used more often as a training aircraft. The FAA performed a series of flight tests on the Twin Comanche and NASA conducted wind tunnel tests and found no unusual tendency to spin beyond what would normally be expected given the airflow of the normally rotating propellers. In the 1970s, the FAA changed its training standards and required flight instructors to obtain a separate rating to teach in multiengine aircraft. The Vmc accidents dissipated dramatically. In 1997, the Aircraft Owners and Pilots Association (AOPA) Air Safety Institute published a safety review of the Comanche series aircraft and concluded that the Twin Comanche showed no greater tendency for Vmc roll-over spins than comparable aircraft. Kristin Winter, a long time Twin Comanche instructor, operator, and trained accident investigator, reviewed the NTSB records for a ten-year period ending in 2014 and concluded that the Air Safety Institute's report was correct in its conclusions. Of the six single engine loss of control accidents, most resulted from inexperienced pilots and substandard training. Prince William of Gloucester bought a Twin Comanche and used it as his personal aircraft for several years in the 1960s. He flew it from the United Kingdom to Nigeria, where he held a diplomatic post; then later returned in it to the United Kingdom and flew it to Japan when he took up a diplomatic post in that country. A Twin Comanche was flown in the 1992 and 1994 French Arc en Ciel air races. It is the only US aircraft to have raced twice around the world. In the pilot-skilled races, 1992 pilot and Pioneer Hall of Fame enshrinee and 100 Aviation Hero for the First Century of Flight, Marion P. Jayne and her daughter Nancy Palozola placed second. In 1994 Jayne and her daughter, Patricia Jayne (Pat) Keefer won the FAI Gold Medal in what, so far, is the longest race in history at over 21,000 miles flown May 1–24, 1994. With FAA approval the twin carried a total of 252 gallons in 11 tanks and at maximum power went over 2,100 miles nonstop between Marrakech, Morocco and Istanbul, Turkey in 11:19 hours. All Twin Comanche engines have long times between overhaul (2000 hours for the B1A, 1800 for the IO-320-C1A) and have developed a reputation for reliability. Following a string of accidents involving pilot loss-of-control in single-engine flight (due to engine failure, or in pilot training for engine-failure conditions), Piper