Transamerica Lockheed L-188 Electra airplane model. The design of the Lockheed L-188 Electra began in 1954, and in the following year the company received a launching order for the airplane from American Airlines. The prototype was first flown on December 6, 1957. Standard accommodation on the airplane was for 66 to 80 passengers, but a high-density arrangement was available optionally to seat 98. A total of 170 airplanes had been built when production ended unexpectedly early as a result of passenger loss of confidence in the aircraft after two had disintegrated in flight, and by the time remedial modifications had been incorporated customer airlines were interested in turbojet rather than turboprop aircraft. About half of the total airplanes built remained in service in the early 1990s, many of them converted by Lockheed Aircraft Service for convertible passenger/cargo or all-cargo use. The L-188A was powered by four 3,750-shp Allison 501D-13 or 501D-13A turboprops, optionally four 4,050-shp 501D-15 turboprops, giving the airplane a maximum cruising speed of 405 mph, service ceiling of 28,400 feet, and a range of 2,200 miles.