMC Design book for the IEEE. On page 13 in the introductory chapter is this reference to the USS Forrestal fire:

“On July 29th, 1967, the USS Carrier Forrestal was deployed off the east coast of North Vietnam. The carrier deck contained numerous attack aircraft that were fueled and loaded with 1,000 lb. bombs, as well as air-to-air and air-to-ground missiles. One of the aircraft missiles was inadvertently deployed, striking another aircraft and causing an explosion of its fuel tanks, and the subsequent death of 134 service people. The problem was thought to be caused by the generation of radio frequency (RF) voltages across the contacts of a shielded connector by the ship’s high-power search radar.”

In 2008, an IEEE EMC briefing published by Joffe [3] had the following observations about the Forrestal accident:

“On July 29, 1967, USS “Forrestal” cruised off the coast of North Vietnam. Its jets had already flown more than 700 sorties and there was no reason to expect this day to be any different. Not threatened by enemy aircraft, the A4 “Skyhawks” on the deck were loaded with fully fueled two 1000 lb. bombs, air to ground and air to air missiles. Somewhere on the deck of that carrier, attached to the wing of an aircraft, was an improperly mounted shielded connector. As the RADAR swept around, RF voltages generated on that cable ignited a missile which streaked across the deck, striking an aircraft and blowing its fuel tanks apart. Its two 1000 lb. bombs rolled to the deck and exploded.”

Having a lifelong interest in US Naval aviation history, I decided to use my experience from my service with the Columbia Space Shuttle Accident Investigation Board to revisit the USS Forrestal accident. As I poured through mountains of online and written source material from the Forrestal investigation, it became very evident that an old quote attributed to Mark Twain was applicable – “It ain’t what you know that gets you into trouble. It’s what you know for sure that just ain’t so.”[4] To understand what happened that day, we need to learn fundamental carrier operations from 1967, beginning with the design and operation of the USS Forrestal itself.

The USS Forrestal and Air Operations in Peace Time
The USS Forrestal (CVA-59, Figure 1) was commissioned in 1955 as the lead ship in the Super Carrier class. The US Navy had learned a great deal from trying to operate various jet aircraft from WW2-era Essex-class straight deck aircraft carriers, and realized a major redesign of aircraft carriers for jet operations was required. The Forrestal was thus the first carrier designed exclusively for jet operations.
US Navy Carrier USS Forrestal (CVA-59) with its ship logo (inset)
Figure 1: US Navy Carrier USS Forrestal (CVA-59) with its ship logo (inset) [5]
Watch the deck crews carefully during the launch and landing or recovery operations. Consider all the dangerous tasks that must be completed by the deck crews even under peacetime or training operations. If you served on a carrier deck crew, you knew that injuries and fatalities were commonplace.
The ship was 1,067 ft. in length, 238 ft. in beam, and drafted 37 ft. of water. The ship was a floating city, with a complement of 552 officers, and 4,988 enlisted sailors. It was the first USN carrier with an angled deck (a Royal Navy innovation), four steam catapults, and a radial optical landing system to improve deck landing safety. The Forrestal could carry and perform air operations with 85 jet aircraft of various types. In 1967, these types included the Phantom F4-B, the A-4 Skyhawks, E-2C Hawkeye radar plane, S3-B Vikings, A3 Sky Warriors, and various helicopters. The Forrestal was not nuclear-powered like her later cousins, as its engines were powered by oil-fired boilers. The bunker fuel oil on board had important implications later in the 1967 accident.

When the McDonnel Douglas F-4B Phantom jet became operational with the US Navy in 1963, the USS Forrestal was the first carrier to host an F-4B squadron. If the reader is not familiar with flight operations on a flight deck of this historic era, some important background is required to understand both the complexities and dangers of working around a flight deck. Since print media does not offer a good way to visualize complex carrier operations, I have posted a short US Navy video of the F-4B operations on the USS Forrestal from 1963. To assist in understanding the rest of this article, I strongly suggest watching it to provide context (https://youtu.be/2LDPKwS91s8).[6]

Watch the deck crews carefully during the launch and landing or recovery operations. Consider all the dangerous tasks that must be completed by the deck crews even under peacetime or training operations. There are many inherent flight deck dangers associated with moving jet tugs, steam catapult cables, jet blasts, etc. If you served on a carrier deck crew, you knew that injuries and fatalities were commonplace. Also note that, in this video, none of the aircraft shown have armed and operational weapon systems, although several of the pictured F-4Bs had external fuel tanks.

