F Company 2nd Battalion, 135th General Support Aviation Battalion (formerly A Company, 5th Battalion, 159th Aviation Regiment (1996-2008) & B Company 1st Battalion, 214th General Support Aviation Battalion (2008-2016)), conducts high-altitude search-and-rescue operations. Based at Joint Base Lewis-McChord's Gray Army Airfield, the Army Reserve aviation unit transports National Park Service emergency search-and-rescue teams to and from the mountain. The company inherited the SAR mission in July 1998, when the active-Army unit tasked with the responsibility was inactivated. During regular training sessions before and during the climbing season, the unit's CH-47 Chinook helicopters fly to Kautz Creek near the base of the mountain to pick up the SAR teams. Then the combined group performs insertion and extraction drills at locations from roughly 10,000 feet to the summit at 14,410 feet above sea level. SAR missions are varied. F Company participated in a search for a missing snowboarder on the southeast side of the mountain. Hampered by foul weather and heavy cloud cover, the mission extended into several days as Chinook pilots and crew-members transported SAR teams and flew search patterns, working routes, crevasses and tree lines where the snow-boarder might be. The victim never was found. Another mission involved two climbers who lost vital equipment during a climb on the Liberty Ridge ice face, at 13,000 feet. They requested help by cell phone, but the first Chinook sortie was turned away by an intense squall line, requiring additional flights to drop off and later pick up rescue teams.