Tupolev Tu-144

Given the vast size of the Soviet Union, supersonic travel was seen as economically feasible, especially for government employees travelling between Moscow and Siberian cities. Flying was the only practical alternative to week-long rail journeys, and supersonic transport could significantly cut travel times. While the idea of SSTs was controversial in the West due to noise and environmental pollution concerns, the Soviet Union planned to continue with their development, largely for its long Siberian and Central Asian routes. With ample airspace, flight corridors were likely to avoid built-up areas. Even if international landing rights were not granted, the Tu-144 could still be used for domestic and regional flights. Aeroflot, the flag carrier of the Soviet Union, had an extensive network of interconnected airfields and increasing international reach, with hopes of extending flights to Sydney, Australia. Initial estimates suggested that 20 Tu-144s would suffice for Aeroflot's domestic and international needs. The aircraft was seen as a formidable challenge to the United States' dominance in the field of civil aviation. ==Development==

Analog, used as a testbed for the Tu-144's wing deployed and drooped nose Tu-144 at the Paris Air Show in 1975. The Soviet government published the concept of the Tu-144 in an article in the January 1962 issue of the magazine Technology of Air Transport. The air ministry started development of the Tu-144 on 26 July 1963, 10 days after the design was approved by the Council of Ministers. The plan called for five flying prototypes to be built in four years, with the first aircraft to be ready in 1966. Despite the similarity in appearance of the Tu-144 to the Anglo-French supersonic aircraft (which earned it the nickname "Concordski"), there were significant differences between the two aircraft. The Tu-144 is bigger and faster than the Concorde (M2.15 vs. M2.04). Concorde used an electronic engine control package from Lucas, which Tupolev was not permitted to purchase for the Tu-144 as it could also be used on military aircraft. Concorde's designers used fuel as coolant for the cabin air conditioning and for the hydraulic system (see Concorde for details). Tupolev also used fuel/hydraulic heat exchangers, but used cooling turbines for the cabin air. While both Concorde and the Tu-144 prototype had ogival delta wings, the Tu-144's wing lacked Concorde's conical camber. Production Tu-144s replaced this wing with a double delta wing including spanwise and chordwise camber. They also added two small retractable surfaces called a moustache canard, with fixed double-slotted leading-edge slats and retractable double-slotted flaps. These were fitted just behind the cockpit and increased lift at low speeds. Moving the elevons downward in a delta-wing aircraft increases the lift, but also pitches its nose downward. The canards cancel out this nose-downwards moment, thus reducing the landing speed of the production Tu-144s to . ==Design==

Along with early Tu-134s, the Tu-144 was one of the last commercial aircraft with a braking parachute. The Tu-144 was not fitted with any reverse thrust capabilities, and so the parachute was used as the sole alternative. ;Materials: The aircraft was designed for a 30,000-hour service life over 15 years. Airframe heating and the high temperature properties of the primary structural materials, which were aluminium alloys, set the maximum speed at Mach 2.2. and were not necessary for supersonic cruise; the Tu-144 used maximum afterburner for take-off and minimum for cruise. The intakes were to be shortened by 10 feet on the projected Tu-144M. The RD-36-51 had no afterburner. Airframe showing deflected rudder and no horizontal tailplane. on the day before it crashed. The aircraft's planform and canards are clearly shown. The aircraft was assembled from parts machined from large slabs, many over long and wide. While at the time, this approach was heralded as an advanced feature of the design, it turned out that finished parts contained defects which had not been detected in the raw material. Cracks formed at the defects at load levels below that which the part was expected to withstand. Once a crack started to grow, it spread quickly over many metres, with no crack-arresting design feature to stop it. The problem, discovered in 1976, may have been known prior to this testing; a large crack was discovered in the airframe of the prototype Tu-144 (aircraft 68001) during a stopover in Warsaw following its appearance at the 1971 Paris Air Show. Polish sources say the crack was discovered after the aircraft made an emergency landing due to the failure of both left-hand engines; however, an Aeroflot spokesperson denied the damage and disputed the circumstances of the landing. Later the same year, a test airframe was subjected to a test simulating the temperatures and pressures occurring during a flight. High skin temperatures of were caused by kinetic heating when the boundary layer air reached during cruise. The Tu-144 was placed in an environmental chamber and heated to simulate the skin getting hot quickly, during acceleration to cruising speed, while the underlying structure took a while to reach its equilibrium temperature. This thermal effect caused internal stresses and the situation was reversed while slowing down and descending. The pressure in the cabin, which caused additional stresses, was changed at the same time as the skin heating to simulate climbing to cruise altitude and then descending. Repeatedly cycling the temperature and pressure, as happened with the aircraft in service, caused fatigue damage and the airframe failed in a similar way to that of the TsAGI load testing. the Tu-144 design allowed a higher incidence of defects in the alloy structure, leading to the fatal in-air breakup of the aircraft in the 1973 Paris Air Show Tu-144 crash. This conclusion was supported by some of the designers involved in the aircraft's development. Vadim Razumikhin wrote that the load factor experienced by the plane at the moment of the break-up was less than the design limit. If the stress tests had been conducted earlier, the disaster may have been averted. Eventually, the airframe was strengthened and the control system was modified to prevent overstressing the aircraft. ==Flight testing==

