22 January 1971 Surgut Aeroflot Antonov An-12 crash

(Redirected from 1971 January 22 Surgut Aeroflot Antonov An-12 crash) Aviation accident in the Soviet Union Not to be confused with 31 January 1971 Surgut Aeroflot Antonov An-12 crash.

1971 January 22 Surgut Aeroflot Antonov An-12 crash
Accident
Aeroflot Antonov An-12 registered CCCP-11105, sister ship to the aircraft involved in the accident
Date	22 January 1971
Summary	Icing due to bleed air valves being closed
Site	Surgut, RSFSR, Soviet Union 61°20′36″N 73°24′12″E / 61.34333°N 73.40333°E / 61.34333; 73.40333
Aircraft
Aircraft type	Antonov An-12B
Operator	Aeroflot, Komi Civil Aviation Directorate
Registration	CCCP-11000
Flight origin	Omsk Tsentralny Airport (OMS/UNOO)
Destination	Surgut International Airport (SGC/USRR)
Passengers	2
Crew	12
Fatalities	14
Survivors	0

The 22 January 1971 Surgut Aeroflot Antonov An-12 crash occurred when an Aeroflot Antonov An-12B, registered CCCP-11000, flying from Omsk Tsentralny Airport, in the Soviet Union's (RSFSR) on 22 January 1971, crashed 15 km (9.3 mi) short of the runway on approach to Surgut International Airport, Surgut, RSFSR. An investigation found the aircraft's ice protection system was ineffective because the engine bleed air valves were closed during the flight; ice therefore built up on the aircraft causing it to go out of control.

Aircraft

The aircraft was an Antonov AN-12B with the aircraft registration 11000 (factory number - 5343610, a serial number showing some basic information about the aircraft, 5 for the last digit of the year of manufacture - 1965, 34 for the factory of origin - the Tashkent aviation factory, 36 for the production batch and 10 for the individual aircraft within that batch) this aircraft left the production line of the V. P. Chkalov Tashkent aviation production association on 3 December 1965 and by 2 February was handed over to the main directorate of the civil air fleet (the governmental organ tasked with overseeing aviation throughout the Soviet Union). The aircraft was then sent to the Syktyvkar aviation department of the Komi territorial directorate of the civil air fleet. At the time of the crash the aircraft had completed 5626 flying hours in total and 2578 landings.

Accident

In the first half of January 1971 CCCP-11000 was one of two Antonov AN-12s which, along with 3 crews from the 75th flying squadron were temporarily based at Omsk airport, these aircraft were used in transporting freight. On January 22 an order was received to fly CCCP-11000 to Syktyvkar, where routine maintenance work was to be carried out on the aircraft. It was decided to combine the flight with the delivery of 12 metric tons of freight to Surgut. The goods to be transported consisted mainly of rolls of netting, plastic floor tiles and other household goods, as well as a C-995 piledriver for use in construction. Aboard were two crews, the flight crew and a relief crew. The flight crew consisted of:

Captain - Sergei Alexeyavich Bakharev
Second officer - Anatoli Petrovich Dekhtarenko
Navigator - Valeriy Konstantinovich Bakhin
Flight mechanic-instructor - Mikhail Ivanovich Kazachkov
Radio operator - Anatoli Antonidovich Tichenko
Steward - Vladimir Mikhayilovich Malinin

The relief crew consisted of:

Captain - Leontiy Andreyevich Butov
Second officer - Anatoliy Mikhailovich Shama
Navigator - Pyotr Stepanovich Azarenkov
Flight mechanic - Anatoliy Mikhailovich Udayev
Radio operator - Nikolai Ivanovich Soklakov
Steward - Igor Ivanovich Pushnikov

Two others were also on board: an engineer from the 75th flying squadron; Nikolai Pavlovich Kayakan and loadmaster; Yevgeniya Rudolfovna Kramar. At Surgut, according to the weather forecast provided to the crew, there were Stratocumulus clouds at a height of 500–700 m (1,640.4–2,296.6 ft), visibility was 3–4 km (1.9–2.5 mi), there was snow, with icing conditions in the clouds. After take-off at 18:09 Moscow time from Omsk airport the AN-12 climbed to a flight level of 6,600 m (21,653.5 ft).

