|Centre-Avia Yak-42D in 2006|
|Role||Narrow-body Jet airliner|
|Built by||Saratov Aviation Plant|
|First flight||7 March 1975|
|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.
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.
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.
The Yak-42 is a low-winged monoplane of all metal construction, with a design lifespan of 30,000 one-hour flights. 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.
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.
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.
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.
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.
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. 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.
An export order for seven aircraft was announced in 1982 by Aviogenex of Yugoslavia, but the contract lapsed. The availability of the longer-range Yak-42D variant from 1991 onwards gave rise to a few more export sales, to Cuba and China. As of 1 January 1995 a total of 185 Yak-42 had been produced, including 105 Yak-42D.
Original production version. Max take-off weight 54,000 kg (119,050 lb).
Long-range version (Dahl'niy – long range) increased fuel. Replaced standard Yak-42 in production.
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.
Conversion of a Yak-42 for geophysical survey and environmental monitoring. Fitted with large underwing pods containing electro-optical sensors.
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.
- Air Romania (AiRom 2000)
Accidents and incidents
|This section needs additional citations for verification. (March 2012)|
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|
Data from Brassey's World Aircraft & Systems Directory 1999/2000 
- 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
- Maximum speed: 810 km/h (437 knots, 503 mph) (maximum cruise)
- Cruise speed: 740 km/h (399 knots, 460 mph) (economy cruise)
- Range: 4,000 km (2,158 nmi, 2,458 mi)(with maximum fuel)
- Service ceiling: 9,600 m (31,500 ft)
- Related development
- Aircraft of comparable role, configuration and era
- Yak-42 production numbers[verification needed]
- Gunston, 1997
- Gordon, Komissarov and Komissarov 2005, p. 311.
- Gunston and Gordon 1997, p. 194.
- Gordon, Komissarov and Komissarov 2005, pp. 311–312.
- Gunston and Gordon 1997, p. 195.
- Taylor 1982, p. 241.
- Gordon, Komissarov and Komissarov 2005, pp. 312–314.
- Gunston and Gordon pp. 196–197.
- Gordon, Komissarov and Komissarov 2005, pp. 314–315.
- Gunston and Gordon 1997, p. 197.
- Flight International 30 January 1982, p. 208.
- Gordon, Komissarov and Komissarov 2005, p. 315.
- Gordon, Komissarov and Komissarov 2005, p. 316.
- Gunston and Gordon 1997, p. 198.
- Taylor 1999, pp. 227–228.
- Gordon, Komissarov and Komissarov 2005, pp. 317–318.
- Gordon, Komissarov and Komissarov 2005, p. 318.
- Gordon, Komissarov and Komissarov 2005, pp. 319–320.
- Gordon, Komissarov and Komissarov 2005, pp. 320–321.
- "Top KHL squad killed in passenger plane crash in Russia". RT News. Retrieved 7 September 2011.
- "Aeroflot completes one year of Yak-42 operations". 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.
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