If you ever encounter a sailor who has served as one of the colored deck shirt crews on a carrier, you would soon learn of the dangers. One sailor interviewed had the following perspective:

“The most dangerous job is having a job on the flight deck. I was a green shirt aboard the USS Nimitz. I have seen an F-18 crash, a helicopter crash, (and) almost got sucked into an F-14 intake, as well as blown across the deck and plenty more close calls. I attribute my attention to detail and situational awareness today to my time spent on the flight deck.”

So, what do those carrier deck shirt colors represent? The Red jerseys were the ordinance and explosive handlers, and disposers. They were also assigned to crash and salvage operations. The White & White‑Checkered jerseys were responsible for aircraft inspections, squadron readiness inspectors, as well as on-deck medical and safety personnel. The Purple jerseys handled everything related to the JP-5 aviation fuel, including fueling, defueling, and fuel integrity. The Brown jerseys were “Plane Captains,” responsible for general maintenance and moving specific aircraft around on deck.

The last three jersey sets had the most dangerous jobs on deck. The Green jerseys were responsible for handling the bridle, executing catapult attachment and, upon landing, detaching the arresting gear. The Blue jerseys were aircraft handlers, elevator operators, as well as tow and start cart drivers. Lastly, the Yellow jerseys (or “mini-air Bosses”) were the plane directors and aircraft handling officers assigned to each of the four catapults. They were the sailors who gave the final command to launch.

Typical Carrier Munitions and Safety Protocols in 1967
While USN jet aircraft were regularly flying with radar-guided Sparrow missiles and infrared-guided Sidewinder missiles in Vietnam, munitions that were used against ground targets in Vietnam were largely iron bombs in the Mark 82/83/84 family. Figure 2 shows the Mark 82/83/84 family, courtesy of the National Museum of the USAF.[7] Normally the USN A-4 Skyhawk and F-4B Phantom jets would carry and drop the Mark 82-84 iron bombs. These weapons were not armed on the deck of a carrier when the aircraft were catapulted. During a strike, after the bomb was released from the aircraft, the spinners shown in Figure 2 (inset) would spin for 10-15 seconds before the weapon was fully armed[8]. This gave plenty of time for the weapon to separate from the aircraft before exploding. Also, if any of the Mark 82-84 weapons were put in direct contact with a deck fire, the casings and internal materials had specifications to survive for up to 5-10 full minutes in direct contact with fire without detonating! This important point will become relevant shortly in the fire’s root cause.
Mark 82/83/84 Vietnam-era iron bombs of yield 500/1,000/2,000 lbs.
Figure 2: Mark 82/83/84 Vietnam-era iron bombs of yield 500/1,000/2,000 lbs. (Courtesy NMUSAF) [7]
On 24 July 1967, the USS Forrestal was spending its first full day on “Yankee Station” 60 miles off the coast of North Vietnam, after having sailed around the world from Norfolk, Virginia. On 25 July 1967, the Forrestal rendezvoused with the US Navy ammunition ship Diamond Head (AE-19) to obtain ordinance for upcoming strikes against North Vietnam. At this time, due to high mission rates against North Vietnam, there was a Pacific theater-wide shortage of Mk83 (1,000 lb.) bombs. Since the MK83s were the weapon of choice for the A-4 Skyhawk, missions would have to be cancelled if the MK83s were not available.

