Air America was one of the largest operators of twin beeches in the world during the sixties and early seventies with over 30 aircraft. 

The majority of aircraft acquired were C-45. Twelve were converted to “Ten-Two” configuration in 1963/4. This increased the maximum take-off weight to 10,200Ib (Ten-Two) to achieve this improvement the power plant was modified, the stabilizer incidence was increase, new gear doors were installed, and aerodynamically improved wing tips were added. 

Additionally 14 aircraft were converted to Volpar Turbo Beeches following from 1966, which involved the conversion to tricycle landing gear configuration and the install of two Garrett TPE-331-47 turbo-prop engines along with other airframe improvements. This conversion increased the maximum take-off weight to 10,286Ib and increased the airspeed to 245 mph. Another bonus of this conversion was the elimination of the nose over tendency to nose over under heavy braking. (there are so many images of air America beech 18s on there back or with broken noses from nose overs) 

Brief Air America History of N9956Z 

• Acquired by Air America in Sept./Oct. 1965 but financed and owned by The Pacific Corporation.
• Based out of Saigon starting 27th Oct. 1965.
• Ferried to Tainan for repairs of damage sustained from ground fire. Nov. 1965.
• Officially bought by Air America Mar. 1966.
• Sustained dame to fuselage roof, engines, and propellers after flipping over during landing at Saigon. Aug. 1966.
• Converted to Volpar Turbo Beech by Air Asia Aug. 1966 to Jan. 1967.
• Based out of Saigon from June 1967
• PC-6 N152L was blown into N9956Z by wind while parked at Tan Son Nhut airport. Repaired Aug. 1968
• Based out of Tainan late 1974.
• Ferried to Roswell NM July 1975 to Aug. 1975.
• Sold to Omni Aircraft Sales Nov. 1975.
• Deregistered Nov. 1976. and sold to CIBA-Pilatus Aerial Spraying as HB-GGI Jan. 1977.
• Registration was cancelled Jan. 1980. and aircraft was broken up at Tucson Intl. Airport Oct. 1980.