ANC13LA067

The pilot had been cleared to land long on the runway as requested, but, because he became aware of a faster airplane that would be landing behind his airplane, he decided to land closer to the approach end so that he could exit the runway about midfield instead. The pilot reported that the new landing location resulted in an encounter with turbulence and a left crosswind from the lingering jet blast from a Boeing 747 that departed from an adjacent runway. The airplane veered sharply right during the wheel landing and ground-looped. The air traffic controller had included a "caution jet blast" advisory in the pilot's landing clearance, and Federal Aviation Administration guidance states that pilots conducting operations under visual flight rules are expected to adjust the flightpath, as necessary, to avoid wake encounters.

On July 23, 2013, about 2000 Alaska daylight time, a Cessna 180A tailwheel-equipped airplane, N4814, veered right and ground-looped during landing at the Ted Stevens Anchorage International Airport (ANC), Anchorage, Alaska. The commercial pilot was not injured, and the airplane sustained substantial damage. The personal flight was operated under the provisions of 14 Code of Federal Regulations Part 91 with no flight plan filed. Visual meteorological conditions prevailed. The flight departed from Scooter's Landing Strip Airport (AK84), Sterling, Alaska, about 1930. The pilot stated that the ANC tower controller cleared his flight to land on runway 7L and approved his request to land long on the 10,600-foot runway. He stated that he typically landed the airplane on the last 2,000 to 3,000 feet of the runway so that he could exit near the end. He stated that this time, he was mindful of a Beech 1900 airplane that would be landing behind his airplane, so he planned to land and exit about midfield instead. The pilot stated that, during the approach and while his airplane was about 50 feet above the ground, his airplane encountered a "jet blast" from a Boeing 747 that had departed from runway 33 (which intersects runway 7L near the approach end). The pilot stated that the jet blast included a crosswind from the left and felt "like light to moderate turbulence" with "two distinct bumps." The pilot stated that his airplane made it through the jet blast and that he performed a wheel landing about 75 miles per hour. Shortly thereafter, the airplane veered sharply to the right and ground-looped. The airplane sustained damage to the left main landing gear, fuselage, both wings, left aileron, and left elevator. The pilot reported no known mechanical malfunctions what would have precluded normal operation of the airplane. The pilot stated that the landing clearance that the ANC tower controller provided to him included a "caution, jet blast" advisory. The pilot stated that he believed that the light quartering tailwind present at the time of his landing enabled the jet blast winds from the Boeing 747 to drift eastward into the runway environment. Chapter 7, Section 3 of the Federal Aviation Administration (FAA) Aeronautical Information Manual provides guidance to pilots of light aircraft regarding wake turbulence, which includes jet engine blast and wake vortices. The chapter describes vortex behavior and provides guidance for avoiding wake turbulence encounters. Section 7-3-1 notes that jet engine blast can cause damage and upsets if encountered at close range, and section 7-3-4 notes that, because wake vortices are the by-product of wing lift, the vortices are generated the moment that the departing transport category aircraft leaves the ground (after the point of rotation). Section 7-3-6 notes that, for pilots operating under visual flight rules, "WHETHER OR NOT A WARNING OR INFORMATION HAS BEEN GIVEN [by an air traffic controller]…, THE PILOT IS EXPECTEDTO ADJUST AIRCRAFT OPERATIONS AND FLIGHT PATH AS NECESSARY TO PRECLUDE SERIOUS WAKE ENCOUNTERS" (capitalization emphasis in original document)." The pilot was involved in a previous ground-loop accident in the airplane on May 23, 2006. In that accident, the airplane bounced during landing in crosswind conditions and veered to the right, sustaining substantial damage.