The Diamond Head was a logistics vessel assigned through the US Navy Systems Command, and therefore decided to supply the USS Forrestal with 26 aging Korean War era AN‑M65A1 1000 lbs. bombs[9] (Figure 3) instead of the Mark 83’s. When these 26 bombs were transferred to Forrestal, there was an immediate uproar from the Forrestal’s munition’s safety officer. The munitions squadron was extremely upset about the poor condition of the AN-M65A1 weapons, many of which were rusting, and several were leaking contents. Apparently, the Diamond Head had picked these weapons up from ammo dumps in the Philippine Islands and was supposed to transport them back to the States for disposal. In their poor condition, the Diamond Head likely transferred these weapons to Forrestal to get rid of them.

Korean Era AN-M65A1 1,000 lb. “Thin-Skinned” bomb
Figure 3: Korean Era AN-M65A1 1,000 lb. “Thin-Skinned” bomb[9]
The Forrestal’s weapons officers refused to place these 26 weapons below deck in the armored weapons storage deep within the ship. The officers petitioned Forrestal’s Captain John Belling to immediately throw all 26 weapons overboard. Capt. Belling requested the skipper of the Diamond Head to remove the bombs, but Diamond Head replied that these 26 1,000 lbs. bombs were the only ones available for missions that week. Captain Belling reluctantly directed that all 26 AN-M65A1 bombs were to be stored on the armored flight deck in the “bomb dump” just aft of the carrier’s island. He also ordered strike planners to use these 26 weapons on missions as quickly as possible.

This decision had momentous implications since the AN‑M65A1 were “thinned-skinned” bombs that were not rated to survive direct exposure to fire. Historically, these weapons were known to explode in ~50-80 seconds with direct fire contact, and sometimes faster!

Background on the McDonnel Douglas A-4 Skyhawk and F-4B Phantom Jets
Let’s discuss in more depth two of the most important combat aircraft used for ground attack missions on the USS Forrestal, the A-4 Skyhawk, and the F-4B Phantom. The McDonnel Douglas A-4 Skyhawk was a single-seat ground attack and fighter (see Figure 4). This A-4 is equipped with one 200-gallon JP-5 external fuel tank and 6 each of Mk-1 250 lb. bombs.
McDonnel Douglas A-4 Skyhawk equipped with a 200-gallon JP-5 tanks and 6 Mk81 250 lb. bombs
Figure 4: McDonnel Douglas A-4 Skyhawk equipped with a 200-gallon JP-5 tanks and 6 Mk81 250 lb. bombs [10]

On July 29, 1967, five A-4s scheduled for launch at 1100 that morning were loaded with one 400-gallon JP-5 centerline tank and 2-each of the AN-M65A1 1,000 lb. bombs. Unlike the “shacked” bombs shown in Figure 4, the old Korean era AN-M65A1 bombs were “slung-hung” on the A-4s using specialized canvas straps which were released when the bomb was dropped. These straps were also to play a role later in the day.

On 29 July 1967, the USS Forrestal had planned to launch three different combat strike missions. One mission was to launch at 0700, the second at 1100, and the third at 1500. To get rid of the 26 old AN‑M65A1 bombs, the plan was to send 10 bombs out on five A-4s with the 0700 strike. Ten more bombs would go with the 1100 strike using five A-4s, and the remaining six AN-M65A1 bombs would be used on the 1500 strike using three A-4s. The hope was to get these volatile weapons off the ship by the end of the day on 29 July 1967.

Jet ground start cart on Carrier USS Constellation connected to and starting an A-4 Skyhawk
Figure 5: Jet ground start cart on Carrier USS Constellation connected to and starting an A-4 Skyhawk [11]
The A-4 Skyhawk, like most jets of its era, required a specialized ground cart to start the engines before being launched. Figure 5 shows a typical USN carrier ground start cart connected to an A-4 on the carrier USS Constellation. Generally speaking, it took several minutes to start the engines from the ground start cart. Once the engines were up to speed, the pilots switched over their main power from the ground start to internal aircraft power. Starting an A-4s was therefore a well-known and safe routine.

The F-4B Phantom was a much more complex combat weapon system, capable of carrying a wide range of munitions, and having the ability to fly at sustained supersonic speeds. The F4-B joined the US Navy in 1963, and the “Bedeviler” squadron, seen on the carrier video earlier, was deployed with the USS Forrestal in July of 1967. With its twin turbojets, the F4-B also required a “ground start cart” similar to the A-4 cart shown in Figure 5. Figure 6 shows an Air Force F4 connected to an Air Force version of a ground start cart.

