Soviet mid-range jet airliner
The
Yakovlev Yak-42
(
Russian
:
Яковлев Як-42
;
NATO reporting name
: "
Clobber
") is a 100/120-seat
three-engined
mid-range passenger jet developed in the mid 1970s to replace the technically obsolete
Tupolev Tu-134
. It was the first airliner produced in the
Soviet Union
to be powered by modern high-bypass
turbofan
engines.
[2]
Development
[
edit
]
In 1972, the
Yakovlev
design bureau
started work on a short- to 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 of 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 Yakovlev's smaller
Yak-40
. The requirement resulted in the largest, heaviest and most powerful aircraft designed by Yakovlev,
[3]
[4]
until the even larger
MC-21
took flight in 2017.
[
citation needed
]
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 first of three prototypes, which was fitted with an 11-degree wing and
registered
SSSR-1974
, made its maiden flight on 7 March 1975. It was followed by the second prototype, (
SSSR-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 (
SSSR-1976
) fitted with improved de-icing gear.
[6]
[7]
Design
[
edit
]
The Yak-42 is a low-winged
monoplane
of all-metal construction, with a design lifespan of 30,000 one-hour flights.
[8]
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.
[9]
All of the prototypes had main landing gear with two wheels each, with the first serial production aircraft, four main wheels were introduced.
[10]
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 flaps slotted.
[8]
[9]
[6]
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.
[9]
Operational history
[
edit
]
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 96 seats, giving a total of 104 seats.
[11]
[12]
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 throughout the Aeroflot fleet.
[13]
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 fatally
crash
near
Mazyr
. The type was grounded as a result, not returning to service until October 1984.
[14]
An export order for seven aircraft was announced in 1982 by
Aviogenex
of
Yugoslavia
, but the contract lapsed.
[12]
The availability of the longer-range Yak-42D variant from 1991 onwards gave rise to a few more export sales, to Bosnia, China, Cuba, and Iran.
[15]
As of 1 January 1995 a total of 185 Yak-42 had been produced, including 105 Yak-42Ds.
[1]
Variants
[
edit
]
- Yak-42
Original production version. Max. takeoff 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.
[14]
- Yak-42D
Long-range version (
Dal'niy
? long range) increased fuel. Replaced standard Yak-42 in production.
[15]
- 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.
[1]
- 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.
[1]
- 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
Irkut MC-21
.
[20]
Operators
[
edit
]
As of July 2019, 22 Yak-42s remained in commercial airline service. Operators are
Izhavia
(8),
KrasAvia
(10) and
Turukhan Airlines
(4).
[21]
[
needs update
]
Accidents and incidents
[
edit
]
As of 15 February 2018, nine fatal Yak-42 accidents have occurred with a total of 570 casualties.
- 28 June 1982
- Aeroflot Flight 8641
, a Yak-42 (CCCP-42529) lost control, entered a dive, broke up in mid-air and crashed near Verbovichi,
Naroulia District
,
Byelorussian Soviet Socialist Republic
following a failure of the horizontal stabilizer jackscrew due to fatigue caused by design flaws, killing all 132 on board. All Yak-42s were grounded until the defect was rectified in October 1984. The accident remains the deadliest involving the Yak-42 as well as the deadliest in Belarus to date.
[22]
- September 1986
- An Aeroflot Yak-42 (CCCP-42536) was being used for security forces training when a
thunderflash
ignited the interior. The aircraft burned out, but there were no casualties.
[23]
- 14 September 1990
- Aeroflot Flight 8175, a Yak-42 (CCCP-42351), struck trees and crashed short of the runway at
Koltsovo Airport
,
Sverdlovsk
,
Russian Soviet Federative Socialist Republic
after the pilot intentionally deviated from the approach pattern, killing four of 129 on board.
[24]
[25]
- 31 July 1992
- China General Aviation Flight 7552
, a Yak-42D (B-2755), overran the runway on takeoff from
Nanjing Dajiaochang Airport
,
China
after failing to lift off, killing 107 (or 108) of 126 on board. The horizontal stabilizer had been trimmed in the landing position.
[26]
- 20 November 1993
- Avioimpex Flight 110
, a Yak-42D (RA-42390) leased from Saravia, struck the side of Mount Trojani (near Ohrid,
North Macedonia
) due to pilot error, killing all 116 on board. Macedonian investigators blamed the accident on an inoperable VOR beacon and pilot error, while Russia claimed a misunderstanding from ATC because the controller spoke Macedonian while the crew used Russian and English in their transmissions. The accident remains the deadliest in North Macedonia.
[27]
- 17 December 1997
- Aerosvit Flight 241
, a Yak-42 (UR-42334) leased from Lviv Airlines, struck the side of Mount Pente Pigadia in the
Pierian Mountains
of
Greece
due to pilot error and confusion in the cockpit, killing all 70 on board.
[28]
- 25 December 1999
- Cubana de Aviacion Flight 310
, a Yak-42D (CU-T1285), struck San Luis hill while on approach to
Bejuma
,
Cuba
after the pilot radioed that he was descending 8,000 ft (2,400 m) to 4,000 ft (1,200 m) as part of the approach following a 40 minute hold, killing all 22 on board.
