The Tupolev Tu-104 (NATO reporting name: Camel) is a medium-range, narrow-body, twin turbojet-powered Soviet airliner. It was the second jetliner to enter regular service, after the British de Havilland Comet and was the only jetliner operating in the world from 1956 to 1958, when the British jetliners were grounded after several crashes.
In 1957, Czechoslovak Airlines – ČSA (now Czech Airlines) became the first airline in the world to fly a route exclusively with jet airliners, using the Tu-104A variant between Prague and Moscow. In civilian service, the Tu-104 carried over 90 million passengers with Aeroflot (then the world's largest airline), and a lesser number with ČSA, while it also was operated by the Soviet Air Force. Its successors included the Tu-124, Tu-134, and Tu-154.
Design and development At the beginning of the 1950s, the Soviet Union's Aeroflot airline needed a modern airliner with better capacity and performance than the piston-engined aircraft then in operation. The design request was filled by the Tupolev OKB, which based their new airliner on its Tu-16 "Badger" strategic bomber. The wings, engines, and tail surfaces of the Tu-16 were retained with the airliner, but the new design adopted a wider, pressurised fuselage designed to accommodate 50 passengers. The prototype built in MMZ 'Opit' first flew on June 17, 1955, with Yu.L. Alasheyev at the controls. It was fitted with a drag parachute to shorten the landing distance by up to , since at the time, not many airports had sufficiently long runways. The first serial TU-104 took off on 5 November 1955.
The Tu-104 was powered by two Mikulin AM-3 turbojets placed in the wing roots, like the Tu-16. The crew consisted of two pilots, a navigator (seated in the glazed "bomber" nose), a flight engineer, and a radio operator (later eliminated). The airplane raised great curiosity by its lavish "Victorian" interior – so-called by some Western observers – due to the materials used: mahogany, copper, and lace.
Tu-104 pilots were trained on the Ilyushin Il-28 bomber, followed by mail flights on an unarmed Tu-16 bomber painted in Aeroflot colors, between Moscow and Sverdlovsk. Pilots with previous Tu-16 experience transitioned into the Tu-104 with relative ease. The Tu-104 was considered difficult to fly, as it was heavy on controls and quite fast on final approach, and at low speeds displayed a tendency to stall, a feature common with highly swept wings. Experience with the Tu-104 led the Tupolev Design Bureau to develop the world's first turbofan series-built airliner, the Tupolev Tu-124, designed for local markets, and subsequently the Tu-134.
Operational history
On 15 September 1956, the Tu-104 began revenue service on Aeroflot's Moscow-Omsk-Irkutsk route, replacing the Ilyushin Il-14. The flight time was reduced from 13 hours and 50 minutes to 7 hours and 40 minutes, and the new jet dramatically increased the level of passenger comfort. By 1957, Aeroflot had placed the Tu-104 in service on routes from Vnukovo Airport in Moscow to London, Budapest, Copenhagen, Beijing, Brussels, Ottawa, Delhi, and Prague.
In 1957, ČSA Czechoslovak Airlines became the only export customer for the Tu-104, placing the aircraft on routes to Moscow, Paris, and Brussels. ČSA bought six Tu-104As (four new and two used aircraft) configured for 81 passengers. Three of these were subsequently written off (one due to a refueling incident in India and another to a pilot error without fatalities).
In 1959, a Tu-104 was leased to Sir Henry Lunn Ltd. (Lunn Poly) of London, who used the aircraft to transport holiday-makers to Russia with a 4.5-hour flight time.
Whilst the Tu-104 continued to be used by Aeroflot throughout the 1960s and 1970s, the safety record of the aircraft was poor in comparison to Western jetliners (16 of 96 aircraft were lost in accidents). The Tu-104 was unreliable, heavy, and very unstable with poor control response and an inclination to Dutch roll. Poor design aerodynamics of the wings resulted in a propensity to stall with little or no warning and a dangerous tendency to pitch up violently before stalling and entering an irrecoverable dive. Due to the fear of inadvertent stalls, aircrew flew approaches above the recommended approach speed, landing at , nearly faster. At least two accidents were attributed to the pitch-up phenomenon, prompting changes to the design of the aircraft and operating procedures, but the problem remained. Aeroflot retired the Tu-104 from civilian service in March 1979 following a fatal accident at Moscow, but several aircraft were transferred to the Soviet military, which used them as staff transports and to train cosmonauts in zero gravity. After a military Tu-104 crash in February 1981 killed 50 people (17 were senior army and naval staff), the type was permanently removed from service. The last flight of the Tu-104 was a ferry flight to Ulyanovsk Aircraft Museum on 11 November 1986.