A USAF F4 Phantom with a ground start cart
Figure 6: A USAF F4 Phantom with a ground start cart [12]
To fully understand the root cause of the Forrestal accident, we need to thoroughly explore the procedure to start an F-4B Phantom jet from a ground start cart. Let’s begin by examining the F-4 cockpit controls shown in Figure 7.[13] The F-4B was normally started with the assistance of a ground start cart shown in Figure 5. To protect the F4-B’s own power generating system during startup, the aircraft’s electrical systems were switched over to run on the ground cart’s power. The F-4B cockpit switches to accomplish this are shown on the right in Figure 7. The switches would be placed in the ground start cart EXT position for both the right and left engine power systems. In this position, the pilot would start his engines, one at a time, and make sure they were fully spooled up and wouldn’t flame out.
F-4 showing two power toggle switches used to switch aircraft power from a ground start cart (EXT or LOWER position) to the left or right aircraft engine generator (L Gen/R Gen‑Upper position)
Figure 7: F-4 showing two power toggle switches used to switch aircraft power from a ground start cart (EXT or LOWER position) to the left or right aircraft engine generator (L Gen/R Gen‑Upper position) [13]
Normally during this process, the pilot has his left hand on the two engine throttles shown in Figure 7 on the left side, while his right hand would remain on the switch positions. In order for the pilot to disconnect his aircraft electrically from the ground start cart, he would simultaneously switch the two right switches from the EXT position to the L-Gen/R-Gen position. In doing this, his right hand would NOT be on the control column stick, and his left hand would remain on the engine throttles.

Looking at the actual control column itself, we can also understand the controls necessary toggle one of the many weapon systems installed on the F-4B. Figure 8 shows a close‑up of the control column itself with two of the firing or trigger buttons. Since the F-4 had multiple‑weapon stations for bombs, Zuni rockets, and air‑to‑air missiles, the pilot could select which firing button triggered which weapon though, for the Zuni rockets, the lower buttons were typically‑selected.

F-4 cockpit showing a close-up of the control stick and weapon stations trigger (firing) buttons
Figure 8: F-4 cockpit showing a close-up of the control stick and weapon stations trigger (firing) buttons [14]
The LAL-10 Launcher and Zuni Rocket Subsystems
Next, let’s examine the 5” Zuni rocket system as it was typically installed on USN F-4B’s at the time. Figure 9[15,16] shows an F4-B carrying both iron bombs and four 5” Zuni missile launchers as connected to two LAL-10 weapon stations. These four pictured Zuni tubes could each carry four 5” rockets for a total load-out in this picture of 16 rockets. Each of the unguided Zuni’s carried 125 pounds of high explosive, and were generally used to suppress enemy air defense positions.
(L) An F4-B with two LAL-10 launchers each controlling two 4-tube 5” Zuni rockets (R)
Figure 9: (L) An F4-B with two LAL-10 launchers each controlling two 4-tube 5” Zuni rockets (R) [15,16]
How did ground safety handle these weapon systems to prevent them from going off while the aircraft was on the ground? In the case of the Zuni rocket launchers, the F4-B Zuni launch design was supposed to be impervious to an accidental launch of the Zuni except in the air and in a combat situation. In particular, the USN F4-B weapon system design supposedly required six different interlocks to be closed in order to actually fire any weapon, including the Zuni. Three of those interlocks resided in the cockpit. The pilot had to: 1) select the Zuni weapon station; 2) engage the cockpit weapon master arm switch; and 3) push the appropriate control stick trigger.

The fourth interlock was the landing gear doors. If the gear doors were open, as one would expect on deck, a landing door interlock switch was supposed to prevent launching the weapon if the landing gear doors were open. The last two weapon safety interlocks occurred on the LAL-10 launcher that held the Zuni rockets themselves. These two safety interlocks are shown in Figure 10.

