Home / Articles / Low-Tech, High-Reward: The Houthi Drone Attack
A recent drone attack in Yemen hasn’t received much attention outside the small circle of experts that pay attention to the conflict in Yemen or the proliferation of unmanned aerial vehicles (UAV or drones), but it will likely be a historical footnote in the proliferation of unmanned technology to sub-state militants.
On January 10, a weaponized unmanned aerial vehicle exploded above a number of senior officers, killing at least 6 members of the Saudi-backed Yemeni forces gathered at an army parade near the al-Anad airbase, just outside the Saudi- and Emirate-controlled port city of Aden.
Imagery of the attack and drone wreckage suggests the vehicle in question was an Iranian Ababil-T from the Ababil II family of drones. Iran is a documented supplier of weapons to the Houthi movement and has used the Ababil drone, redubbed “Qasef-1,” in at least 12 attacks throughout the country.
In the short term, the attack is likely to increase tensions and could result in the Saudi-backed coalition renewing plans to oust the Houthi-allied force from Hodeidah, a key port on the Red Sea, as part of a broader effort to place the north under siege. The attack is also certain to undermine a fragile ceasefire, intended to halt fighting in Hodeidah and to arrange for the transfer of authority over the port city to mutually agreed on administrators. The civil war remains at a stalemate, with the civilian population bearing the brunt of the fighting. According to the United Nations, 14 million people are at risk of starvation, and up to 85,000 children may have already died of hunger.
Beyond the human suffering, the drone attack underscores how insurgents are now routinely using low-tech, off-the-shelf tools to conduct autonomous attacks that challenge technologically superior states. The use of cheap drones for armed attack is a growing trend in the region’s myriad of conflicts, dating back to Hezbollah’s use of unmanned vehicles in 2006, and continuing in Syria, Turkey, Iraq, and Yemen. The trend shows how non-state actors are developing relatively accurate, stand-off weapons capable of precision strikes far from insurgent strongholds. The attacks are more a military nuisance for the defenders, but it demonstrates a clever use of low-cost technologies to conduct asymmetric attacks on expensive equipment and can kill small numbers of soldiers.
In that sense, the attack is reminiscent of an earlier incident involving an explosive-armed Iranian drone: Israel’s 2006 war with Lebanon. At the outset of the air war, Israeli planners tasked F-15 and F-16 aircraft to fly combat air patrols off the Lebanese coast to track and engage any Hezbollah-operated Ababil drones.
Imagery of drone wreckage from 2006 and reporting at the time suggested that Hezbollah used an Iranian Ababil-T, the same drone model that was used in the most recent Yemen attack. The underlying technology in both drones—from 2006 and then in 2019—appears to be the same. However, over the past 13 years, the Houthis have access to more open source satellite imagery, which has allowed them to identify targets, and then been able to use the war-time conditions in Yemen to further experiment and innovate. The result is the Houthis are using drones in ways reminiscent of precision-guided-munitions, over far greater distances than other insurgent groups in the Middle East.
The Qasef-1 provides the operator with a number of advantages over the off-the-shelf drones that have proliferated widely in Iraq and that the Islamic State used to harass Operation Inherent Resolve troops in Mosul and Syria. However, ISIS drones were primarily hobby quadrotors of the DJI phantom variety that have on average 20 minutes of flight time and can carry only smaller, 40mm grenade-sized payloads. By contrast, the Qasef offers users a greater range. For example, the Qasef used in a May 2018 attack on Abha Regional Airport inside Saudi Arabia was around 100 km from the Saudi border—a range that ISIS or other groups have not yet demonstrated.
That’s not to say that the Ababil-T is a technological wonder. It has decades-old technology derived from target drones designed to be used for target practice. It’s cheap, easy to manufacture, easily transportable, and requires relatively little supporting logistics to operate. A quick look at the United Nations Panel of Experts on Yemen January 2018 report shows that much of the technology is commercially derived from global suppliers.
The internal electronics, according to the Panel of Experts, are sourced from local Iranian suppliers and electronic suppliers based mostly in Asia. The Qasef-1 uses GPS for guidance, flying autonomously along pre-programmed waypoints, and has a range of up to 150 km when carrying a 30-45kg warhead. After reaching the pre-programmed GPS coordinates, the Qasef’s power switches off, and the drone glides to the target. Depending on the atmospheric conditions at the target, the Qasef is reported to strike within 25 meters of its intended target.
The two Qasef-1s now on display at the Iranian Materiel Display at Joint Base Anacostia clearly shows that this is not the first use of a weaponized drone. According to Emirati officials that Conflict Armament Research interviewed for the report, “Iranian Technology Transfers to Yemen,”
Houthi and Saleh-aligned forces employ the Qasef-1 to target Coalition MIM-104 ‘Patriot’ surface-to-air missile systems. They do so by crashing the UAVs into the systems’ radar sets (specifically the circular main phased arrays)—directing the UAVs by programming their systems with open-source GPS coordinates of the Patriots’ positions.
Many have speculated about the warhead used in the parade attack. Despite the recovery of a number of Qasef drones by Saudi-led coalition forces, little is known about either the warheads or fuses they employ. Nonetheless, it may be reasonable to infer that an air bursting anti-personnel warhead of some kind was employed based on precedent. In the May 2018 airport attack, Saudi authorities recovered ball bearings, which suggest an anti-personnel role rather than the “crash and smash” methods reportedly used against air defense radars.
The Houthis have leveraged low-technology to befuddle a technologically superior ally. The near-term impact of the January 10 attack could be a return to conflict in Hodeidah—an outcome that would worsen the famine and lead to more innocents suffering. For the United States, the longer-term implications are linked to the creative ways low-tech adversaries are using drones to their advantage. The war in Yemen, as my colleague and friend Adam Rawnsley often says, is a preview of what a larger American-Iranian conflict could look like. Iranian-backed forces have a history of using cheap unmanned aircraft to its advantage. Yemen is the latest case study, and history suggests that countering these threats costs more than it does to launch them.
*The author is indebted to Adam Rawnsley, who shared his insights, and offered useful comments on an earlier draft. Any errors are, of course, mine alone.