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Yakovlev Yak-42D

Yak-42
Centre-Avia Yak-42D in 2006
Role Narrow-body Jet airliner
Manufacturer Yakovlev
Design group Yakovlev
Built by Saratov Aviation Plant
First flight 7 March 1975
Introduction 1980
Status Active
Produced 1980–2003
Number built 178[1]
Developed from Yakovlev Yak-40

The Yakovlev Yak-42 (NATO reporting name: "Clobber") is a 100/120-seat three-engined mid-range passenger jet. It was designed as a replacement for several obsolete Aeroflot jets as a mid-range passenger jet. It was also the first airliner produced in the Soviet Union to be powered by modern high-bypass turbofan engines.[2]

Design and development


In 1972, the Yakovlev design bureau started work on a short-medium, range airliner capable of carrying 100–120 passengers. It was intended to be a replacement for the Tupolev Tu-134 jet as well as the Ilyushin Il-18, Antonov An-24 and An-26 turboprop airliners. While the new airliner was required to operate out relatively small airfields while maintaining good economy, as many Soviet airports had been upgraded to accommodate more advanced aircraft, it did not have to have the same ability to operate from grass strips as the Yakovlev's smaller Yak-40. The requirement resulted in the largest, heaviest and most powerful aircraft designed by Yakovlev so far.[3][4]

Initial design proposals included a straight-wing airliner powered by two Soloviev D-30 turbofans and resembling an enlarged Yak-40, but this was rejected as it was considered uncompetitive compared to Western airliners powered by high bypass ratio turbofans. Yakovlev settled on a design powered by three of the new Lotarev D-36 three-shaft high bypass turbofans, which were to provide 63.90 kN (14,330 lbf) of thrust. Unlike the Yak-40, the new airliner would have swept wings.[4][5]

The Yak-42 is a low-winged monoplane of all metal construction, with a design lifespan of 30,000 one-hour flights.[6] It has a pressurised fuselage of circular section, with the cabin designed to carry 120 passengers in six abreast layout (or 100 passengers for local services with greater space allocated to carry-on luggage and coat stowage). The aircraft is flown by a flight crew of two pilots sitting side-by-side in a flight deck forward of the cabin. Access is via two airstairs, one in the underside of the rear fuselage, like that of the Yak-40, and one forward of the cabin on the port side. Two holds are located under the cabin, carrying baggage, cargo and mail.[7]

The wing layout underwent considerable revision during the design process, with the first prototype being built with a wing sweep of 11 degrees and the second prototype with a sweep of 23 degrees. After evaluation, the greater sweep of the second prototype was chosen for production. Early aircraft had a clean wing leading edge with no control surfaces, and plain trailing edge flaps. This changed in later aircraft, which were fitted with leading edge slats, with the trailing edge slats slotted.[6][7][8]

Two engines were mounted in pods on either side of the rear fuselage, with the third embedded inside the rear fuselage, fed with air via an "S-duct" air inlet. An auxiliary power unit (APU) is also fitted in the rear fuselage. No thrust reversers are fitted. The aircraft has a T-tail, with both the vertical fin and the horizontal surfaces swept.[7]

Operational history

Testing

The first of three prototypes, which was fitted with an 11 degree wing and registered CCCP-1974, made its maiden flight on 7 March 1975. It was followed by the second prototype, (CCCP-1975) with the 23 degree wing and a cabin with 20 rows of windows instead of 17 in the first prototype, and a third prototype (CCCP-1976) fitted with improved de-icing gear.[8][9]

In service

The first production aircraft was completed on 28 April 1978, with the first scheduled passenger flight, on the Aeroflot Moscow-Krasnodar route taking place on 22 December 1980. Production was at first slow, with only 10 flown by mid-1981. Initial aircraft were fitted for 120 seats in a three-plus-three arrangement. This was soon changed to a first class section with two-plus-two seating, and a main cabin with ninety six seats, giving a total of 104 seats.[10][11]

In its first year of operation Aeroflot's Yak-42s carried about 200,000 passengers, mainly on routes from Moscow, but also on international services from Leningrad to Helsinki and from Donetsk to Prague, with the type being planned to enter wider service throghout the aeroflot fleet.[12] On 28 June 1982, however, the tailplane detached from an Aeroflot Yak-42 in flight owing to a failure of the actuator screw jack, causing the aircraft to crash fatally near Mazyr. The type was grounded as a result, not returning to service until October 1984.[13]

An export order for seven aircraft was announced in 1982 by Aviogenex of Yugoslavia, but the contract lapsed.[11] The availability of the longer-range Yak-42D variant from 1991 onwards gave rise to a few more export sales, to Cuba and China.[14] As of 1 January 1995 a total of 185 Yak-42 had been produced, including 105 Yak-42D.[15]

Variants

Yak-42

Original production version. Max take-off weight 54,000 kg (119,050 lb).[16]

Yak-42ML

Version with modified avionics for use on international use (mezhdunarodnyye linii – international services). Entered service in July 1981 on the Leningrad-Helsinki route.[13]

Yak-42D

Long-range version (Dahl'niy – long range) increased fuel. Replaced standard Yak-42 in production.[14]

