higher interceptor speeds. The F-94s replaced most of the Twin Mustangs of the 449th FIS at Ladd, however about a dozen F-82s (of various types) were retained due to their longer flight endurance and their ground support capability that the F-94 lacked. Army ground units in Alaska were very limited in their movements due to the geography of the land. Most movements were up and down roads and paths and railroad rights-of-way. The F-82s would fly low along the terrain then pop up and initiate simulated strafing runs against them, causing the troops to take cover by hitting the muddy tundra. On occasions, the Twin Mustangs would also drop tear gas canisters, simulating gas attacks on the units. The F-82s, however, had no logistical support available and were maintained by cannibalization of un-flyable aircraft, with the last few replacement aircraft coming from Japan when Far East Air Forces sent some lower-hour airframes to Ladd after being withdrawn from Korean War combat and weather reconnaissance operations. The ones received from FEAF, however, were in a badly corroded condition and required much effort to keep them operational. About 100 F-94A and B models arrived at Ladd, enough to equip all three interceptor squadrons. Of the 10 remaining Twin Mustangs, only one or two were operational at any one time. Another useful use of the Twin Mustangs was their ability to perform reconnaissance along the Siberian border and monitor Soviet use of former Lend-Lease auxiliary airfields near the coast. Eventually the lack of logistical support for the F-82 made them simply unserviceable, the last Twin Mustang being grounded in October 1953 and was dropped from the inventory rolls. The F-86H Sabre-equipped 720th Fighter-Bomber Squadron was activated in December 1953 to evaluate the use of the Sabre as an interceptor. However, it was determined that the same mission could be performed by rotating existing Tactical Air Command squadrons from the CONUS to Alaska instead. The 21st Fighter-Bomber Wing, based at George AFB, California began two-week rotational TDY F-86 deployments to Eielson AFB until November 1954 when it was reassigned to France. Air Defense Command F-89C Scorpions, replacing the F-94s, began to be received in September 1953. They were initially assigned to the 65th FIS. Two more F-89 squadrons, the 18th and 433d, were assigned to Ladd in 1954. The F-89s were an improvement of the Starfires, and functioned well in the extreme arctic conditions