Lockheed L-188 Electra

L-188 Electra
An L-188A Electra of Pacific Southwest Airlines.
Role	Turboprop airliner
National origin	United States
Manufacturer	Lockheed Corporation
First flight	December 6, 1957
Introduction	1959
Status	In limited use[1]
Primary users	American Airlines Eastern Air Lines Braniff Airways National Airlines
Produced	1957–61
Number built	170
Variants	Lockheed P-3 Orion

The Lockheed L-188 Electra is an American turboprop airliner built by Lockheed. First flown in 1957, it was the first large turboprop airliner built in the United States. Initial sales were good, but after two fatal crashes that led to expensive modifications to fix a design defect, no more were ordered. However, with its unique, high power-to-weight ratio, huge propellers and very short wings (resulting in the majority of the wingspan being enveloped in propwash), large Fowler flaps which significantly increased effective wing area when extended, and four-engined design, the airplane had airfield performance capabilities unmatched by many jet transport aircraft even today—particularly on short runways and high field elevations. Turboprops were soon replaced by turbojets and many Electras were modified as freighters. Some Electras are still being used in various roles into the 21st century.^[1][2] The airframe was also used as the basis for the Lockheed P-3 Orion maritime patrol aircraft.

Development

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 proceed and Capital went on to order 60 British Vickers Viscounts.^[3] In 1954 the company offered the twin-engined 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.^[3]

American Airlines then revised its requirement to a four-engined design for 75 passengers with 2,000 miles (3,219 km) range.^[3] Lockheed proposed a new design, the CL-310 with a low wing and four Rolls-Royce Darts or Napier Elands.^[3] The CL-310 design met the American Airlines requirement but Eastern Airlines wanted more range and 85 to 90 seats.^[3] Lockheed enlarged the CL-310 design to use the Allison 501-D13, a civilian version of the T56 developed for the Lockheed C-130 Hercules military transport.^[3]

This design was launched as the Model 188 with an order for 35 by American Airlines on June 8, 1955, followed by an Eastern Airlines order for 40 on September 27, 1955.^[3] The first aircraft took 26 months to complete and by that time Lockheed had orders for 129. The prototype, a Model 188A, first flew on December 6, 1957^[4][5] 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 but it did not enter service until January 1959.^[3]

L188C Electra of KLM Royal Dutch Airlines operating a passenger service at Manchester Airport in 1963

An L-188CF of Atlantic Airlines

An Electra freighter of NWT Air at Vancouver Airport in August 1983

Lockheed L-188 Electra of TAN Airlines (Transportes Aéreos Nacionales S.A.) operating at Las Mercedes Airport, Managua, Nicaragua in 1970

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.

Design

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 tail. 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 layout. The first variant was the Model 188A, followed by the longer-range 188C with room for 1000 gallons more fuel and maximum take-off weight 3000 lb higher.

Operational history

Civilian operations

American Airlines was the launch customer. Eastern Airlines, Braniff Airways and Northwest Airlines followed. The Electra suffered a troubled start. Passengers of early aircraft complained of noise in the cabin forward of the wings, caused by propeller resonance.^[6] Lockheed redesigned the engine nacelles, tilting the engines upwards three degrees.^[6][7] The changes were incorporated on the production line by mid-1959 or as modification kits for the aircraft already built, and resulted in improved performance and a better ride for passengers.^[7][8]

Three aircraft were lost in fatal accidents between February 1959 and March 1960. After the third crash the FAA limited the Electra's speed until the cause could be determined.^[6]

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 damp a phenomenon called "whirl mode flutter" (analogous to the precession of a child's top as it slows down) that affected the outboard engine nacelles. When the oscillation was transmitted to the wings and the flutter frequency decreased to a point where it was resonant with the outer wing panels (at the same frequency, or harmonically related ones), violent up-and-down oscillation increased until the wings would tear themselves off.^[6][9][10] The company implemented an expensive modification program (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.^[6] All Electras were modified at Lockheed's expense at the factory, the modifications taking 20 days for each aircraft. The changes were incorporated in later aircraft as built.^[6] 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 170 had been built. Losses to Lockheed have been estimated as high as $57 million, not counting an additional $55 million in lawsuits.^[5] They continued to carry passengers into the 1980s, but most Electras now in use are freighters.