Yak-142

Derivative of Yak-42D with updated, western AlliedSignal avionics, spoilers to allow faster descent and enlarged cabin door to accommodate jet bridge. Also designated Yak-42A, Yak-42-100 and Yak-42D-100.[17]

Yak-42R

Yak-42 used as testbed for radar for Yakovlev Yak-141 fighter.[15]

Yak-42F

Conversion of a Yak-42 for geophysical survey and environmental monitoring. Fitted with large underwing pods containing electro-optical sensors.[18]

Yak-42LL

Conversion as testbed for Progress D-236 propfan engine. Single D-236 (rated at 8,090 kW (10,850shp)) mounted in place of starboard engine, on special pylon to give sufficient clearance for 4.2 m (13 ft 9¾ in) propellers. First flew 15 March 1991.[15]

Yak-42M

A projected but unbuilt stretched airliner. Planned to be powered by three Progress D-436 turbofans, a stretched fuselage and new wings. Design developed into Yak-242.[19]

Yak-242

Further developed Yak-42M, with two underwing Aviadvigatel PS-90 turbofans. Design evolved into MS-21.[20]

Operators



As of 24 November 2011, a total of 91 Yakovlev Yak-42 aircraft remain in airline service.[1]

 Kazakhstan
 Russia

Former operators

 Armenia
 Cuba
 Pakistan
 Russia /  Soviet Union
 Macedonia
 Moldova
 Latvia
 Lithuania
 Romania
  • Air Romania (AiRom 2000)
 Ukraine
 Indonesia
 Sudan

Accidents and incidents

As of 7 September 2011, nine Yak-42 fatal accidents occurred with total of 591 casualties.

Date Aircraft registration Location Fatalities Brief description
June 28, 1982 СССР-42529 near Mazyr, south central Belarus 132/132 Flight Leningrad-Kiev, damage to stabilizer due to mechanical deterioration, diving and disintegrating in mid-air. All Yak-42 flights were suspended until the design error was fixed. This was the deadliest Yak-42 crash, and the deadliest air crash in Belarus.
September 14, 1990 СССР-42351 Koltsovo, southeast of Yekaterinburg 4/128 Flight Volgograd-Sverdlovsk, crew error on final approach.
July 31, 1992 B-2755 Nanjing, west of Shanghai 108/126 Crashed on take-off due to mechanical failure.
November 21, 1993 RA-42390 Near Ohrid, southwestern Macedonia 116/116 Flight Geneva-Skopje, which had diverted to Ohrid, crashed into a mountain in difficult weather conditions, near Ohrid, Republic of Macedonia.
December 17, 1997 UR-42334 Mount Pieria, southwest of Thessaloniki 70/70 Flight Odessa-Saloniki, crew error on going around, crashed into a mountain.
December 25, 1999 CU-T1285 Bejuma, west of Caracas 22/22 Havana, Cuba – Valencia, Venezuela the aircraft impacted a hill on approach.
May 26, 2003 UR-42352 Near Trabzon, north-eastern Turkey 75/75 Flight Bishkek-Trabzon-Saragossa managed by UM Airlines, crashed into a mountain on the final approach in fog. 62 Spanish soldiers, members of the ISAF mission operating in Afghanistan, and 13 crew died.
September 7, 2011 RA-42434 Near Yaroslavl, 250 km northeast of Moscow 44/45 Yak-Service flight en route to Minsk from Yaroslavl carrying the KHL Russian hockey team Lokomotiv Yaroslavl. Caused by a pilot error while taking off from Tunoshna Airport and crashed, killing 44 people[21]

Specifications (Yak-42D)

Data from Brassey's World Aircraft & Systems Directory 1999/2000 [16]

General characteristics
  • Crew: two pilots plus optional flight engineer
  • Capacity: up to 120 passengers (But usually 8 first class and 96 economy class)
  • Length: 36.38 m (119 ft 4 in)
  • Wingspan: 34.88 m (114 ft 5 in)
  • Height: 9.83 m (32 ft 3 in)
  • Wing area: 150.0 m² (1,615 ft²)
  • Empty weight: 33,000 kg (72,752 lb)
  • Max. takeoff weight: 57,500 kg (126,765 lb)
  • Powerplant: 3 × Lotarev D-36 turbofan, 63.75 kN (14,330 lbf) each

Performance

See also

Related development
Aircraft of comparable role, configuration and era

References

  • Flight International, 30 January 1982. p. 208.
  • Gordon, Yefim, Dmitry Komissarov and Sergey Komissarov. OKB Yakovlev: A History of the Design Bureau and its Aircraft. Hinkley, UK: Midland Publishing, 2005. ISBN 1-85780-203-9.
  • Gunston, Bill and Yefim Gordon. Yakovlev Aircraft since 1924. London, UK: Putnam Aeronautical Books, 1997. ISBN 1-55750-978-6.
  • Taylor, Joihn W. R. Jane's All The World's Aircraft 1982–83. London: Jane's Yearbooks, 1982. ISBN 0-7106-0748-2.
  • Taylor, Michael J. H. Brassey's World Aircraft & Systems Directory 1999/2000. London: Brassey's, 1999. ISBN 1-85753-245-7.

External links

  • Yakovlev design bureau official site

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