Variants
Data from:
Tu-104 – The initial version seating 50 passengers, it used two Mikulin AM-3 turbojet engines, each with of thrust; 29 airframes were built. Tu-104 2NK-8 – Projected version powered by two Kuznetsov NK-8 turbofan engines. Tu-104A – An improved version appearing in June 1957, its continued improvements of the Mikulin engines (Mikulin AM-3M each with of thrust) permitted significant growth in capacity, resulting in a 70-seater variant. The Tu-104A became the definitive production variant. On 6 September 1957, it flew with 20 t of payload at above mean sea level. On 24 September 1957, it reached average speed with a 2-tonne payload. In total, 80 airframes were built, of which six were exported to Czechoslovakia. Tu-104AK – A zero-gravity trainer conversion of the Tu-104A for cosmonaut training. Tu-104A-TS – Five Tu-104As converted to troop transport/casualty evacuation aircraft. Tu-104B – Further improvements were made by stretching the fuselage and fitting new Mikulin AM-3M-500 engines ( of thrust each). The Tu-104B was able to accommodate 100 passengers. This variant took advantage of the newer fuselage from the Tu-110 and the existing wings. It began revenue service with Aeroflot on 15 April 1959 on the Moscow-Saint Petersburg route; 95 airframes were built. Most were later rebuilt to Tu-104B-115 standard. Tu-104B-115 – Tu-104B airframes were rebuilt to accommodate 115 passengers, with new radio and navigational equipment. Tu-104B-TS – Six Tu-104Bs converted to troop transport/casualty evacuation aircraft. Tu-104 CSA - Six aircraft built for CSA. Tu-104D – This VIP version had two sleeper cabins forward and a 39-seat cabin aft. Tu-104D-85 – Tu-104A airframes rebuilt to accommodate 85 passengers. Tu-104D 3NK-8 – Projected version with three Kuznetsov NK-8 engines, new wings and a T-tail, precursor of Tu-154. Tu-104E – Experimental version powered by two Zubets RD-16-15 engines, giving better fuel economy and greater thrust. Two prototypes were converted from Tu-104Bs СССР-42441 and СССР-42443. The program was cancelled in the mid-1960s in favor of the Tu-154. Tu-104G – Version with a revised passenger cabin layout. Not to be confused with the so-called "Tu-104G", a de-militarized mailplane version of the Tu-16. Tu-104LL – Several serial numbers were converted for use in testing Tu-129 and Tu-22M electronics, and air-to-air missile systems (including launch). Tu-104Sh – Navigator trainer in two versions. Tu-104V – Tu-104B rebuilt to accommodate 117 passengers. Not built. Tu-107 – Prototype military transport version, with a rear loading ramp and a defensive turret armed with paired cannon. Although one aircraft was built, no production followed. Tu-110 – A four-engine version intended for export. A number of prototypes were built before the project was cancelled. Tu-118 – A projected turboprop version powered by four Kuznetsov TV-2F engines. Tu-124 – A separate development designed as a 75% scaled-down regional airliner based on the Tu-104. It featured major equipment upgrades, being a commercial airliner powered by fuel-efficient Soloviev D-20P turbofan engines. To support operations from shorter and unpaved airfields, it was equipped with low-pressure tires, double-slotted flaps, an automatic spoiler system, a center-section airbrake, and a rear-deploying drogue landing parachute.
Former operators
CSA Czechoslovak Airlines – six aircraft Czechoslovak Air Force
Military of Mongolia
Aeroflot Soviet Air Force
Accidents and incidents According to the American Flight Safety Foundation, between 1958 and 1981, 16 Tu-104s were lost in crashes out of 37 aircraft written off (hull loss rate = 18%) with a total of 1140 fatalities.
1950s 19 February 1958 An Aeroflot Tu-104 (СССР-Л5414) was being ferried from Sverdlovsk (now Yekaterinburg) to Moscow when it force-landed short of the runway at Savasleika Air Base due to fuel exhaustion; all three crew survived.
15 August 1958 Aeroflot Flight 04, a Tu-104A (СССР-Л5442), stalled, spun down and crashed in the Khabarovsky District, Khabarovsk Krai after entering an updraft at , killing all 64 on board in the first fatal accident involving the Tu-104. Later accidents showed that the Tu-104 was prone to losing longitudinal stability when flying in certain atmospheric conditions.
17 October 1958 An Aeroflot Tu-104A (СССР-42362) pitched up, entered a dive, spun down and crashed near Kanash after encountering turbulence and an updraft, killing all 80 on board. The aircraft was flying high-level diplomats of several Soviet-aligned countries to Moscow for an official event. In the wake of this accident, the Tu-104 was limited to and the stabilizers were redesigned.
1960s 20 October 1960 Aeroflot Flight 05, a Tu-104A (СССР-42452), struck sloping terrain near Ust-Orda while attempting to climb following an aborted approach after the nosegear light malfunctioned, killing the 3 pilots of 68 on board.
1 February 1961 An Aeroflot Tu-104A (СССР-42357) overran the runway on landing at Vladivostok Airport after landing too late; no casualties.
16 March 1961 Aeroflot Flight 068, a Tu-104B (СССР-42438) force-landed on the frozen Nizhneisetsky pond near Koltsovo Airport following double engine failure, killing five of 51 on board. Shortly after takeoff, the right engine failed, causing severe vibration of the fuselage. Because of the vibration, the crew could not determine which engine failed as they could not read the instruments. A crew member pulled back the throttle for the left engine in an attempt to hear the difference in engine power to determine which engine failed, but the engine was shut down by mistake. A loss of altitude resulted, and a forced landing was carried out. The aircraft also struck a house near the pond, killing two. The engine failure was caused by a broken turbine blade in the second stage of the turbine section.
10 July 1961 Aeroflot Flight 381, a Tu-104B (СССР-42447), crashed at Odessa-Central Airport in bad weather after encountering downdrafts during the approach, killing one of 94 on board.
17 September 1961 An Aeroflot Tu-104A (СССР-42388) was written off following a hard landing at Tashkent Airport; no casualties.
2 November 1961 An Aeroflot Tu-104B (СССР-42504) force-landed in a field near Vladivostok Airport due to engine failure after striking a radio antenna during the approach; no casualties.
4 June 1962 An Aeroflot Tu-104B (СССР-42491) struck the side of Mount Baba (19 mi northeast of Vrazhdebna Airport) while attempting to return to Sofia following engine failure, killing the five crew.
30 June 1962 Aeroflot Flight 902, a Tu-104A (СССР-42370), was shot down by an errant anti-aircraft missile and crashed in the Beryozovsky District, killing all 84 on board. The missile was fired during an air defense exercise in the Magansk area, but it had lost its target in a storm front and hit the Tu-104 instead.
3 September 1962