Tu-144 suffered from a rush in the design process to the detriment of thoroughness and quality. According to Concorde technical flight manager Brian Calvert, "the rush to get [Tu-144] airborne exacted a heavy penalty later". Concorde's first flight was originally scheduled for February 1968, but was pushed back several times until March 1969 in order to iron out problems and test components more thoroughly. The rush is apparent even in outward timing: the 1963 government decree launching the Tu-144 programme defined that the Tu-144 should fly in 1968; it first flew on the last day of 1968 (31 December) to fulfill government goals set five years earlier. ==Production==

Sixteen airworthy Tu-144 airplanes were built: • the prototype Tu-144, registration number 68001 • a pre-production Tu-144, number 77101 • nine production Tu-144S, numbers 77102 to 77110 • five Tu-144D models, numbers 77111 to 77115. Although its last commercial passenger flight was in 1978, production of the Tu-144 did not cease until 1983, when construction of the final airframe was stopped and left partially complete. The last production aircraft, Tu-144D number 77116, was not completed and was left derelict for many years on Voronezh East airfield. There was at least one ground test airframe for static testing in parallel with the development of prototype 68001. ==Operational history==

Entry into service The introduction of the Tu-144 into passenger service was timed to the 60th anniversary of the Communist revolution, as was duly noted in Soviet officials' speeches delivered at the airport before the inaugural flight – whether the aircraft was actually ready for passenger service was deemed of secondary importance. Even the outward details of the inaugural Tu-144 flight betrayed the haste of its introduction into service: several ceiling panels were ajar, service trays stuck, window shades dropped without being pulled, reading lights did not work, not all toilets worked and a broken ramp delayed departure half an hour. On arrival to Alma-Ata, the Tu-144 was towed back and forth for 25 minutes to align it correctly with the exit ramp. Flight testing time logged on the prototype (68001) was 180 hours; flight testing time until the completion of state acceptance tests was 1509 hours, followed with 835 hours of flight time of service tests until the commencement of passenger service. The Tu-144S went into service on 26 December 1975, flying mail and freight between Moscow and Alma-Ata in preparation for passenger services, which commenced on 1 November 1977. The type certificate was issued by the USSR Gosaviaregister on 29 October 1977. The passenger service ran a semi-scheduled service until the first Tu-144D experienced an in-flight failure during a pre-delivery test flight, crash-landing on 23 May 1978 with two crew fatalities. The Tu-144's 55th and last scheduled passenger flight occurred on 1 June 1978. An Aeroflot freight-only service recommenced using the new production variant Tu-144D ("D" for ''Dal'nyaya'' – "long range") aircraft on 23 June 1979, including longer routes from Moscow to Khabarovsk made possible by the more efficient Kolesov RD-36-51 turbojet engines, which also increased the maximum cruising speed to Mach 2.15. There were only 103 scheduled flights before the Tu-144 was removed from commercial service. Early flights During 102 flights and 181 hours of freight and passenger flight time, the Tu-144S suffered more than 226 failures; 80 of them occurred in flight and 80 of them were severe enough