Yakovlev Yak-40K

The Yak-40 was built for Soviet local routes, where the same aircraft had to move both passengers and goods between modest airfields, many of them unpaved. The production version was a passenger aircraft and offered no practical way to get bulky loads into the cabin. The answer was the Yak-40K, a convertible configuration: according to the airwar.ru encyclopedia it was created on the basis of the standard 32-seat production aircraft and allows the passenger cabin to be quickly rearranged as a mixed passenger-cargo cabin or as a pure freight hold. Russian-language Wikipedia describes it the same way, as a modification for cargo and mixed passenger-cargo transport built on production aircraft.

What sets the version apart at a glance is its cargo door. English-language Wikipedia simply calls it a large freight door; the Spanish-language article places it on the left side of the fuselage, behind the entry door. None of the sources consulted gives its dimensions, so none are offered here.

The Russian sources do agree on the load figures. As a pure freighter the maximum payload was raised to 3200 kg. In mixed configuration the aircraft carries 10 to 18 passengers, with a maximum cargo weight of 2150 to 1150 kg respectively: the more seats are fitted, the less freight goes in. airwar.ru sums up the benefit in plain terms: a convertible aircraft can be used more flexibly and therefore more economically than one dedicated to a single role.

The three sources that date the version (airwar.ru and the Russian and English Wikipedias) put it in production from 1975 to 1981. Spanish-language Wikipedia ties it to the fourth and final production series of the Yak-40, introduced in 1975 with a higher payload and the option of a two-class cabin or a quick conversion into a freighter, and notes that "some units" were built in that cargo fit. No source gives a specific number of Yak-40Ks, so that figure is left open here.

The end came with the end of the type itself. Russian-language Wikipedia explains that series production of the Yak-40 stopped in 1981 because the factory switched to building the new Yak-42, and adds as a second reason the economy campaign then under way in the country.

Most Yak-40Ks flew with Aeroflot, but the type's accident list records other users. Angola's TAAG had at least two: D2-TYC, lost with all 19 on board near Matala on 8 June 1980, probably shot down by a Zambian Shenyang J-6, and D2-TYD, which overran the runway on landing at Luanda on 8 January 1988 without casualties. Also listed are a Yak-40K of the Soviet aviation industry ministry assigned to the Arsenyev plant (CCCP-87201), which failed to lift off at Omsukchan through overloading on 15 August 1983 and overran the runway, all nine on board surviving, and Kazakhstan Airlines' UN-88181, which ran off the runway at Dzhambul in severe crosswinds on 13 April 1995; all 31 on board survived.

Among the Aeroflot aircraft, CCCP-87930 came down in a dacha colony near Chardzhou airport on 20 March 1979 after flying into the wake turbulence of an Mi-6, and all 35 on board survived; CCCP-87946 force-landed near Tikhoretsk on 31 October 1979 with all three engines stopped by fuel exhaustion after a weather diversion, its five crew unhurt; and CCCP-87914 ran off the runway at Pavlodar on 9 September 1990 and struck Yak-40 CCCP-87451, writing off both aircraft.

The cargo door had its tragic side too. On 13 October 1977, on Aeroflot Flight 75 from Rostov-on-Don to Mykolaiv, the cargo hatch of a Yak-40 built in 1976 (CCCP-87948) opened in cruise, and a mother and her child were thrown out of the aircraft. The investigation commission concluded that the flight engineer had failed to secure it before a passenger flight. The source does not state the aircraft's sub-variant.

At least one example is preserved: Yak-40K CCCP-87490, in Aeroflot colours, at the Central Air Force Museum at Monino, according to the list of preserved aircraft in Russian-language Wikipedia.