Direct proof of use
Conflict Armament Research documented Qasef-1 UAVs in the 2014 Yemen Civil War and reported that Houthi and Saleh-aligned forces used them to disable Saudi-led coalition Patriot missile-defense systems in Yemen. CAR described the attack method as crashing the UAVs into Patriot radar sets, especially the circular main phased arrays, after programming the aircraft with open-source GPS coordinates for the Patriot positions.
CAR's 2017 field report tied the operational claim to physical evidence: a Qasef-1 recovered near Aden International Airport on 16 November 2016, six partially assembled Qasef-1 UAVs intercepted in Marib Governorate on 27 November 2016, and a damaged engine from a UAV used in a Marib attack in October 2016. The same report said the Qasef-1 displayed by Houthi forces on 26 February 2017 matched the UAVs CAR had documented.
Sources: Iranian Technology Transfers to Yemen, Evolution of UAVs Employed by Houthi Forces in Yemen
Timeline
The earliest directly described incident in CAR's public reporting is the October 2016 Marib attack, where CAR later documented a damaged Qasef-1 engine. On 16 November 2016, Presidential Guard forces recovered a Qasef-1 that reportedly crash-landed near Aden International Airport, and on 27 November 2016 they intercepted six partially assembled Qasef-1 UAVs in Marib Governorate.
The public identification of the type followed in February 2017, when Houthi forces displayed four UAVs and called one of them Qasef-1. CAR's later evolution report said it had documented eight Qasef-1s and one Qasef-1 engine seized in Yemen between October 2016 and July 2018, distinguishing seven industrially manufactured examples from a hybrid example documented in July 2018.
Sources: Iranian Technology Transfers to Yemen, Evolution of UAVs Employed by Houthi Forces in Yemen
Role in the conflict
The Qasef-1's documented role in Yemen was suppression and degradation of coalition missile-defense infrastructure. CAR reported that Houthi and Saleh-aligned forces used the UAVs against coalition MIM-104 Patriot surface-to-air missile systems so follow-on missile volleys could threaten coalition assets with the Patriot radar disabled. Defense News, summarizing the CAR findings in March 2017, likewise reported that rebels were flying the drones into Saudi-led coalition Patriot radar sets.
The use claim is separate from the transfer and manufacture question. CAR assessed that the Qasef-1 was not an indigenous Yemeni design and placed it in the Iranian Ababil-II family, while DVIDS reported a December 2017 U.S. Defense Department display of a Qasef-1 recovered by Saudi Arabia and described it as a Houthi-operated one-way attack drone. Those sources support provenance and recovery context, while the conflict-use claim rests most directly on CAR's Yemen field documentation.
Later reporting treated the Qasef-1 as the first-generation Houthi combat UAV in a line that included modified or locally assembled examples and the closely related Qasef-2K. USIP summarized the Qasef family as used in kamikaze-style Houthi attacks and cited CAR's finding that Qasef-1s were used in 2017 against Saudi missile-defense systems.
Sources: Iranian Technology Transfers to Yemen, Evolution of UAVs Employed by Houthi Forces in Yemen, Report: Houthi Rebels Flying Iranian-Made Kamikaze Drones, DoD Shows Iranian Weapons as Proof of Tehran's Duplicitous Ambitions, Iran's Drone Transfers to Proxies