to affect the flight schedule. The most frequent sources of trouble were the flight instruments, navigation gear, radios, and autopilot. After the inaugural flight, two subsequent flights during the next two weeks were cancelled and the third flight rescheduled. The official reason given by Aeroflot for cancellation was bad weather at Alma-Ata; however when the journalist called the Aeroflot office in Alma-Ata about local weather, the office said that the weather there was perfect and one aircraft had already arrived that morning. Subsequent and significant documented Tu-144 failures included insufficient cabin pressurisation in flight on 27 December 1977, a landing gear switch fault on 29 January 1978 that indicated that the gear was lowered when it was in fact retracted, and engine-exhaust duct overheating causing the flight to be aborted and returned to the takeoff airport on 14 March 1978. Additionally, a metal fatigue problem was discovered in the tip of the aircraft's vertical stabilizer; this was mitigated by adding a titanium doubler plate. Aleksey Tupolev, Tu-144 chief designer, and two USSR vice-ministers (of aviation industry and of civil aviation) had to be personally present at Domodedovo airport before each scheduled Tu-144 departure to review the condition of the aircraft and make a joint decision on whether it could be released into flight. Subsequently, flight cancellations became less common, as several Tu-144s were docked at Moscow's Domodedovo International Airport. Incident on 25 January 1978 Tu-144 pilot Aleksandr Larin remembers a troublesome flight around 25 January 1978. The flight with passengers suffered the failure of 22 to 24 onboard systems. Seven to eight systems failed before takeoff, but given the large number of foreign TV and radio journalists and also other foreign notables aboard the flight, it was decided to proceed with the flight to avoid the embarrassment of cancellation. After takeoff, failures continued to multiply. While the aircraft was supersonic en route to the destination airport, Tupolev bureau's crisis centre predicted that the front and left landing gear would not extend and that the aircraft would have to land on the right gear alone, at a landing speed of over . Due to expected political fallout, Soviet leader Leonid Brezhnev was personally notified of what was going on in the air. With the accumulated failures, an alarm siren went off immediately after takeoff, with sound and volume similar to that of a civil defence warning. The crew could not figure a way to switch it off so the siren stayed on throughout the remaining 75 minutes of the flight. Eventually, the captain ordered the navigator to borrow a pillow from the passengers and stuff it inside the siren's horn. After all the suspense, all landing gear extended and the aircraft landed. In 1995, Tu-144D No. 77114 (with only 82.5 hours of flight time) was taken out of storage and after extensive modification at a cost of US$350million, designated the Tu-144LL (where LL is a Russian abbreviation for Flying Laboratory, , Letayushchaya Laboratoriya). The aircraft made 27 flights in Russia during 1996 and 1997. In 2003, after the retirement of Concorde, there was renewed interest from several wealthy individuals who wanted to use the Tu-144LL for a transatlantic record attempt, despite the high cost of a flight readiness overhaul even if military authorities would authorize the use of NK-321 engines outside Russian Federation airspace. ==Reasons for failure and cancellation==

