Lockheed L-188 Electra
|An L-188A Electra of Pacific Southwest Airlines.|
|National origin||United States|
|First flight||December 6, 1957|
|Primary users||American Airlines
Eastern Air Lines
|Variants||Lockheed P-3 Orion|
The Lockheed L-188 Electra is an American turboprop airliner built by Lockheed. First flying in 1957, it was the first large turboprop airliner produced in the United States. Initial sales were good, but after two fatal crashes which prompted an expensive modification program to fix a design defect, no further orders were placed. The type was soon replaced by turbojet airliners, and many were modified as freighters and the type continues to operate in various roles into the 21st century. The airframe was also used as the basis for the Lockheed P-3 Orion maritime patrol aircraft.
Lockheed had established a strong position in commercial airliner production with its piston-engined Constellation series and was approached by Capital Airlines to develop a turboprop airliner, but with no interest from other American carriers, the company did not produce a design and Capital went on to order 60 British Vickers Viscount four-engined turboprop airliners. In 1954 the company offered a twin-engined design, the CL-303, to meet an American Airlines requirement; it was a high-wing design for 60 to 70 passengers but again the design failed to interest other carriers.
American Airlines then revised its requirement and specified a four-engine design for 75 passengers and a range of 2,000 miles (3,219 km). To meet this Lockheed proposed a new design, the CL-310 with a low wing and either four Rolls-Royce Darts or Napier Elands. The CL-310 design met the American Airlines requirement but Eastern Airlines wanted an aircraft with more range and 85 to 90 seats. Lockheed modified and enlarged the CL-310 design to use the Allison 501-D13, a civilian version of the T56 originally developed for the prototype Lockheed C-130 Hercules military transport.
This design was launched as the Model 188 with an order for 35 aircraft by American Airlines on June 8, 1955, followed by an Eastern Airlines order for 40 on September 27, 1955. The first aircraft took 26 months to complete and by that time Lockheed had orders for 129 aircraft. The prototype, a Model 188A, first flew on December 6, 1957. and was awarded a type certificate by the Federal Aviation Administration (FAA) on 22 August 1958. The first delivery was to Eastern Airlines on October 8, 1958 although it did not enter service until January 1959.
In 1957 the United States Navy issued a requirement for an advanced maritime patrol aircraft. Lockheed proposed a development of the Electra that was later placed into production as the P-3 Orion, which saw much greater success. The Orion approaches nearly 50 years of front-line service.
The Model 188 Electra is a low-wing cantilever monoplane powered by four wing-mounted Allison 501-D13 turboprops. It has a retractable tricycle landing gear and a conventional empennage. It has a cockpit crew of three and can carry 66 to 80 passengers in a mixed-class arrangement, although 98 could be carried in a high-density configuration. The first variant was the Model 188A which was followed by the longer-range Model 188C with increased fuel load and a higher take-off weight.
Operational history 
Civil operations 
American Airlines was the launch customer, followed by Eastern Airlines and Braniff Airways. The Electra suffered a troubled start in service. Passengers of early aircraft complained of high noise levels in the cabin forward of the wings, caused by propeller resonance. To solve this problem, Lockheed redesigned the engine nacelles to tilt the engines upwards by three degrees. The changes were incorporated on the production line by mid-1959 or as modification kits for the aircraft already built, and resulted in much-improved performance as well as increased passenger comfort.
Much worse, three aircraft were lost in fatal accidents in 14 months between February 1959 and March 1960. Following the third crash the FAA restricted the maximum speed at which Electras could be flown until the cause could be determined.
After an extensive investigation, two of the crashes (in September 1959 and March 1960) were found to be caused by an engine mount problem. The mounts were not strong enough to dampen a whirling mode that affected the outboard engine nacelles. When the oscillation was transmitted to the wings, a severe up-and-down vibration escalated until the wings would tear themselves off the aircraft. The company implemented an expensive modification program labelled the Lockheed Electra Achievement Program or LEAP, in which the engine mounts and the wing structures supporting the mounts were strengthened, and some of the wing skins replaced with thicker material. Each of the survivors of the 145 Electras built to that time was modified at Lockheed's expense at the factory, the modifications taking 20 days for each aircraft. The changes were incorporated in subsequent aircraft as they were built. The damage had been done, and the public lost confidence in the type. This and the smaller jets that were being introduced eventually relegated Electras to the smallest airlines. Production ended in 1961 after only 170 aircraft had been built. Losses to Lockheed have been estimated as high as $57 million, not counting an additional $55 million in lawsuits. Although their use continued throughout the 1970s and 1980s for passenger operations, most of the aircraft currently in service are operated as freighters.
