When in the early 1950s the Lockheed company was approached by Capital Airlines to develop an airliner powered by propeller-turbine engines, it declined citing a lack of interest in such a project from other airlines. Capital instead turned to the British company, Vickers, and placed an order for 60 Viscounts. In late 1954, American Airlines responded by issuing a specification for a 70-seat short haul turboprop-powered airliner. Lockheed’s initial proposal was a twin-engine, high wing design but American changed the specification to a larger, four-engine aircraft capable of carrying 75 passengers 2,000 miles and turning a profit when also operating shorter distance flights. Lockheed’s revised response was the CL-310, with a choice of either Rolls-Royce Dart or Napier Eland engines. The emergence of an Eastern Air Lines requirement for an aircraft to carry 85 passengers over even greater distances led to the adoption of the Allison 501D engine, a civil version of the T56A installed on Lockheed’s Hercules military transport. Both American and Eastern placed firm orders in 1955 and, by the time of the first flight, Lockheed was in posession of contracts for 129 aircraft.
The Electra entered service on 12 January 1959. However, on 3 February, pilot error led to the crash of an American Electra on approach to La Guardia with the loss of 65 lives. On 29 September, 34 people were killed when a Braniff Electra broke up in mid-air, and a further 63 died when a Northwest example also broke up in flight on 17 March 1960. The cause of the two mid-air break-ups was traced to weaknesses in the engine mountings which result in wing flexing and catastrophic failure of the wing root. Lockheed introduced an upgrade package to resolve the problem but public confidence in the Electra had been lost. Cruise speed restrictions imposed by the FAA led many airlines to look more closely at jets, not least as United Air Lines had by this time placed an order for Caravelles. Lockheed decided to terminate the programme (a decision likely made a little easier by the United States Navy’s adoption of the Electra as the basis for a new land-based anti-submarine patrol aircraft), and the last aircraft made its first flight before the cruise speed restrictions were lifted. American Airlines, one of the launch customers began to dispose of its Electras the following year.
Despite its somewhat shaky start, the Electra remained in passenger service until the late 1990s. Between them, specialist operators Conair, Air Spray and Buffalo Airways have acquired a large number of Electras for conversion to firefighting tankers and as sources of parts for their respective active fleets. Although Conair has now retired its Electras, operations by the other two companies continue, with Air Spray planning at least one more tanker conversion.
First flight: 6 Dec 57 (c/n 1001, N1881)
Production: 170, at Burbank, CA
First delivery: 8 Oct 58, to Eastern Air Lines (c/n 1007, N5502)
Last delivery: 23 Jun 61 (c/n 1144, N138US)
Variants: 188A - initial production version powered by 4 Allison 501D-13, -13A or -15 tubroprops, with seating for up to 98 passengers (115 built); 188B - unofficial Lockheed designation for 188C c/ns 2001-2022 intended for export and equipped with track mounted seats, additional lavatories and a navigator station; 188C - 188A with increased fuel capacity and higher operating weights (55 built).
Conversions: Air Spray, Buffalo Airways and Conair have all completed conversions of a number of Electras for use as retardant aerial delivery tankers. The Argentine Navy converted a handful of Electras for electronic warfare and electronic intelligence gathering duties, using systems provided by Israel.