Lockheed L-188 Electra

L-188 Electra
An Electra freighter of NWT Air at Vancouver Airport in August 1983.
Role	Short-medium-range transport
National origin	United States
Manufacturer	Lockheed
First flight	1957
Introduction	1958
Primary users	American Airlines Eastern Air Lines Braniff Airways KLM Pacific Southwest Airlines
Produced	1957–61
Number built	170
Variants	P-3 Orion

The Lockheed L-188 Electra is an American turboprop airliner built by Lockheed. It was the first turboprop airliner produced in the United States. It first flew in 1957 and when first delivered had only slightly inferior performance to that of a turbojet airliner but at a lower operating cost.

Design and development

The design of the Electra was started by Lockheed in 1954, and the following year the company received a launch order from American Airlines. The prototype first flew on December 6, 1957. The aircraft is a low-wing monoplane with retractable tricycle landing gear, powered by four Allison 501D-13 turboprops. Standard accommodation was for 66 to 88 passengers, with an optional high-density layout for 98 passengers. The initial production version was the L-188A. Later a longer-range L-188C was produced. A total of 170 aircraft were built, with production stopped earlier than planned due to the lack of confidence in the design after two fatal crashes. The aircraft were modified following the accidents but by then customers were interested in operating turbojets. Most of the aircraft currently in service are operated as freighters. In 1957 the United States Navy issued a requirement for an advanced patrol aircraft. Lockheed proposed a development of the Electra which was later placed into production as the P-3 Orion.

Operational history

Civil operations

L188C Electra of KLM Royal Dutch Airlines operating a passenger service in July 1965

American Airlines was the launch customer, followed by Eastern Airlines and Braniff Airways. Many airlines in the US flew Electras, but the only European airline to order the type was KLM. In the South Pacific, TEAL and Air New Zealand flew the Electra. In Australia TAA and Ansett operated Electras on routes between Melbourne, Sydney and Brisbane, and to Port Moresby from 1959 until 1971. Qantas also operated four Electras, VH-ECA,B,C & D at about the same time across the Tasman. The Electras flew in commercial service until the mid-1970s. Some units were sold to Brazilian airline Varig, operated with a perfect safety record until 1992 on the Rio de Janeiro-São Paulo (that route is called Ponte Aérea - air bridge, in Portuguese) shuttle service before being sold to Zaire. Others were retired into air cargo use. A total of 144 L-188s were built, 57 of which have been destroyed in accidents, according to the Aviation Safety Network^[1]. The most recent Electra accident was in July 2003.

Military use

In 1973 the Argentine Navy bought three Electra equipped with cargo door. These were used by the military dictatorship to toss political prisoners (the disappeared) into the Rio de La Plata, in the infamous Death flights ^[2].

In 1983, after the retirement of their last SP-2H Neptunes the Navy bought further civilian Electras airframes and modified several for maritime patrol ^[3], and widely used them until their replacement by P-3s in 1994 ^[4]. 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 Bahia Blanca.

Variants

An L-188CF of Atlantic Airlines.

L-188A

Initial production version

L-188AF (All Freight version) and L-188PF (Passenger-Freight version)

Freighter conversions of L-188A

L-188C

Long-range version with increased fuel capacity (6940 gallon fuel capacity from 5450 gallons on L-188A) and a higher operating gross weight ( Maximum takeoff weight is 116000lb compared to 113000lb of the "a" version)

After Lockheed's modifications for the whirl mode fix, "ElectraII" and "Super Electra" were names attached to the Electra.

L-188CF

Freighter conversion of L-188C

YP-3A Orion

One Orion aerodynamic test bed, fuselage shortened by seven feet.

CP-140 Aurora and CP-140A Arcturus uses P-3 Orion airframe

Operators

Accidents and incidents

• On February 3, 1959, American Airlines Flight 320 en route from Chicago to New York City crashed on approach, killing 65 of 73 on board. This crash pushed the deaths of Buddy Holly, The Big Bopper, and Ritchie Valens (also in a plane crash) off the front pages.

• On September 29, 1959, a Braniff Electra (Braniff Flight 542) crashed in Buffalo, Texas en route to Dallas, Texas from Houston, Texas. 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 plane.^[6]

• Just under six months later, on 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 crashing in a farm field eight miles east of Cannelton. All 63 people on board were killed (57 passengers and six crew members).

These last two, in-flight, accidents mirrored each other and shocked the aviation industry. The FAA Administrator requested Lockheed Aircraft Corporation to reevaluate the Electra. NASA and Lockheed engineers eventually determined that the engine mounts---following the failure of an engine mount during a hard landing---allowed too much precessional movement of the propellers at a critical frequency which allowed "whirl-mode" aeroelastic phenomenon, "flutter" in flight. This flutter, by pure chance, occurred at the wings' natural resonance frequency, which further excited the harmonic oscillations, which increased the wing flutter, that eventually led to separation of a wing from the fuselage. The engine mounts were redesigned and the wing stiffened so the problem was solved by 1961.

• On 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.

• On 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 NTSB 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.

• On 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 Köpcke, survived the crash.

• On June 4, 1976, an Air Manila Lockheed L-188 Electra L-188A (RP-C1061) crashed just after takeoff from the Guam Naval Air Station. NTSB report # AAR-77-06

• On January 21, 1985 chartered Galaxy Airlines Flight 203 crashed after takeoff from Reno-Cannon International Airport en-route to Minneapolis, Minnesota with 71 people aboard.

Specifications

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General characteristics

• Crew: Six (3 flight deck)
• Capacity: 99 to 127 passengers
• Length: 104 ft 6 inches (31.81 m)
• Wingspan: 99 ft (30.18 m)
• Height: 32 ft 10 inches (10 m)
• Wing area: 1300 sq ft (120.8 m2)
• Empty weight: 61,500 lb (27,895 kg)
• Useful load: 22,825 lb (10,350 kg)
• Max takeoff weight: 116,000 lb (52,664 kg)
• Powerplant: 4× Allison 501-D13 turboprop engines, 3,750 shp (2,800 kW) each

Performance

• Cruise speed: 362 knots (405 mph, 652 km/h)
• Service ceiling: 28,400 ft (9,500 m)

See also

• Lockheed L-10 Electra, an unrelated piston-engine airliner with the same name
  

Related development

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

Comparable aircraft

• Bristol Britannia
• Ilyushin Il-18
• Vickers Vanguard
• Vickers Viscount
  

References

External links

Wikimedia Commons has media related to: Lockheed L-188 Electra

• Information, Pictures and Production List
• ASN Report on 1960 Northwest Orient N121US crash
• ASN Report on 1959 Braniff N9705C crash
• Engineering Summary of Propeller Whirl on the Electra
• Kiwanis Electra Memorial website
• NTSB Report on 1968 Braniff N9707C Crash
• Alternate view on 1968 Braniff N9707C Crash