Many airlines in the US flew Electras, but the only European airline to order the type was KLM. In the South Pacific, Tasman Empire Airways Limited (TEAL) and its successor Air New Zealand flew the Electra. In Australia Trans Australia Airlines (TAA) and Ansett each operated three Electras on the trunk routes between the Australian mainland state capital cities, and later to Port Moresby, from 1959 until 1971. Ansett had its three Electras converted to freighters in 1970-71 and continued to fly them until 1984. Qantas also operated four Electras on its routes to Hong Kong and Japan; to New Caledonia; and to New Guinea (until the New Guinea route was handed to Ansett and TAA); then later across the Indian Ocean to South Africa, and across the Tasman in competition with TEAL after that airline became 100% New Zealand-owned. The divestiture of TEAL's 50%-Australian shareholding was itself prompted by the Electra order, as TEAL wanted jet aircraft, but was forced by the Australian government to order Electras instead to standardise with Qantas. Three of Qantas' Electras were retired in the mid-1960s and the fourth in 1971.
Some Electras were sold to South American airlines, including Bolivian airline Lloyd Aéreo Boliviano—the Electra allowed Lloyd Aéreo to fly non-stop to international destinations until it took delivery of its first jet airliner—and Varig, operating the Rio de Janeiro-São Paulo shuttle service (the so-called Ponte Aérea - air bridge, in Portuguese) before its Electras were sold to Zaire in 1992. Several secondhand Electras were bought for passenger operations by travel clubs, including Shillelaghs. Others were retired from passenger service into air cargo use, 40 airframes being modified by a subsidiary of Lockheed from 1968 with either one or two large doors in the left side of the fuselage and a reinforced cabin floor.
Military use 
In 1973, the Argentine Navy bought three Electras equipped with cargo doors. These were used during the "Dirty War" to toss political prisoners into the Rio de La Plata, in the infamous death flights. The Electras were also used in transport duties during the Falklands War in 1982.
In 1983, after the retirement of its last SP-2H Neptunes the Argentine Navy bought further civilian Electra airframes, modified several for maritime patrol, and widely used them until their replacement by P-3s in 1994. One of the Argentine Navy's Electras, known locally as L-188W Electron (for electronic warfare), is preserved at the Argentine Naval Aviation Museum (MUAN) at Bahía Blanca.
- Initial production version
- L-188AF (All Freight version)
- Unofficial designation for freighter conversions of L-188A carried out under a supplementary type certificate.
- L-188PF (Passenger-Freight version)
- Unofficial designation for freighter conversions of L-188A carried out under a supplementary type certificate.
- Long-range version with increased fuel capacity (6,940 gallon fuel capacity from 5,450 gallons on L-188A) and a higher operating gross weight (Maximum takeoff weight is 116,000 lb compared to 113,000 lb of the "A" version)
- Unofficial designation for freighter conversion of L-188C carried out under a supplementary type certificate.
- YP-3A Orion
- One Orion aerodynamic test bed, fuselage shortened by seven feet.
Current operators 
As of April 2013, only freighter and firefighting airtankers remained in service, operated by three Canadian companies. Buffalo Airways operated five freighters; another fifteen Electras were registered to Canadian company Air Spray, converted into airtankers with a 3,000 US gallon capacity tank; and two registered to Conair Group, also configured as airtankers.
Civil operators 
Military operators 
- Honduran Air Force - one 188A from 1979
- Mexican Air Force - one 188A from 1978 to 1987.
- Panamanian Air Force - One 188C from 1973 to 1984.
- Model 188A
- Eastern Airlines ordered 40 188As which were delivered between November 1958 and August 1959, the last five as 188Cs.
- American Airlines ordered 35 188As which were delivered between November 1958 and March 1960.
- National Airlines ordered 14 188As which were delivered between April 1959 and January 1961.
- Ansett-ANA ordered three 188As which were delivered to Australia in February 1959, April 1959 and February 1960.
- Braniff ordered nine 188As which were delivered between April 1959 and January 1960.
- Western Airlines ordered 12 188As which were delivered between May 1959 and February 1961.
- Trans Australia Airlines ordered three 188As which were delivered to Australia between June 1959 and August 1960.
- General Motors ordered one 188A which was delivered in July 1958.
- Model 188C
- Northwest Orient Airlines ordered 18 188Cs which were delivered between July 1959 and June 1961.
- Pacific Southwest Airlines ordered three 188Cs which were delivered in November and December 1959.
- Capital Airlines ordered five 188Cs but later cancelled the order, the five aircraft were sold to other operators.
- Qantas ordered four 188Cs which were delivered to Australia between October and December 1959.
- KLM ordered 12 188Cs which were delivered to the Netherlands between September 1959 and December 1960.
- Tasman Empire Airways ordered three 188Cs which were delivered to New Zealand in October and December 1959.
- Garuda ordered three 188Cs which were delivered to Indonesia in January 1961.