At Surgut there was solid cloud at a height of 450 m (1,476.4 ft) , visibility was 5.5 km (3.4 mi), a fresh breeze was blowing from the north and the air temperature was −9 °C (15.8 °F). At 19:20 the radar controller at Surgut gave permission for the crew of the AN-12 to descend to a height of 4,500 m (14,763.8 ft), and then to a height of 1,200 m (3,937.0 ft). When the crew reported that they had reached a height of 1,200 m (3,937.0 ft), they were ordered to contact landing control. They approached the runway on a magnetic heading of 180° and the aircraft entered the second turn of its circuit whilst descending to a height of 400 m (1,312.3 ft), the distance to the runway at this point was 11 km (6.8 mi). At 19:34 Moscow time the crew reported that they were passing the outer marker beacon at a height of 400 m (1,312.3 ft), which was acknowledged by the controller. At 19:36 Moscow time (21:36 local time), the aircraft was 11 km (6.8 mi) laterally and 16 km (9.9 mi) radially from the runway. The crew received the order to perform the third turn of their holding pattern, this instruction was acknowledged by the crew. This was the last communication that took place with the aircraft.

When the AN-12 was at a distance of 18 km (11.2 mi)to the North-East of Surgut airport at a speed of 330 km/h (205.1 mph) conducting a left turn, the aircraft experienced flow separation on the wing as a result of which it entered a progressive left turn and lost altitude. At this point, having deviated from its original course by 110°, and now on a bearing of 40° and with a left bank around 90° the aircraft crashed into the ground in the vicinity of the river Pochekuika and was completely destroyed with the wreckage catching fire.

Causes

According to an analysis of the weather conditions there was severe icing conditions at an altitude of 400–1,300 m (1,312.3–4,265.1 ft). Severe icing conditions at 1,200 m (3,937.0 ft) were also reported by the crew of CCCP-12996, another AN-12 involved in a very similar crash at the same airfield just 9 days later.

The conclusion of the commission: The aircraft suffered a stall at the third turn due to a sharp deterioration in its aerodynamics as a consequence of icing on the wing whilst flying through severe icing conditions, and also due to an inappropriate speed given for the third and fourth turns for an aircraft weighing 55 tons and with icing on the wings. Icing on the wings occurred due to insufficient heating of the leading edge of the wing resulting from incomplete opening of the air bleed valves from the engine.
Other factors:

A lack of flight testing on the behaviour of the aircraft with wing icing and a lack of recommendations to the crew for flying in such conditions.

A lack of data on the effectiveness of the aircraft's wing anti-icing system during intensive icing conditions.

Aftermath

In the span of 9 days (22nd and 31st of January 1971) two AN-12 aircraft crashed at Surgut, CCCP-11000 and CCCP-12996. Both crashes occurred under similar circumstances, whilst carrying out the third turn of their landing circuit both aircraft suffered spontaneous rolls due to flow separation on the wing caused by a drop in aerodynamics because of icing, which in turn was caused by ineffective de-icing systems since the hot air intake valve from the engine was not fully open. In order to prevent further catastrophes of the same nature significant improvements were made to the air bleed control systems including an indicator to show the fully open position of the valves. Special tests were also carried out, the results of which helped to clarify the aerodynamic characteristics of the AN-12 during icing. It also lead to changes in many civil aviation governing documents.

Portals:

References

"Accident description". Aviation Safety Network. Retrieved 1 January 2011.
Катастрофа Ан-12Б Коми УГА близ Сургута (in Russian). airdisaster.ru. Archived from the original on 2013-01-22. Retrieved 2014-08-28.
"Antonov AN-12B registration number CCCP - 11000". russianplanes.net. Retrieved 5 May 2021.
"Aviation forum - serial factory numbers (in russian)". aviaforum.ru. Retrieved 5 May 2021.
^ "Komi territorial aviation directorate AN-12B accident near Surgut (in Russian)". airdisaster.ru. Retrieved 2013-05-15.
"Антонов Ан-12Б Бортовой №: CCCP-11000". Russianplanes.net. Archived from the original on 2013-04-26. Retrieved 2013-05-15.

