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Yakovlev Yak-42

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Yakovlev Yak-42
Company typeAircraft model
IndustryAerospace
Founded1970s
FounderYakovlev design bureau
ProductsTri-engine passenger jet airliner


Template:Infobox aircraft

The Yakovlev Yak-42 (Russian: Яковлев Як-42; NATO reporting name: "Clobber") is a tri-engine passenger jet designed in the mid-1970s to accommodate between 100 and 120 passengers on medium-range routes. It was introduced as a successor to the aging Tupolev Tu-134 and marked the Soviet Union's first airliner equipped with advanced high-bypass turbofan engines.

Development

File:Volga-Aviaexpress Yak-42 tail.jpg
Rear perspective highlighting the tri-turbofan exhausts and the lowered rear airstair.

In 1972, the Yakovlev design bureau initiated development of a short- to medium-haul airliner intended to transport 100–120 travelers. The aircraft aimed to replace not only the jet-powered Tupolev Tu-134 but also turboprop models such as the Ilyushin Il-18, Antonov An-24, and Antonov An-26. Although the new model needed to operate efficiently from relatively small airports, it was not required to perform on unpaved runways like the smaller Yakovlev Yak-40, given that many Soviet airfields had been modernized for more sophisticated aircraft. This led to the creation of Yakovlev's largest, heaviest, and most powerful airplane to date.

Early concepts featured a straight-wing design powered by two Soloviev D-30 turbofan engines, resembling an enlarged version of the Yak-40. This approach was ultimately dismissed because it was deemed less competitive against Western aircraft employing high bypass ratio turbofans. Consequently, Yakovlev adopted a configuration with three new Lotarev D-36 three-shaft high-bypass turbofans, each delivering approximately 63.90 kN (14,330 lbf) of thrust. Unlike its predecessor, this airliner incorporated swept wings.

The initial prototype, bearing registration SSSR-1974 and equipped with an 11-degree wing sweep, completed its first flight on 7 March 1975. It was succeeded by a second prototype, SSSR-1975, which featured a 23-degree wing sweep and expanded cabin windows arranged in 20 rows instead of the original 17. The third prototype, SSSR-1976, introduced enhanced anti-icing systems.

Design

File:Yakovlev Yak-42D Cockpit.jpg
flight deck operated by two crew members

The Yak-42 is an all-metal, low-wing monoplane engineered to endure 30,000 flight cycles of one hour each.[1] Its fuselage features a circular cross-section and is pressurized, accommodating up to 120 passengers in a six-abreast seating configuration, or alternatively 100 passengers for shorter routes where additional space is allocated for carry-on baggage and coat storage. The cockpit is manned by a duo of pilots. Passenger boarding is facilitated by two airstairs: one located beneath the rear fuselage similar to the Yak-40, and another positioned forward on the port side of the cabin. Beneath the passenger compartment, there are two cargo holds designated for luggage, freight, and mail.[2]

File:Yak-42D (5453983163).jpg
The Yak-42 features a low swept wing

Early prototypes were equipped with main landing gear consisting of two wheels per leg; however, production models introduced four wheels on each main gear.[3] The wing design underwent significant modifications during development: the initial prototype had an 11-degree wing sweep, whereas the second prototype increased this to 23 degrees. Following assessments, the greater sweep angle was adopted for series production. Initial models featured a clean leading wing edge without control surfaces and simple trailing-edge flaps. Subsequent versions incorporated leading edge slats and slotted trailing-edge flaps.[1][2][4]

The propulsion system includes two engines mounted in pods on either side of the aft fuselage and a third engine housed within the rear fuselage that receives air via an "S-duct" intake. An auxiliary power unit (APU) is also installed in the aft fuselage section. The aircraft lacks thrust reversers. It features a T-tail configuration with both vertical stabilizer and horizontal tailplanes exhibiting sweep.[2]

Operational history

File:Aeroflot Yakovlev Yak-42 Gilliand.jpg
Aeroflot Yak-42 displayed at the 1981 Paris Air Show

The first production Yak-42 was finalized on 28 April 1978, with its inaugural scheduled passenger service operated by Aeroflot on the Moscow-Krasnodar route commencing on 22 December 1980. Early production progressed slowly, with only ten aircraft completed by mid-1981. Initial cabin layouts provided seating for 120 passengers in a three-by-three arrangement. This was soon revised to include a first-class section arranged two-by-two alongside a main cabin accommodating 96 seats, resulting in a total capacity of 104 seats.[5][6]