LAL-10 Launcher TER safety pin and friction fit power/control “pigtail”
Figure 10: LAL-10 Launcher TER safety pin and friction fit power/control “pigtail” [17, 18]
On the back end of the LAL-10 launcher was a “TER” safety pin with a red “remove before flight” flag. The TER pin was designed to push an internal LAL-10 switch for both the power and the firing pins into an interrupted or shorted position. In other words, if somehow a firing command had overridden the remaining four interlocks discussed above, this TER pin was supposed to be the safety measure of last resort. This safety pin was supposed to be pulled from the LAL-10 launcher at the catapult, in the seconds before the jet was catapulted into flight.

In addition, the right pigtail friction fit power and firing line connector had to be attached. This pigtail connected the aircraft power and all firing path connections between the F4-B and the LAL-10 launcher. If someone forgot to plug this pigtail in before flight, none of the weapon systems controlled by the LAL-10 would be functional. This connection was also supposed to be done at the catapult, hence the friction-fit nature of the quick disconnect connector. With these six interlock systems in place, the USN Systems Command’s official engineering position was that “it (would be) impossible to accidentally fire a weapon controlled by the LAL-10 on the deck.”

Let’s return for a moment back to the master arm and weapon station interlocks. Again, using the NMUSAF cockpit photograph, the USAF version of the master arm switch is shown in Figure 11. However, the USN’s F4-B master arm and weapons emergency jettison cockpit switches had a slightly different configuration as shown on the far right of Figure 11. Again, during aircraft start-up, the pilot’s hands were on the throttles (left hand) and the external power to generator switches (right hand), and nowhere close to the master arm or jettison switches.

Close-up of the “master arm” weapon station switches in USAF F-4 and USN F4-B
Figure 11: Close-up of the “master arm” weapon station switches in USAF F-4 and USN F4-B [19, 20]
USS Forrestal’s Radar Systems and PLATS Camera Subsystem
Let’s introduce the current on-board high-powered radar systems of the USS Forrestal, shown in Figure 12. The Forrestal’s combat information system was built around the two radars shown. The larger of the two was the AN/SPS-43 long range search radar which operated at 200 MHz, at a peak transmit power of 180 Kilowatts. The antenna pattern was narrow in the azimuth plane, and a broad fan in the elevation plane. Theoretically, it could detect air targets out to 500 km and sea skimming targets to 30 km. The AN/SPS-43 radar was augmented with an S-band SPS-30 height-finding radar, whose function was to get weapons grade range and elevation tracking information for ship self-defense purposes. The SPS-43 would provide a cue to the SPS-30. In addition, the SPS-30 was used during aircraft carrier launch operations to monitor the individual launch velocity of the aircraft being catapulted to ensure the aircraft had sufficient velocity to prevent it from stalling. The SPS-30 velocity information was digitally provided to the pilot landing aid television system (PLATS), which will be discussed shortly.
USS Forrestal’s AN/SPS-43 and SPS-30 radars
Figure 12: USS Forrestal’s AN/SPS-43 and SPS-30 radars [21,22]
As mentioned in the introduction, catapulting and trapping an advanced jet aircraft onto a carrier was considered the most skilled and dangerous flying operation in the entire US military. To ensure every pilot was “on top of their game,” the USN installed the PLATS camera system on the Forrestal in 1963 (see Figure 13). The purpose of the PLATS system was to film (or videotape) every single carrier aircraft launch and landing. Pilots would be graded on how well they executed their takeoffs and especially their landings.
USS Forrestal’s AN/SPS-43 and SPS-30 radars
Figure 13: Pilot landing aid television system (PLATS) camera and operator location on USS Forrestal [23]
When “trapping” or landing, the pilots had to catch one of four arresting cables on deck using their tail hook. A perfect landing was hitting arresting cable #2. If a pilot consistently came in too fast and hit #1 or overshot and hit #4, their proficiency was downgraded. If they couldn’t improve and hit #2 consistently, they lost their carrier pilot certification.