Limited routes Only one commercial route was ever used, an approximately route from Moscow to Alma-Ata (now Almaty), and flights were limited to one a week, despite there being eight Tu-144S certified aircraft available and a number of other routes suitable for supersonic flights, suggesting that the Aeroflot decision-makers had little confidence in the Tu-144 commercial viability when passenger service began in 1977. Compressor disc and other failures On 31 August 1980, Tu-144D (77113) suffered an uncontained compressor disc failure in supersonic flight which damaged part of the airframe structure and systems. The crew was able to perform an emergency landing at Engels-2 strategic bomber base. On 12 November 1981, a Tu-144D's RD-36-51 engine was destroyed during bench tests, leading to a temporary suspension of all Tu-144D flights. Economic inefficiency Global trends facilitated the transition of jet transportation from a luxury available only to the elite, to a widespread form of mass transportation. Although the 1973 oil crisis did not directly impact decision-making processes within the Soviet Union, the expansion of Soviet air travel in the late 1970s made the supply of aviation fuel a growth constraint, and it was obvious that potential Western buyers were heavily dissuaded by high fuel prices. By the late 1970s, Soviet promotional efforts shifted to the Ilyushin Il-86, a more economically efficient jumbo jet that went on to become the country's flagship airliner. Moon notes that in 1976, Aeroflot was promoting the Il-86 over the Tu-144, despite the latter's incipient and long-awaited entry into service. G.A. Cheryomukhin, an aerodynamics engineer who took part in the design and certification of Tu-144, wrote that the Ministry of Civil Aviation was concerned that the continuation and expansion of the SST's operation would have forced the Ministry to make significant long-term investments. Moon concluded that economic efficiency alone would not have doomed the Tu-144 altogether; continuation of token flights for reasons of political prestige would have been possible, if only the aircraft itself would have allowed for it, but it did not. The Tu-144 was to a large extent intended to be, and trumpeted as, a symbol of Soviet technological prestige and superiority. Tupolev design bureau and rivalry with Ilyushin Fridlyander and Moon point out that by the early 1970s, Tupolev's bureau had to work on other projects, including the Tu-154 and Tu-204 passenger aircraft, and the Tu-22M and Tu-160 bombers. Despite large and high-priority resource investment in the Tu-144 development programme and the fact that a large part of the whole Soviet R&D infrastructure was subordinated to the Tu-144 project, parallel project development overwhelmed the bureau causing it to lose focus and make design errors. Alexander Poukhov, one of the Tu-144 design engineers who subsequently rose to be one of the bureau's senior designers, estimated in 1998 that the Tu-144 project was 10–15 years beyond the USSR's capabilities at that time. Moon suggests that Tupolev's difficulties in developing the Tu-144, together with a need to prioritize bomber development, prompted Soviet leaders to shift airliner development to the rival Ilyushin design bureau, which had recently introduced the successful Il-76 military transport and was developing the Il-86 to move much larger numbers of passengers at a much lower per-seat cost than the Tu-144. Moon contrasts the Ilyushin bureau's careful advance research into operating costs and its marketing surveys of Aeroflot customers with the "technocratic futurism" embodied by the Tu-144, suggesting that Soviet leaders recognized that the Il-86 better addressed real-world transportation needs in the Soviet Union and elsewhere. ==Cessation of Tu-144D production==

The decision to cease Tu-144D production was issued on 7 January 1982, followed by a USSR government decree dated 1 July 1983 to cease the whole Tu-144 programme and to use produced Tu-144 aircraft as flying laboratories. The rushed introduction to service of poorly tested aircraft happened previously with another Tupolev project that had high political visibility and prestige: the Tu-104 passenger jet-liner was the first successful Soviet passenger jet in service. In a decision-making similar to the Tu-144-story, the Soviet government introduced the Tu-104 into passenger service before satisfactory stability and controllability had been achieved. During high-altitude and high-speed flight the aircraft was prone to longitudinal instability, and also at high altitudes, it had a narrow range of angle of attack separating the aircraft from stalls known as coffin corner. These problems created the preconditions for spin dives, that happened twice before the Tu-104 was eventually properly tested and the problem was resolved. Personal factors , a notable Soviet aircraft designer, considered the primary reason for ending the Soviet Supersonic Transport project to be the personal factor—the role of the Chief Designer, who failed to show due courage and defend his Bureau's brainchild following the tragic event near Yegoryevsk. "Cowardice and progress are incompatible," Selyakov sternly summarized. G.A. Cheryomukhin identified several major "blows" to the Tu-144 project. The first three were the death of Andrei Tupolev in 1972, the disaster at the Air Show in 1973, and the death of the active and authoritative Minister of the USSR's Aviation Industry (1907–1977). Dementyev had been at the helm of the domestic aviation industry for many years and was one of the champions of the SST program. The fourth blow came with Aleksey Tupolev's direction on 30 May 1978, to cancel the SST flight and temporarily halt aircraft operations. Cheryomukhin bitterly noted, "...our own leader – A.A. Tupolev – personally stopped the operation of the Tu-144, depriving the world of a source of evidence of the rationality of supersonic flight over land..." ==After project cancellation==