During its debut year in service, Aeroflot's Yak-42 fleet transported approximately 200,000 passengers predominantly on Moscow-based routes but also internationally between Leningrad and Helsinki, as well as from Donetsk to Prague. Plans were made to expand its deployment across Aeroflot's operations.[7] However, on 28 June 1982, an Aeroflot Yak-42 experienced catastrophic tailplane separation due to failure of the actuator screw jack, resulting in a fatal crash near Mazyr. This incident led to grounding of the type until October 1984.[8]

In 1982, an export contract for seven units was announced by Aviogenex of Yugoslavia, though this agreement ultimately did not materialize.[6] The introduction of the extended-range Yak-42D model from 1991 facilitated several export sales to countries including Bosnia, China, Cuba, and Iran.[9] By 1 January 1995, production had reached a total of 185 Yak-42 aircraft manufactured worldwide, comprising 105 units of the Yak-42D variant.[10]

Variants

File:Yakovlev Yak-42D, S-Air JP6370740.jpg
Interior of a business aircraft
Yak-42

The initial production model with a maximum takeoff weight of 54,000 kg (119,050 lb).[11]

Yak-42ML

Equipped with upgraded avionics tailored for international operations (mezhdunarodnyye linii – international routes). This variant began service in July 1981 on the Leningrad-Helsinki route.[8]

Yak-42D

A long-range model (Dal'niy – long distance) featuring increased fuel capacity. It succeeded the standard Yak-42 in production.[9]

Yak-142

An evolution of the Yak-42D incorporating modern western AlliedSignal avionics, aerodynamic spoilers to enable steeper descents, and an enlarged cabin door compatible with jet bridge boarding. Also known under the designations Yak-42A, Yak-42-100, and Yak-42D-100.[12]

Yak-42R

A test platform variant for radar development related to the Yakovlev Yak-141 fighter aircraft.[10]

Yak-42F

Modified Yak-42 adapted for geophysical and environmental surveys, equipped with large underwing pods housing electro-optical sensors.[13]

Yak-42LL

A testbed converted to evaluate the Progress D-236 propfan engine. This configuration featured a single D-236 engine (rated at 8,090 kW / 10,850 shp) mounted on a specially designed pylon replacing the starboard engine to provide adequate clearance for its 4.2 m (13 ft 9¾ in) diameter propellers. Its maiden flight occurred on 15 March 1991.[10]

Yak-42M

A proposed extended version of the airliner that was never built. It was intended to have three Progress D-436 turbofan engines, an elongated fuselage, and redesigned wings. This concept later evolved into the Yak-242.[14]

Yak-242

An advanced development of the Yak-42M featuring two underwing Aviadvigatel PS-90 turbofan engines. This design ultimately progressed into the Irkut MC-21.[15]

Operators

By July 2019, there were still 22 Yak-42 aircraft actively operated by commercial airlines. The current operators included Izhavia with eight aircraft, KrasAvia operating ten, and Turukhan Airlines with four.[16]Template:Needs update

Accidents and incidents

Up to 15 February 2018, the Yak-42 had been involved in eight fatal crashes and one non-fatal event, resulting in a total of 570 fatalities.