Accidents and incidents 
Of the total of 170 Electras built, as of June 2011 58 have been written off because of crashes and other accidents.
- February 3, 1959: American Airlines Flight 320 en route from Chicago to New York City crashed on approach, killing 65 of 73 on board.
- September 29, 1959: A Braniff Electra (Braniff Flight 542) crashed in Buffalo, Texas en route to Dallas, Texas from Houston, Texas. All Twenty-nine passengers and five crew members died in the crash. The Civil Aeronautics Board blamed the crash on the "whirl-mode" prop theory and in-flight separation of a wing from the aircraft.
- March 17, 1960: An Electra operated as Northwest Orient Flight 710, en route from Chicago to Miami, Florida, broke apart in flight over Perry County, Indiana, in the second "whirl-mode" crash. All 63 people on board were killed (57 passengers and six crew members).
- October 4, 1960: Eastern Air Lines Flight 375 crashed on takeoff from Boston, Massachusetts's Logan International Airport, killing 62 of 72 on board. The crash was eventually determined to be the result of bird ingestion in three engines rather than structural failure.
- June 12, 1961: KLM Flight 823 crashed short of the runway at Cairo killing 20 out of the 36 on board.
- September 17, 1961: Northwest Orient Airlines Flight 706 crashed on takeoff from Chicago-O'Hare International Airport, killing all 37 on board. The crash was eventually determined to be the result of mechanical failure in the aileron primary control system due to an improper replacement of the aileron boost assembly.
- April 22, 1966: American Flyers Flight 280 crashed into a hill on approach to Ardmore Municipal Airport in Oklahoma, killing all 5 crew and 78 of the 93 passengers on board.
- February 16, 1967: Garuda Indonesia Airways Flight 708 crashed while attempting to land at Manado-Sam Ratulangi Airport. 22 of 92 passengers and crew on board were killed. The crash was eventually determined to be the result of an awkward landing technique resulting in an excessive rate of sink on touchdown. Marginal weather at the time of landing was a contributing factor.
- May 3, 1968: Braniff Flight 352, which was en route from Houston to Dallas, disintegrated over Dawson, Texas. All 80 passengers and five crew members were killed. This was the worst air disaster in Texas at the time. The Probable Cause found by the National Transportation Safety Board was excessive loads put upon the aircraft structure while attempting to recover from an unusual attitude resulting from loss of control in thunderstorm turbulence; the operation in the turbulence resulted from a decision to penetrate an area of known severe weather.
- August 9, 1970: LANSA Flight 502 crashed shortly after takeoff, killing 99 of the 100 people on board, plus two people on the ground.
- December 24, 1971: LANSA Flight 508, which was en route from Lima to Pucallpa, Peru, entered an area of strong turbulence and lightning and disintegrated in mid air due to structural failure following a lightning strike and fire. Of the 92 people on board, 91 were killed. One passenger, Juliane Koepcke, survived the crash.
- June 4, 1976: An Air Manila 188A (RP-C1061) crashed just after takeoff from the Guam Naval Air Station, killing the 45 occupants and one person on the ground.
- On November 18, 1979, Transamerica Airlines L-188 (N859U), operating a flight for the US military (Logair 3N18) from Hill Air Force Base, crashed near Salt Lake City airport, Utah. While climbing between 12,000 and 13,000 ft, all electrical power was lost; the crew requesting an immediate descent. The aircraft attained a high airspeed and a high rate of descent and the aircraft disintegrated in flight killing all three crew members. The NTSB investigation stated the probable cause was a progressive failure of the aircraft electrical system leading to the disabling or erratic performance of flight critical flight instruments and lighting. As a result the crew became disoriented and lost control of the aircraft. The crew's efforts to regain control of the aircraft imposed loads which exceeded the design limits and caused it to break up in flight.
- On 8 June 1983, Reeve Aleutian Airways Flight 8's propeller separated from the aircraft and tore a hole in the fuselage over the Pacific Ocean causing an explosive decompression and loss of control. The pilots managed to land the aircraft safely at Anchorage, Alaska and all 15 passengers and crew survived. Since the propeller fell into the sea the cause of the separation is undetermined.
- May 30, 1984: Zantop International Airlines Flight 931, a Lockheed L-188AF Electra (N5523) flying regularly scheduled cargo service from Baltimore/Washington International Airport (BWI) to Detroit-Willow Run Airport (YIP), crashed at Chalkhill, Pennsylvania killing all three crew members and the sole, non-revenue, passenger. While cruising at FL220, at approximately 01:44AM, the aircraft entered an unusual attitude shortly after a course change. During efforts to recover the aircraft the pilots imposed loads on the airframe in excess of the aircraft's design limits and the aircraft subsequently broke apart at altitude. NTSB reported that in-flight problems with the aircraft's gyros likely provided conflicting attitude data to the flight crew at the time of the upset and this, combined with a lack of visual cues, were contributing causes of the accident.