After ceasing the Tu-144 programme, Tu-144D No. 77114 (aircraft 101 or 08-2) carried out test flights between the 13–20 July 1983 to establish 13 world records registered with the Fédération Aéronautique Internationale (FAI). These records established an altitude of with a range of loads up to 30 tonnes, and a sustained speed of over a closed circuit of up to with similar loads. To put the numbers in perspective, Concorde's service ceiling under a typical Transatlantic flight payload of 10 tonnes was , and this is higher than the record set by the Tu-144D. According to unverified sources, during a 26 March 1974 test flight a Concorde reached its maximum speed ever of (Mach 2.23) at an altitude of , and during subsequent test flights reached a maximum altitude of . Concorde was originally designed for cruising speeds up to Mach 2.2, but its regular service speed was limited to Mach 2.02 to extend airframe life. One of Tupolev's web site pages states that "TU-144 and TU-160 aircraft operation has demonstrated expediency of limitation of cruise supersonic speed of M=2.0 to provide structure service life and to limit cruising altitude". ==Variants==

• Tu-144 – (izdeliye 044 – article 044) The sole prototype Tu-144 aircraft Over the course of the Tu-144 project, the Tupolev bureau created designs of a number of military versions of Tu-144 but none were ever built. In the early 1970s, Tupolev was developing the Tu-144R intended to carry and air-launch up to three solid-fueled ICBMs. The launch was to be performed from within Soviet air space, with the aircraft accelerating to its maximum speed before releasing the missiles. The original design was based on the Tu-144S, but later changed to be derived from the Tu-144D. Another version of the design was to carry air-launched long-range cruise missiles similar to the Kh-55. The study of this version envisioned the use of liquid hydrogen for the afterburners. In the late 1970s, Tupolev contemplated the development of a long-range heavy interceptor (DP-2) based on the Tu-144D also able to escort bombers on long-range missions. Later this project evolved into an aircraft for electronic countermeasures (ECM) to suppress enemy radars and facilitate bomber's penetration through enemy air defenses (Tu-144PP). In the early 1980s this functionality was supplanted with theatre and strategic reconnaissance (Tu-144PR). The dimmer civil prospects for Tu-144 were becoming apparent the more Tupolev tried to "sell" the aircraft to the military. One of the last attempts to sell a military version of the Tu-144 was the Tu-144MR, a project for a long-range reconnaissance aircraft for the Soviet Navy intended to provide targeting information to the Navy's ships and submarines on sea and oceanic theaters of operations. Another proposed navy version was to have a strike capability (two Kh-45 air-to-surface cruise missiles), along with a reconnaissance function. The military was unreceptive to Tupolev's approaches. Vasily Reshetnikov, the commander of Soviet Long-Range Aviation and subsequently, a vice-commander of the Soviet Air Force, remembers how, in 1972, he was dismayed by Tupolev's attempts to offer for military use the aircraft that "fell short of its performance target, was beset by reliability problems, fuel-thirsty and difficult to operate". Reshetnikov goes on to remember: The development and construction of the supersonic airliner, the future Tu-144, was included in the five-year plan and was under the auspices of the influential D.F. Ustinov (then Soviet minister of defence and confidant of Brezhnev, who represented interests of defence industries lobby in opposition to the military) who regarded this mission as a personal responsibility – not so much to his country and people as to "dear Leonid Il'ych" (Brezhnev) whom he literally worshipped, sometimes to the point of shamelessness... Yet the supersonic passenger jet was apparently not making headway and, to the dismay of its curator, it looked as though Brezhnev might be disappointed. It was then that Dmitry Fedorovich (Ustinov) jumped at someone's idea to foist Aeroflot's "bride in search of a wedding" on the military. After it had been rejected in bomber guise, Ustinov used the Military Industrial Commission (one of the most influential Soviet government bodies) to promote the aircraft to the Strategic Aviation as a reconnaissance or ECM platform, or both. It was clear to me that these aircraft could not possibly work in concert with any bomber or missile carrier formation; likewise I could not imagine them operating solo as "Flying Dutchmen" in a war scenario, therefore I resolutely turned down the offer. Naval Aviation Commander Aleksandr Alekseyevich Mironenko, followed suit: Ustinov could not be put off that easily. He managed to persuade the Navy C-in-C (admiral) S.G. Gorshkov who agreed to accept the Tu-144 for Naval Aviation service as a long-range reconnaissance aircraft without consulting anyone on the matter. Mironenko rebelled against this decision, but the commander-in-chief would not hear of heed – the issue is decided, period. On learning of this I was extremely alarmed: if Mironenko had been pressured into taking the Tu-144, this meant I was going to be next. I made a phone call to Aleksandr Alekseyevich, urging him to take radical measures; I needn't have called because even without my urging Mironenko was giving his C-in-C a hard time. Finally Ustinov got wind of the mutiny and summoned Mironenko to his office. They had a long and heated discussion but eventually Mironenko succeeded in proving that Ustinov's ideas were unfounded. That was the last time we heard of Tu-144. ==Operators==

