HALO/HAHO Troop Insertion

Royal Moroccan Special Operations personnel jump from a Boeing CH-47 Chinook at a high altitude during training. (U.S. Army National Guard photo by Spc. Christopher Hall)

What’s one silent way to infiltrate an enemy position? From the sky. That’s the idea behind high-altitude insertion for delivering troops and military equipment. You may be aware of static line jumping, where paratroopers parachute into a military operation from low altitudes, often less than 1,000 feet. But, you know what’s more sneaky? Inserting from as high as 35,000 feet. That’s the purpose of HALO and HAHO jumps.

HALO and HAHO are the two techniques of high-altitude military parachuting, or military free fall (MFF). HALO refers to high altitude-low opening while HAHO refers to high altitude-high opening. In HALO, the jumper, after free-falling all the way down, opens their parachute at an altitude as low as 3,000 feet and plunges to their target. In HAHO, the parachutist opens their chute at a high altitude just a few seconds after exiting the plane and travels to their target along a pre-defined path.

U.S. Marines prepare to conduct a high altitude high opening (HAHO) jump from a CH-53 Super Stallion. (U.S. Marine Corps photo by Cpl. Andre Dakis/Released)

There are typical scenarios for when a HALO or HAHO jump is necessary. Let’s say you’re on the hunt for a fictional infamous terrorist named Caliph Al-Zidane, the leader of a fictional militant group known as the 69th Oppression Army. You’ve found his hideout, and it’s in a major warzone. You rule out a drone strike to minimize casualties. Still, you can’t send troops via helicopter because of the presence of surface-to-air missiles around the area. But, you can task a special operations team to infiltrate a nearby area with a HALO jump and patrol on foot to Al-Zidane’s hideout and eliminate him.

But, what if the airspace around Al-Zidane’s hideout is closed to your military? You don’t want to fly into enemy skies and risk getting shot down, but really want to get that guy. Luckily for you, Al-Zidane’s spot is near the border of a country whose airspace you’re free to patrol. You can fly to that border and have your troops jump out at a high altitude, open their chutes a few seconds after, and travel all the way to an ideal location near Al-Zidane’s hideout. Remember to do it at night because people would likely spot troops inserting via parachute in the day, making your sneaky mission impractical.

U.S. Army soldiers of the 1st Special Forces Group conduct a high altitude low opening jump from a C-130J Super Hercules. (U.S. Air Force photo/Staff Sgt. Jonathan Snyder)

HALO jumps trace their origins back to the 1940s when the United States Air Force (USAF) began conducting experiments on survivability for pilots ejecting at high altitudes. The lead experimenter, Colonel John Stapp, strapped himself to a rocket-powered sled to study the effects of bailing out of aircraft at extreme speeds and find out how to keep pilots safer. Stapp helped develop pressure suits and ejection seats for this purpose.

Building on Stapp’s work, another Air Force Colonel named Joseph Kittinger performed the first high-altitude jump at 102,800 feet, still the record for the world’s highest skydive. How did he get to that height? A hot air balloon. It was a dangerous decision that carried the risk of death, but Kittinger succeeded anyways.

With the viability of high-altitude jumps already proven and major improvements along the way, the HALO technique was put to work by the American MACV-SOG special operations unit active in the Vietnam war. In 1971, they HALOed into an area to gather intel about a new road the North Vietnamese Army was building from Cambodia.

MACV-SOG special operations perform a HALO jump during pioneering tests in 1970.

Building on previous work, a British Army soldier named Charles Bruce was pivotal in conducting original trials of the HAHO tactic. HAHO allows a longer travel distance of more than 40 miles due to increased time under the parachute canopy. Today, HALO/HAHO combat jumps are mostly performed by special operations teams. Originating in the U.S. and the U.K, the technique has been passed down to many other militaries across the globe.

High-altitude military parachuting is one of the most physically demanding and dangerous skills in military operations. People who intend to participate must pass through rigorous training with strict rules and regulations. The training often begins with learning how to stabilize the body in a specially-made vertical wind tunnel.

All parachuting techniques are risky, but HALO and HAHO carry more risks due to the operation at high altitudes. At heights greater than 22,000 feet, lack of oxygen is a danger for jumpers, so they need to wear oxygen masks and carry an oxygen task. Also, rapid ascent in the jump aircraft without flushing nitrogen from the bloodstream can lead to decompression sickness. Hence, there’s a pre-breathing period (30-45 minutes) where the jumper breathes 100% oxygen to flush out nitrogen from their bloodstream.

U.S. Navy SEALs conduct High Altitude Low Opening (HALO) airborne operations in an exercise in Alaska. (U.S. Army photo by Sgt. Stefan English)

HALO/HAHO jumps have been used in many combat missions in this decade. In 2012, two dozen U.S. Navy SEALs parachuted from a C-130 Hercules military transport aircraft to rescue two American hostages, Jessica Buchanan and Poul Hagen Thisted, in a Somali town and recovered them successfully after killing all nine kidnappers. More recently, in 2020, U.S. Navy SEALs also parachuted into an area in Northern Nigeria and successfully rescued an American hostage, killing six of the seven captors.

HALO jumps aren’t exclusively for military operations. Superstar actor Tom Cruise performed a real-life HALO jump in the United Arab Emirates when shooting the blockbuster 2018 movie Mission: Impossible – Fallout.