Boeing CH-47 Chinook the CH-47 have been developed since the helicopter entered service. The U.S. Army's first major design leap was the now-common CH-47D, which entered service in 1982. Improvements from the CH-47C included upgraded engines, composite rotor blades, a redesigned cockpit to reduce pilot workload, improved and redundant electrical systems, an advanced flight control system, and improved avionics. The latest mainstream generation is the CH-47F, which features several major upgrades to reduce maintenance, digitized flight controls, and is powered by two 4,733-horsepower Honeywell engines. A commercial model of the Chinook, the Boeing-Vertol Model 234, is used worldwide for logging, construction, fighting forest
San Francisco and Oakland Helicopter Airlines San Francisco and Oakland Helicopter Airlines San Francisco and Oakland Helicopter Airlines (also known as SFO Helicopter Airlines and SFO Helicopter) was a helicopter airline service offering scheduled passenger flights between San Francisco, Oakland, and other Bay Area cities. It was founded in 1961 but disappeared from the Official Airline Guide 15 years later before finally going out of business in 1986. San Francisco and Oakland Helicopter Airlines was one of the first helicopter airlines to operate without a federal subsidy and it was also the first to operate with only turbine engine helicopters. Since helicopter landing sites were scarce