The most important takeaway here is that the PLATS camera was constantly filming every takeoff and landing, and this system would play an outsized role in recording the subsequent accident. To see a typical PLATS video from the USS Forrestal, please visit https://youtu.be/VuCe73IJD7U. Note that the original Forrestal PLATS system recorded the exact time of day to second accuracy and the exit velocity of the launched aircraft from the Ships SPS-30 radar, to ensure the catapult was launching the aircraft well above its specified stall speed.

Wartime Carrier Operational Variations of the USS Forrestal on July 29, 1967
With the essential technical background laid, we now turn our attention to the Forrestal on July 29, 1967. The carrier had been on Yankee station in the Gulf of Tonkin for four days, and the plan for the day was to conduct three separate attack strikes with three groups of the Forrestal’s air complement. Now on a wartime footing, it is clear that the launching and recovery operations had increased in pace, size, and danger. Forrestal had trained extensively for this day, but there were some very notable differences between their training and actual combat operations. For instance, as discussed above, the A-4 and F-4B always started their engines well before their turn on the launch catapult, in order for the engines to be well warmed up and ready for full throttle needed at takeoff. Also, the red shirt weapons technicians were regularly measuring voltage surges on F-4B subsystems at the moment the pilot switched from the ground start carts to their internal 400 Hz aircraft generators.

To avoid any possible “electrical glitch” prior to making the final LAL-10 launcher weapons connections, the approved procedure during training was for the red shirt weapons personnel to make the final weapons pigtail connections and remove the TER safety pins at the catapult just before launch, as shown earlier in Figure 10. If this were done in haste, as frequently happened during the launch of large combat raids, pigtail electrical pins could and were frequently bent, therefore subject to potential shorts in future connections. The real problem, however, was that the Vietnam pilots and their squadron commanding officers complained that making these connections at the catapult significantly slowed down the rate of aircraft launches, and inhibited aircraft recoveries. Connecting all the weapons pig tails could add minutes to each launch depending on the A-4 and F-4B weapons loadout and the size of the strike.

During their transit from Norfolk to the Gulf of Tonkin, the flight deck crews on the Forrestal were briefed by previous Pacific Command carrier weapon handler crews that they had created an ordinance safety “work-around.” In essence, to speed up launches, the red shirt munitions pigtails were to be attached well before arriving at the catapult, and frequently before the aircraft engines had been started. Furthermore, the Forrestal’s red shirts and their munition officer supervisors indicated that this procedure had been approved “by waiver” by previous Pacific Fleet Carrier captains. With this waiver in place, the Forrestal red shirt deck crews were now solely reliant on the “TER safety Pin” that, in theory, was designed to electrically and mechanically prevent a Zuni weapon launch command from the LAL-10 launcher unless the TER pin was pulled. So, the procedure was supposed to be that the red “remove before flight” TER Pins would be pulled at the catapult, while the power and firing line pigtail were already connected.

This is where the first inconsistency of practice took place. While the TER pin was supposed to be pulled out at the catapult, in large combat strikes the TER safety pin was often removed prior to arriving at the catapult. Furthermore, the red jerseys noticed that the TER safety pin had a very loose friction fit. During a launch, the deck winds were typically between 33-39 miles per hour. As related in post-accident witness statements, in several incidences the TER pin was dislodged completely and blown out by the deck winds alone. In the days preceding July 29, 1967, several TER pins and their red flags were seen on Forrestal’s deck during post-launch “Foreign Object Damage“(FOD) sweeps of the flight deck.

Regarding the supposed “safety waiver” mentioned above. It turns out only Captain John Belling could approve such a safety waiver. A former decorated carrier aviator himself, Captain Belling later testified he was never notified of the pre-catapult LAL-10 pigtail connection and early removal of the TER safety pin before the catapult. In the subsequent investigation board, he stated that he would never have approved this new procedure. Reviewing Captain Belling’s many safety messages and “Family Grams” written and read to crew on the voyage from Norfolk to Yankee station, he clearly and consistently emphasized flight deck safety measures even over combat operational efficiency.[24]

It’s now July 29, 1967. The fateful morning of the accident has finally arrived.