Many airlines in the US flew Electras, but the only European airline to order the type from Lockheed was KLM which used twelve between September 1959 and January 1969 in Europe and east to Saigon and Kuala Lumpur.

In the South Pacific, Tasman Empire Airways Limited (TEAL) and its successor Air New Zealand flew the Electra.^[11] 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.^[8] Ansett had its three Electras converted to freighters in 1970-71 and continued to fly them until 1984.^[12] 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.^[11][13] 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 to standardise with Qantas.^[13][14][15] Three Qantas Electras were retired in the mid-1960s and the fourth in 1971.^[11]

Some Electras were sold to South American airlines, where, contrary to what had happened in the U.S., the Electra had highly successful operations, such as those of Lloyd Aéreo Boliviano and Líneas Aéreas Paraguayas;^[16] in both cases, the Electra ensured the airlines' international operations before they started using jets. Most notably, Varig from Brazil operated the Electra on the extremely busy Rio de Janeiro-São Paulo shuttle service (the so-called Ponte Aérea - "Air Bridge," in Portuguese) flawlessly for many years before the type was replaced by Boeing 737-300 and Fokker 100 jets in 1992, and mostly sold to then Zaïre the following year.^[17] The Electra became so iconic on that route that its retirement caused a commotion in Brazil, with extensive press coverage and many special tributes.^[18]

During the mid-1970s, several secondhand Electras were bought by travel clubs, including Adventurers and Shillelaghs. Others were retired from passenger service into air cargo use, 40 being modified by a subsidiary of Lockheed from 1968 with one or two large doors in the left side of the fuselage and a reinforced cabin floor.^[6] Air California and Pacific Southwest Airlines were still operating Electras for passenger service during the late 1970s into smaller airports in the western United States.

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.^[19] The Electras were also used in transport duties during the Falklands War in 1982.

In 1983, after the retirement of its last SP-2H Neptune, the Argentine Navy bought further civilian Electra airframes, modified several for maritime patrol,^[20] and widely used them until their replacement by P-3s in 1994.^[21] 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.

Variants

L-188A

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.

L-188C

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)

L-188CF

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.

Operators

Current operators

As of January 2014, only freighter and firefighting airtankers remained in service, operated by three Canadian companies. Buffalo Airways operates five freighters and one air tanker;^[22] another fourteen Electras were registered to Canadian company Air Spray, converted into airtankers with a 3,000 US gallon capacity tank;^[1][23] and one^[24] or two^[25] registered to Conair Group, also configured as airtankers.^[24]

Former civilian operators

Military operators

 Argentina

• Argentine Naval Aviation

 Bolivia

• Bolivian Air Force

 Ecuador

• TAME

 Honduras

• Honduran Air Force - one 188A from 1979

 Mexico

• Mexican Air Force - one 188A from 1978 to 1987.

 Panama

• Panamanian Air Force - One 188C from 1973 to 1984.

Orders

Model 188A

• Eastern Airlines ordered 40 188As which were delivered between November 1958 and August 1959, the last five as 188Cs.^[30]
• American Airlines ordered 35 188As which were delivered between November 1958 and March 1960.^[30]
• National Airlines ordered 14 188As which were delivered between April 1959 and January 1961.^[30]
• Ansett-ANA ordered three 188As which were delivered to Australia in February 1959, April 1959 and February 1960.^[11][30]
• Braniff ordered nine 188As which were delivered between April 1959 and January 1960.^[30]
• Western Airlines ordered 12 188As which were delivered between May 1959 and February 1961.^[30]
• Trans Australia Airlines ordered three 188As which were delivered to Australia between June 1959 and August 1960.^[30]
• General Motors ordered one 188A which was delivered in July 1958.^[30]