[29]
- 26 May 2003
- UM Airlines Flight 4230
, a Yak-42D (UR-42352) struck a mountain near
Macka
, Trabzon,
Turkey
in poor visibility due to pilot error, killing all 75 on board. The aircraft was flying 62 Spanish soldiers, members of the
ISAF
mission operating in
Afghanistan
, back to Spain.
[30]
- 7 September 2011
- 2011 Lokomotiv Yaroslavl plane crash
, a YAK-Service Yak-42D (RA-42434), stalled and crashed shortly after takeoff from
Tunoshna Airport
,
Yaroslavl
,
Russia
due to pilot error; of the 45 on board, only the mechanic survived; 29 members of the
KHL hockey
team
Lokomotiv Yaroslavl
were among the dead.
[31]
Specifications (Yak-42D)
[
edit
]
Data from
Brassey's World Aircraft & Systems Directory 1999/2000.
[16]
General characteristics
- Crew:
2 pilots plus optional flight engineer
- Capacity:
up to 120 passengers (normally eight 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 m
2
(1,600 sq ft)
- Airfoil
:
root:
TsAGI SR-9 (8.5%);
tip:
TsAGI SR-9 (6.5%)
[32]
- Empty weight:
33,000 kg (72,753 lb)
- Max takeoff weight:
57,500 kg (126,766 lb)
- Powerplant:
3 ×
Lotarev D-36
turbofan
engines, 63.75 kN (14,330 lbf) thrust each
Performance
- Maximum speed:
810 km/h (500 mph, 440 kn)
- Cruise speed:
740 km/h (460 mph, 400 kn)
- Range:
4,000 km (2,500 mi, 2,200 nmi)
- Service ceiling:
9,600 m (31,500 ft)
See also
[
edit
]
Related development
Aircraft of comparable role, configuration, and era
Related lists
References
[
edit
]
- ^
a
b
c
d
Gunston and Gordon 1997, p. 198.
- ^
Gunston, 1997
- ^
Gordon, Komissarov and Komissarov 2005, p. 311.
- ^
a
b
Gunston and Gordon 1997, p. 194.
- ^
Gordon, Komissarov and Komissarov 2005, pp. 311?312.
- ^
a
b
Gordon, Komissarov and Komissarov 2005, pp. 312?314.
- ^
Gunston and Gordon pp. 196?197.
- ^
a
b
Gunston and Gordon 1997, p. 195.
- ^
a
b
c
Taylor 1982, p. 241.
- ^
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
- ^
Gordon, Komissarov and Komissarov 2005, pp. 314?315.
- ^
a
b
Gunston and Gordon 1997, p. 197.
- ^
Flight International
30 January 1982, p. 208.
- ^
a
b
Gordon, Komissarov and Komissarov 2005, p. 315.
- ^
a
b
Gordon, Komissarov and Komissarov 2005, p. 316.
- ^
a
b
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.
- ^
Thisdell and Seymour
Flight International
30 July?5 August 2019, p. 47.
- ^
Accident description for CCCP-42529
at the
Aviation Safety Network
. Retrieved on 2 February 2016.
- ^
Accident description for CCCP-42536
at the
Aviation Safety Network
. Retrieved on 2 February 2016.
- ^
"Yak-42 crashes"
. CBC.
Archived
from the original on 16 January 2014
. Retrieved
15 January
2014
.
- ^
Accident description for CCCP-42351
at the
Aviation Safety Network
. Retrieved on 2 February 2016.
- ^
Accident description for B-2755
at the
Aviation Safety Network
. Retrieved on 2 February 2016.
- ^
Accident description for RA-42390
at the
Aviation Safety Network
. Retrieved on 2 February 2016.
- ^
Accident description for UR-42334
at the
Aviation Safety Network
. Retrieved on 2 February 2016.
- ^
Accident description for CU-T1285
at the
Aviation Safety Network
. Retrieved on 2 February 2016.
- ^
Accident description for UR-42352
at the
Aviation Safety Network
. Retrieved on 2 February 2016.
- ^
Accident description for RA-42434
at the
Aviation Safety Network
. Retrieved on 2 February 2016.
- ^
Lednicer, David.
"The Incomplete Guide to Airfoil Usage"
.
m-selig.ae.illinois.edu
. Retrieved
16 April
2019
.
- "Aeroflot completes one year of Yak-42 operations"
.
Flight International
, 30 January 1982. p. 208.
- [1]
- 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
.
- Thisdell, Dan and Morris, Rob. "World Airliner Census".
Flight International
, Vol. 194, No. 5650, 21 August?3 September 2018.
ISSN
0015-3710
. pp. 24?47.
- Thisdell, Dan and Seymour, Chris. "World Airliner Census".
Flight International
, Vol. 196, No. 5694, 30 July?5 August 2019.
ISSN
0015-3710
. pp. 24?47.
External links
[
edit
]
Media related to
Yakovlev Yak-42
at Wikimedia Commons
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