28 June 1982
Aeroflot Flight 8641, operating a Yak-42 (registration CCCP-42529), lost control after a horizontal stabilizer jackscrew failure caused by fatigue from design flaws. The aircraft entered an uncontrolled dive, disintegrated mid-air, and crashed near Verbovichi in the Naroulia District, Byelorussian Soviet Socialist Republic, killing all 132 occupants. Following this accident, all Yak-42s were grounded until corrective measures were implemented in October 1984. This remains both the deadliest accident involving a Yak-42 and the worst aviation disaster in Belarus to date.[17]
September 1986
During security forces training exercises involving an Aeroflot Yak-42 (CCCP-42536), a thunderflash grenade ignited the cabin interior causing the aircraft to burn out completely; however, no injuries occurred.[18]
14 September 1990
Aeroflot Flight 8175, flying a Yak-42 (CCCP-42351), crashed short of the runway at Koltsovo Airport, Sverdlovsk Oblast due to intentional deviation from approach procedures by the pilot. The collision with trees resulted in four fatalities among the 129 passengers and crew onboard.[19][20]
31 July 1992
China General Aviation Flight 7552, a Yak-42D (B-2755), failed to become airborne during takeoff from Nanjing Dajiaochang Airport, China, overrunning the runway and resulting in the deaths of 108 out of the 126 onboard. Investigation revealed that the horizontal stabilizer was incorrectly trimmed for landing.[21]
20 November 1993
Avioimpex Flight 110, operating a leased Yak-42D (RA-42390) from Saravia, impacted Mount Trojani near Ohrid in North Macedonia due to pilot error. All 116 passengers and crew perished. Macedonian authorities attributed the crash to an inoperative VOR beacon combined with pilot mistakes, while Russian officials suggested communication misunderstandings stemming from language differences between air traffic control and crew transmissions. This remains North Macedonia's deadliest aviation accident.[22]
17 December 1997
Aerosvit Flight 241, flying a Yak-42 (UR-42334) leased from Lviv Airlines, crashed into Mount Pente Pigadia within Greece's Pierian Mountains. Pilot error coupled with cockpit confusion led to all seventy onboard losing their lives.[23]
25 December 1999
Cubana de Aviación Flight 310, operating a Yak-42D (CU-T1285), collided with San Luis hill during approach near Bejuma, Cuba after descending from 8,000 ft (2,400 m) to 4,000 ft (1,200 m) following a prolonged holding pattern of forty minutes. All twenty-two occupants died.[24]
26 May 2003
UM Airlines Flight 4230, a Yak-42D (UR-42352), crashed into mountainous terrain near Maçka in Trabzon Province, Turkey under poor visibility conditions caused by pilot error. All seventy-five onboard perished. The flight was carrying sixty-two Spanish soldiers returning from their deployment with the International Security Assistance Force (ISAF) mission in Afghanistan.[25]
7 September 2011
In the Lokomotiv Yaroslavl plane crash, a YAK-Service Yak-42D (RA-42434) stalled shortly after departing from Tunoshna Airport near Yaroslavl, Russia due to pilot error. Of forty-five people onboard, only one mechanic survived. Among those killed were twenty-nine members of the Kontinental Hockey League team Lokomotiv Yaroslavl.[26]

Specifications (Yak-42D)

File:Yakovlev Yak-42 3-view line drawing.gif
three-view illustration

Template:Aircraft specs

See also

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References

  1. ↑ 1.0 1.1 Gunston and Gordon 1997, p. 195.
  2. ↑ 2.0 2.1 2.2 Taylor 1982, p. 241.
  3. ↑ OKB Yakovlev: A History of the Design Bureau and Its Aircraft von Yefim Gordon (Author), Dmitriy Komissarov (Author), Sergey Komissarov (Author) ISBN 1-85780-203-9 ISBN 978-1-85780-203-0
  4. ↑ Gordon, Komissarov and Komissarov 2005, pp. 312–314.
  5. ↑ Gordon, Komissarov and Komissarov 2005, pp. 314–315.
  6. ↑ 6.0 6.1 Gunston and Gordon 1997, p. 197.
  7. ↑ Flight International 30 January 1982, p. 208.
  8. ↑ 8.0 8.1 Gordon, Komissarov and Komissarov 2005, p. 315.
  9. ↑ 9.0 9.1 Gordon, Komissarov and Komissarov 2005, p. 316.
  10. ↑ 10.0 10.1 10.2 Gunston and Gordon 1997, p. 198.
  11. ↑ Cite error: Invalid <ref> tag; no text was provided for refs named Brasseys 99 p227-8
  12. ↑ Gordon, Komissarov and Komissarov 2005, pp. 317–318.
  13. ↑ Gordon, Komissarov and Komissarov 2005, p. 318.
  14. ↑ Gordon, Komissarov and Komissarov 2005, pp. 319–320.
  15. ↑ Gordon, Komissarov and Komissarov 2005, pp. 320–321.
  16. ↑ Thisdell and Seymour Flight International 30 July–5 August 2019, p. 47.
  17. ↑ Template:ASN accident
  18. ↑ Template:ASN accident
  19. ↑ Lua error in Module:Citation/CS1/Configuration at line 2123: attempt to index field '?' (a nil value).
  20. ↑ Template:ASN accident
  21. ↑ Template:ASN accident
  22. ↑ Template:ASN accident
  23. ↑ Template:ASN accident
  24. ↑ Template:ASN accident
  25. ↑ Template:ASN accident
  26. ↑ Template:ASN accident

External links

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