Terrain - following flying Terrain - following flying referred to a tactic in which starfighters or combat airspeeders would fly at altitudes that were perilously close to the surface of a planet , moon , or other celestial body . Often used to defy detection from varying types of sensors while " en route " to or making a run in on a target , requiring superior situational awareness and reflexes in order to avoid crashing . Characteristics . This type of piloting was particularly dangerous to both machine and being as the tactic was at its most effective when executed through unstable , unpredictable terrain , such as that of mountain ranges , cityscapes , asteroids , or the most famous instance of terrain - following flying , the trench run phase of the Battle of Yavin . Due to the nature of most types of sensors used throughout the galaxy , flying in such close proximity to the surface of a world essentially scrambled their readings ; instead of detecting a starfighter executing the tactic , they would simply return a readout of the ground itself . This was a particular flaw of so - called " line - of - sight " forms of detection . Similar tactics included the Horizon Approach and Hull skimming . History . The tactic of flying extremely close to the surface of a world to avoid detection was , perhaps , as old as the concept of flying itself , long before the age of space warfare and interplanetary conquest . The most famous instances of terrain - following flying were practiced by the starfighters of the Rebel Alliance and later the New Republic Defense Force , though they were by no means the only practitioners . Those who were the victims of this tactic soon learned to adopt it themselves ; such flying was best - suited for small - scale raids against outlying targets or those with a minimum of air - or space - based defenses or those that were inadequate for defending against starfighters . During the Battle of Yavin , Gold and Red Squadrons used terrain - following flying as they attempted to exploit a weakness in the design of the original Death Star . Flying through an equatorial trench that ringed the surface of the vast battlemoon , they attempted to elude the Galactic Empire ' s TIE / LN starfighter s as well as the guns on the surface ; though the trench itself was also lined with turbolaser emplacements , they were too heavy and slow to effectively target the smaller X - and Y - wings of the Rebels . However , Darth Vader and his wingmates were able to do the same thing , downing two successive attempts by the Alliance forces to fire their proton torpedoes into the thermal exhaust port at the end of the trench . However , Luke Skywalker , utilizing his newfound powers in the Force , was able to succeed in destroying the battle station . Following the victory at Yavin , the Rebels continued to utilize the tactic , adapting it for runs against Imperial capital ships in what came to be known as the Trench Run Defense . The heavy firepower of the Star Destroyers that made up the bulk of the heavy units within the Imperial Navy were largely ineffective against fast - moving Rebel craft , a weakness that was exploited at the Battle of Endor against a number of " Imperial " - class Star Destroyers as well as the Star Dreadnought " Executor " . Flying through the canyons that lined the surface of the massive , nineteen - kilometer long vessel , a number of X - wings and A - wing s were able to strike at the warship ' s command tower , whose bridge deflector shields had been brought down by an earlier attack pass . An A - wing flown by Arvel Crynyd dealt the final blow , smashing into the bridge and sending the ship plunging into the second Death Star . The tactic continued to be used throughout the subsequent years of the Galactic Civil War , including the Defense of Vladet and the Assault on Borleias two years later , as well as the Adumari Civil War in 13 ABY .