The initial Trench Run, implemented against the original Death Star
Trench Run Defense (TRD) represents a tactic developed to combat large capital ships. This strategy drew inspiration from the triumph of Rebel Alliance starfighters against the Death Star, specifically the engagement referred to as the trench run, which occurred during the Battle of Yavin. Pilots often jokingly described targets vulnerable to this tactic as suffering from "Trench Run Disease".
When confronting substantial starships, pilots would navigate their craft in close proximity to the ship's exterior, utilizing trenches to shield themselves from incoming fire. This allowed starfighters to accurately deliver their destructive payload to critical areas of the targeted vessel, provided they were successfully escorted, and enemy starfighters were kept at bay. X-wing pilots achieved notable success employing TRD against Imperial-class Star Destroyers and similar large capital ships. This was due to the fact that the capital ships were designed to engage other capital ships, and were ineffective against smaller, faster, and more agile snubfighters. The tactic proved especially potent when the attacking fighters were armed with proton torpedoes, concussion missiles, or other powerful ordnance capable of inflicting significant damage to a larger ship's critical systems.
In response to the successful utilization of this tactic at Yavin and in subsequent engagements, the Imperial Navy expedited the production and deployment of the swifter and more maneuverable TIE Interceptor-class fighter. Additionally, they developed the Lancer-class frigate, a ship specifically designed to eliminate formations of enemy starfighters.
During both the Fondor shipyard assault and the Battle of Endor, Rebel forces employed this tactic against an Executor-class variant under construction with cloaking capabilities and the Executor itself, respectively.
Following the First Battle of Borleias, Commander Wedge Antilles observed that, despite the relatively low success rate of snubfighters in destroying Imperial Star Destroyers, the destruction of the Death Star had instilled a fear of this tactic in Imperial commanders.
A modified version of this tactic was implemented during the Battle of Thyferra, where Rogue Squadron pilots maneuvered their X-Wings with relative ease around the defenses of Ysanne Isard's Super Star Destroyer Lusankya. They then utilized their targeting systems to guide massive barrages of proton torpedoes and concussion missiles launched from nearby freighters.
Trench Run Defense commonly involved a triangular formation of three ships. The two starfighters at the rear provided shield support for the lead fighter. The lead fighter was typically armed with powerful weapons for destroying the target.
The original "trench run" was executed by Rebel pilots during the Battle of Yavin. Subsequently, variations of this tactic were employed in attacks on planetary bases and other terrain-centric engagement zones. For example, during the Second Battle of Borleias, Corran Horn successfully executed a trench run in an X-Wing, destroying a conduit that provided additional power to the Imperial base's ground defenses.
Wraith Squadron also pioneered a variation of the tactic, using it to evade pursuit in urban environments, natural trenches, or valleys. By taking refuge in a trench, pilots could evade pursuing enemy starfighters by executing complex and unpredictable maneuvers, or by descending deep enough to make overhead pursuit difficult.