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Accidents and
incidents

1940s	G-2 Alma-Ata crash ANT-20bis crash CCCP-Л1450 crash Flight 17
1950s	Il-12 Karaganda crash Il-12 Novosibirsk crash Kemerovo mid-air collision Flight 229 Flight 783 Flight 10 Flight 136 Flight 214 Flight 229 Kiev mid-air collision Flight 11 Flight 10 Flight 105 Flight 04 Flight 365 Flight 164 Il-12 Lazo crash Тu-104 Kanash crash Flight 200 Flight 315
1960s	Flight 315 Flight 207 Flight 036 Flight 068 Flight 245 Flight 902 Flight 415 Flight 03 Flight 213 Flight 191 Flight 25 Flight 012 Flight 366 Flight 663 Flight 721 Flight 101/X-20 Flight 542 Flight 513 Flight 99 Flight 065 Flight 2723 Flight 5003 Flight 2230 Flight L-51 Flight 1668 Flight 15 Flight 831 Flight F-28 Flight N-826
1970s	Flight U-45 Flight 1661 Flight 3630 CCCP-11000 crash CCCP-12996 crash Flight 1969 Flight 1912 Flight 773 Flight N-63 Flight 2174 Flight 1491 Flight 558 Flight 1036 Flight 217 Flight 6263 Flight 141 Flight 630 Flight X-167 Flight 6551 Flight 109 Flight A-13 Flight 3932 Flight 964 Flight 19 Flight 2022 Flight 2420 CCCP-75559 crash Flight 662 Flight E-15 Flight A-53 Flight 2003 Flight 3739 Flight 909 Flight 1802 Flight 418 Flights 7957 and 31 Flight 2415 Flight N-36 Flight 3843 Flight 5003 Flight 331 Flight B-2 Flight 6709 Flight 1080 Flight 6515 Flight 1691 Flights 7628 and 7880 Flight 5484
1980s	Flight 4225 Flight 498 Flight 811 Flight 3603 Flight 8641 Flight 411 Flight 343 Flight 5463 Flight 601 Flight 3352 Flight F-637 Flight 3519 Flight 7841 Zolochiv mid-air collision Flight 5143 Flight 101/435 Flight F-77 Flight 2306 Flight 6502 Flight 892 Flight U-505 Flight N-528 Flight 699 Flight 3739
since 1990s	Flight E-35D CCCP-46472 crash Flight 2808 Flight 593 Flight 521 Flight 821 Flight 1492

v t e Aviation accidents and incidents in 1971 (1971)
Jan 7 B-52C Lake Michigan crashJan 18 Balkan Bulgarian Airlines Flight 130Jan 22 Surgut Aeroflot Antonov An-12 crashJan 30 Indian Airlines hijackingJan 31 Surgut Aeroflot Antonov An-12 crashMar 31 Aeroflot Flight 1969May 23 Aviogenex Flight 130May 28 Colorado Aviation Aero Commander 680Jun 6 Hughes Airwest Flight 706Jun 7 Allegheny Airlines Flight 485Jul 3 Toa Domestic Airlines Flight 63Jul 25 Aeroflot Flight 1912Jul 30 All Nippon Airways Flight 58Jul 30 Pan Am Flight 845Aug 28 Malév Flight 731Sep 4 Alaska Airlines Flight 1866Sep 6 Paninternational Flight 112Sep 13 Lin Biao incidentSep 16 Malév Flight 110Oct 2 British European Airways Flight 706Oct 10 Aeroflot Flight 773Nov 9 Aeroflot Flight N-63Nov 9 Livorno RAF Hercules crashNov 10 Indian Ocean Vickers Viscount crashNov 20 China Airlines Flight 825Nov 24 D. B. Cooper hijackingDec 1 Aeroflot Flight 2174Dec 2 Pakistan International Airlines Flight 712Dec 24 LANSA Flight 508
1970 ◄ ► 1972

Aviation accidents and incidents in 1971 (1971)