Model 188C

• Northwest Orient Airlines ordered 18 188Cs which were delivered between July 1959 and June 1961.^[30]
• Pacific Southwest Airlines ordered three 188Cs which were delivered in November and December 1959.^[30]
• Capital Airlines ordered five 188Cs but later cancelled the order, the five aircraft were sold to other operators.^[30]
• Qantas ordered four 188Cs which were delivered to Australia between October and December 1959.^[30]
• KLM ordered 12 188Cs which were delivered to the Netherlands between September 1959 and December 1960.^[30]
• Tasman Empire Airways ordered three 188Cs which were delivered to New Zealand in October and December 1959.^[30]
• Garuda ordered three 188Cs which were delivered to Indonesia in January 1961.^[30]

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.^[31]

• February 3, 1959: American Airlines Flight 320 en route from Chicago to New York City crashed on approach, killing 65 of 73 on board.^[32][33]
• September 29, 1959: A Braniff Electra (Braniff Flight 542) crashed in Buffalo, Texas en route to Dallas, Texas from Houston, Texas. All 29 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.^[34][35]
• March 17, 1960: 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).^[6][36]
• September 14, 1960: An Electra operated as American Airlines Flight 361 caught its landing gear on a dike while landing at LaGuardia Airport. The aircraft came to rest upside down. There were no fatalities amongst the 76 occupants (70 passengers, six crew).^[37][38]
• 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 into three of the four engines.^[39]
• June 12, 1961: KLM Flight 823 crashed short of the runway at Cairo killing 20 of the 36 on board.^[40]
• 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 the improper replacement of the aileron boost assembly.^[41]
• March 27, 1965: While on a training flight, a Tasman Empire Airways L-188 crashed while landing at Whenuapai airport in Auckland, New Zealand. Although the aircraft was completely destroyed, all occupants escaped with only one minor injury.^[42]
• April 22, 1966: American Flyers Flight 280 crashed into a hill on approach to Ardmore Municipal Airport in Oklahoma, killing all five 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. A total of 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.^[43]
• May 3, 1968: Braniff Flight 352, 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 airframe resulting from loss of control in thunderstorm turbulence.^[44]
• August 9, 1970: LANSA Flight 502 crashed shortly after takeoff, killing 99 of the 100 people on board, plus two people on the ground. The co-pilot was the only survivor.^[45]
• December 24, 1971: LANSA Flight 508, en route from Lima to Pucallpa, Peru, entered an area of strong turbulence and lightning and disintegrated in midair due to structural failure following a lightning strike and fire. Of the 92 people on board, 91 were killed.^[46] 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.^[47][48]
• 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 requested 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 passenger. While cruising at FL220, at approximately 01:44 AM, the aircraft entered an unusual attitude shortly after a course change. During efforts to recover the aircraft the pilots imposed loads on the airframe that exceeded the aircraft's design limits and it 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.^[49]
• December 18, 1995: An overloaded 188C of Trans Service Airlift crashed near Cahungula, Angola with the loss of 141 of the 144 occupants.^[50]

Specifications (Model 188A)

Data from Lockheed Aircraft since 1913^[51]

General characteristics

• Crew: Five (3 flight deck)
• Capacity: 98 passengers
• Payload: 33,800 lb (7938 kg)
• 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

Performance

• 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

• Lockheed P-3 Orion
• Lockheed CP-140 Aurora
• Lockheed P-7

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

References

Notes

Bibliography

Further reading

• Nuñez Padin, Jorge (2006). Lockheed L-188 Electra. Serie Aeronaval (in Spanish and with English abstract) Nº20. Retrieved May 6, 2014. 

External links

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
• "Lockheed Electra" a 1955 Flight article