- January 21, 1985: Chartered Galaxy Airlines Flight 203 crashed after takeoff from Reno-Cannon International Airport en route to Minneapolis, Minnesota, killing 70 of the 71 people on board.
- December 18, 1995: An overloaded 188C of Trans Service Airlift crashed near Cahungula, Angola with the loss of 141 of the 144 occupants.
Specifications (Model 188A) 
Data from Lockheed Aircraft since 1913
- Crew: Five (3 flight deck)
- Capacity: 98 passengers
- Length: 104 ft 6 in (31.85 m)
- Wingspan: 99 ft 0 in (30.18 m)
- Height: 32 ft 10 in (10.00 m)
- Wing area: 1,300 sq ft (120.8 m²)
- Empty weight: 57,400 lb (26,036 kg)
- Max. takeoff weight: 113,000 lb (51,256 kg)
- Powerplant: 4 × Allison 501-D13 turboprop engines, 3,750 eshp (2,800 kW) each
- Maximum speed: 390 knots (448 mph, 721 km/h) at 12,000 ft (3,660 m)
- Cruise speed: 324 knots (373 mph, 600 km/h)
- Range: 1,913 nmi (2,200 mi, 3,540 km) with maximum payload, 2,409 nmi, 2,770 mi, 4,455 km with 17,500 lb (7,938 kg) payload
- Service ceiling: 32,000 ft (9,753 m)
- Rate of climb: 1,970 ft/min (10 m/s)
See also 
- Lockheed Model 10 Electra, an unrelated piston-engine airliner with the same name
- Related development
- Aircraft of comparable role, configuration and era
- Antonov An-10
- Antonov An-12
- Bristol Britannia
- Canadair CL-44
- Ilyushin Il-18
- Vickers Vanguard
- Vickers Viscount
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- "Accident Synopsis: 09291959." AirDisaster.Com. Retrieved: July 17, 2010.
- Accident description for "The September 29, 1959 accident of Lockheed L-188A Electra N9705C at Buffalo, TX." at the Aviation Safety Network. Retrieved on July 17, 2010.
- Accident description for "The March 17, 1960 accident of Lockheed L-188C Electra N121US at Cannelton, IN." at the Aviation Safety Network. Retrieved on July 17, 2010.
- Accident description for "The October 4, 1960 accident of Lockheed L-188A Electra N5533 at Boston-Logan International Airport, MA (BOS)." at the Aviation Safety Network. Retrieved on July 17, 2010.
- Accident description for "The June 12, 1961 accident of Lockheed L-188C Electra PH-LLM at Cairo International Airport (CAI)." at the Aviation Safety Network. Retrieved on July 17, 2010.
- Accident description for "The September 17, 1961 accident of Lockheed L-188C Electra N137US at Chicago-O'Hare International Airport, IL (ORD)." at the Aviation Safety Network. Retrieved on July 17, 2010.
- Accident description for "The February 16, 1967 accident of Lockheed L-188C Electra PK-GLB at Manado-Sam Ratulangi Airport (MDC)." at the Aviation Safety Network. Retrieved on July 17, 2010.
- Accident description for "The May 3, 1968 accident of Lockheed L-188A Electra N9707C at Dawson, TX." at the Aviation Safety Network. Retrieved on July 16, 2010.
- Accident description for "The August 9, 1970 accident of Lockheed L-188A Electra OB-R-939 at Cuzco Airport (CUZ)." at the Aviation Safety Network. Retrieved on July 17, 2010.
- Accident description for "The December 24, 1971 accident of Lockheed L-188A Electra OB-R-941 at Puerto Inca." at the Aviation Safety Network. Retrieved on July 17, 2010.
- NTSB report # AAR-77-06.
- Accident description for "The June 4, 1976 accident of Lockheed L-188A Electra RP-C1061 at Guam-Agana NAS (NGM)." at the Aviation Safety Network. Retrieved on June 29, 2011.
- Accident description for "The January 21, 1985 accident of Lockheed L-188A Electra N5532 at Reno/Tahoe International Airport, NV (RNO)." at the Aviation Safety Network. Retrieved on July 16, 2010.
- Accident description for "The December 18, 1995 accident of Lockheed L-188C Electra 9Q-CRR at Cahungula." at the Aviation Safety Network. Retrieved on July 17, 2010.
- Francillon 1982, p. 403.
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|Wikimedia Commons has media related to: Lockheed L-188 Electra|
- Information, Pictures and Production List
- Engineering Summary of Propeller Whirl on the Electra
- Kiwanis Electra Memorial website
- NTSB Report on 1968 Braniff N9707C Crash