Jan 7 B-52C Lake Michigan crashJan 18 Balkan Bulgarian Airlines Flight 130Jan 22 Surgut Aeroflot Antonov An-12 crashJan 30 Indian Airlines hijackingJan 31 Surgut Aeroflot Antonov An-12 crashMar 31 Aeroflot Flight 1969May 23 Aviogenex Flight 130May 28 Colorado Aviation Aero Commander 680Jun 6 Hughes Airwest Flight 706Jun 7 Allegheny Airlines Flight 485Jul 3 Toa Domestic Airlines Flight 63Jul 25 Aeroflot Flight 1912Jul 30 All Nippon Airways Flight 58Jul 30 Pan Am Flight 845Aug 28 Malév Flight 731Sep 4 Alaska Airlines Flight 1866Sep 6 Paninternational Flight 112Sep 13 Lin Biao incidentSep 16 Malév Flight 110Oct 2 British European Airways Flight 706Oct 10 Aeroflot Flight 773Nov 9 Aeroflot Flight N-63Nov 9 Livorno RAF Hercules crashNov 10 Indian Ocean Vickers Viscount crashNov 20 China Airlines Flight 825Nov 24 D. B. Cooper hijackingDec 1 Aeroflot Flight 2174Dec 2 Pakistan International Airlines Flight 712Dec 24 LANSA Flight 508

1970 ◄ ► 1972

v t e Aviation accidents and incidents in the Soviet Union in the 1970s
1970	Batagay Aeroflot An-24 crash (28 January 1970) Aeroflot Flight 145 (29 January 1970) Aeroflot Flight U-45 (February 1970) Aeroflot Flight 1661 (April 1970) Dymshits–Kuznetsov hijacking affair (June 1970) Aeroflot Flight 3630 (September 1970) Aeroflot Flight 244 (October 1970)
1971	Surgut Aeroflot An-12 crash (22 January 1971) Surgut Aeroflot An-12 crash (31 January 1971) Aeroflot Flight 1969 (March 1971) Aeroflot Flight 1912 (July 1971) Malév Flight 110 (September 1971) Aeroflot Flight 773 (October 1971) Aeroflot Flight N-63 (November 1971) Aeroflot Flight 2174 (December 1971)
1972	Aeroflot Flight B-608 (4 May 1972) Svetlogorsk An-24 crash (16 May 1972) Aeroflot Flight 1491 (18 May 1972) Aeroflot Flight 558 (August 1972) Aeroflot Flight 1036 (1 October 1972) Aeroflot Flight 217 (13 October 1972) Japan Air Lines Flight 446 (November 1972)
1973	Aeroflot Flight 6263 (January 1973) Aeroflot Flight 630 (24 February 1973) Aeroflot Flight X-167 (28 February 1973) Balkan Bulgarian Airlines Flight 307 (March 1973) Aeroflot Flight 2420 (April 1973) Aeroflot Flight 6551 (11 May 1973) Aeroflot Flight 109 (18 May 1973) Aeroflot Flight A-13 (August 1973) Aeroflot Flight 3932 (September 1973) Aeroflot Flight 964 (October 1973) Aeroflot Flight 19 (November 1973) Aeroflot Flight 2022 (December 1973)
1974	Aeroflot Flight H-75 (January 1974) Leningrad Aeroflot Il-18 crash (April 1974)
1975	Aeroflot Flight E-15 (July 1975) Aeroflot Flight 6274 (November 1975)
1976	Aeroflot Flight 2003 (January 1976) Aeroflot Flight 3739 (February 1976) Aeroflot Flight 909 (March 1976) Aeroflot Flight 1802 (May 1976) Anapa mid-air collision (September 1976) Aeroflot Flight 2415 (November 1976) Aeroflot Flight N-36 (December 1976)
1977	Aeroflot Flight 3843 (January 1977) Aeroflot Flight 5003 (February 1977) Tavda mid-air collision (May 1977) Aeroflot Tu-134 hijacking (10 July 1977) Aeroflot Flight B-2 (20 July 1977)
1978	Korean Air Lines Flight 902 (April 1978) Aeroflot Flight 6709 (19 May 1978) Yegoryevsk Tu-144 crash (23 May 1978) Iranian Chinook shootdown (June 1978) Aeroflot Flight 1080 (7 October 1978) Aeroflot Flight 6515 (23 October 1978)
1979	Aeroflot Flight 1691 (March 1979) Dniprodzerzhynsk mid-air collision (11 August 1979) Aeroflot Flight 5484 (29 August 1979)
1960–1969 ◄ 1970–1979 ► 1980–1991

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