References

  1. Leach, R.D., and Alexander, M.B., Editor, NASA Reference Publication 1374 titled Electronic System Failures and Anomalies Attributed to Electromagnetic Interference, Marshall Space Flight Center, July 1995, pp 7, para 2.3.1.
  2. Paul, Clayton R., Introduction to Electromagnetic Compatibility, Wiley, Second Edition, pp 1.3, page 13.
  3. Joffe, Elya B., “Electromagnetic Compatibility (EMC) – an Evolving Discipline from the ‘Garbage of Electronics’ to Global Intersystem Compatibility A Historical Review with Personal Perspectives,” Proceedings of the IEEE International Conference Microwaves, Communications, Antennas and Electronic Systems, COMCAS 2008, May 2008.
  4. Attribution uncertain, but frequently attributed to Mark Twain.
  5. Courtesy USN and National Archives, 31 May, 1962, KN-4507.
  6. You Tube Archive Source. https://youtu.be/2LDPKwS91s8
  7. Photo Courtesy of the National Museum of the United States Air Force (NMUSAF).
  8. Saffold, Ray G., “Safe Arming Times for the Mk 81, 82, 83, 84, and M117 Low Drag Bombs,” United States Naval Ordinance Laboratory Report NOTR-69-135, White Oak, Maryland, 1 August 1969.
  9. Photo Courtesy: https://wiki.warthunder.com/
  10. Photo Courtesy: https://www.historynet.com/arsenal-4-skyhawk
  11. National Geographic History Channel, Single Frame Grab from “Seconds from Disaster Aircraft Carrier Explosion,” Original Broadcast 9-1-2021.
  12. Frame grab from https://www.youtube.com/watch?v=rT_gLtwAjBs
  13. Photo Courtesy NMUSAF
    https://media.defense.gov/2022/Feb/08/2002935433/-1/-1/0/220208-F-AU145-1011.JPG
  14. Photo Courtesy: NMUSAF
    https://media.defense.gov/2022/Feb/08/2002935433/-1/-1/0/220208-F-AU145-1011.JPG
  15. Photo Courtesy: http://www.revuair.com/2017/07/25/we-will-not-forget-3
  16. Photo Courtesy: Pinterest
    https://www.pinterest.com/pin/pinterest–324048135678007426
  17. National Geographic History Channel, Single Frame Grab from “Seconds from Disaster Aircraft Carrier Explosion,” Original Broadcast 9-1-2021.
  18. National Geographic History Channel, Single Frame Grab from “Seconds from Disaster Aircraft Carrier Explosion,” Original Broadcast 9-1-2021.
  19. Photo Courtesy: NMUSAF
    https://media.defense.gov/2022/Feb/08/2002935433/-1/-1/0/220208-F-AU145-1011.JPG
  20. Photo Courtesy: https://navyaviation.tpub.com/14313/css/Armament-Safety-Override-Switch-364.htm
  21. Courtesy USN and National Archives, 12 August 1967, Accession #: 330-CFD-DN-SC-04-09140.
  22. Courtesy Wikipedia – Jon ‘ShakataGaNai’ Davis, https://en.wikipedia.org/wiki/AN/SPS-43#/media/File:SPS-43_radar_of_USS_Hornet_(CVS-12)_2008.jpg
  23. Inset Camera Photo from National Geographic History Channel, Single Frame Grab from “Seconds from Disaster,” Original Broadcast 9-1‑2021, Original from US Navy PLATS Camera.
  24. Killmeyer, Kenneth V., Fire, Fire, Fire on the Flight Deck Aft; This Is Not a Drill, Autherhouse Publishing 2018, Family Grams to Crew from Captain Belling, pp 82-85 and pp 85-88.
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headshot of Brian Kent
Dr. Brian Kent is an engineering consultant and adjunct professor at Michigan State University. His 37-year USAF career included roles as the Chief Technology Officer (AFRL), Chief Scientist (AFRL Sensors Directorate) and Senior Scientist for Low Observable Technology. He supported NASA’s Columbia investigation and Shuttle missions, holds multiple IEEE fellowships, and received a Presidential Rank Award. He’s passionate about naval aviation history. Kent can be reached at brian.kent.phd@gmail.com.
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