; • Ministry of Aviation Industry • Aeroflot Soviet Airlines ; • NASA ==Aircraft on display==

museum , Germany While several Tu-144s were donated to museums in Moscow Monino, Samara and Ulyanovsk, at least two Tu-144D remained in open storage in Moscow Zhukovsky. As of June 2010, two aircraft (tail numbers СССР-77114 and СССР-77115) are located outdoors at Gromov Flight Research Institute, Zhukovsky (at coordinates and ). Previously, they were displayed at MAKS Airshows. Tail number 77115 was bought in 2005 by the Heros Club of Zhukovsky and still on display at MAKS as of 2019. In 2019, tail number 77114 was repainted in Aeroflot livery and put on display in front of the Gromov Flight Research institute main gate. A Tu-144S, registration СССР-77106, is on display at Central Air Force Museum of Russia in Monino. Its maiden flight was on 4 March 1975, the final one on 29 February 1980. The aircraft was used to assess the effectiveness of the air-conditioning systems and to solve some problems on the fuel system. It can be considered the first production aircraft, being the first to be equipped for commercial use and delivered to Aeroflot. The first operational flight was on 26 December 1975 between Moscow and Alma-Ata carrying cargo and mail. Another Tu-144, tail number СССР-77107, is on open display in Kazan and located at . The aircraft was constructed in 1975 and was a production model intended for passenger use. However, it was only used during test flights. On 29 March 1976 it made its last flight to Kazan. This aircraft was put on sale on eBay in 2017. TU-144S, tail number СССР-77108, is on display in the museum of Samara State Aerospace University (). It made its maiden flight on 12 December 1975, and its final flight on 27 August 1987. Development works on navigation system were made in this aircraft as well as flight-director approach. TU-144S, tail number СССР-77110, is on display at the Ulyanovsk Aircraft Museum in Ulyanovsk. Maiden flight occurred on 14 February 1977, the final Flight on 1 June 1984. This aircraft was the second of the two aircraft used for regular passengers' flights on Moscow – Alma-Ata route. In 1977 it flew to Paris to take part in the XXXII Paris Air Show at Le Bourget Airport. This was the last appearance of a Tu-144 in West Europe. СССР-77110 was the last aircraft produced of the model Tu-144S, powered with Kuznetsov NK-144A engines. In the first half of 2008 the cabin was open for visits and between August and September was restored and painted in the original Aeroflot livery. The only Tu-144 on display outside the former Soviet Union, tail number СССР-77112, was acquired by the Auto & Technikmuseum Sinsheim in Germany, where it was shipped – not flown – in 2001 and where it now stands, in its original Aeroflot livery, on display next to an Air France Concorde. As of 2017, the Technikmuseum Sinsheim remains the only museum in the world where the Tu-144 and Concorde are on display together. ==Accidents==

Paris Air Show crash At the Paris Air Show on 3 June 1973, the development programme of the Tu-144 suffered severely when the first Tu-144S production airliner (reg 77102) crashed. At the end of the officially approved demonstration flight, which was an exact repeat of the previous day's display, instead of landing as expected, the aircraft entered a very steep climb before making a violent downwards manoeuvre. for the crash was that the Tu-144 tried to avoid a French Mirage chase-plane that was attempting to photograph its canards, which were very advanced for the time, and that the French and Soviet governments colluded with each other to cover up such details. The flight of the Mirage was denied in the original French report of the incident, perhaps because it was engaged in industrial espionage. More recent reports have admitted the existence of the Mirage (and the fact that the Soviet crew was not told about the Mirage's flight), though not its role in the crash. The official press release did state: "though the inquiry established that there was no real risk of collision between the two aircraft, the Soviet pilot was likely to have been surprised". On impact, the nose cone collapsed under the fuselage, penetrating the compartment in which two flight engineers were seated, killing both. It was later determined that, 27 minutes prior to the ignition, a fuel line had ruptured, causing eight tons of fuel to leak into several compartments on the right wing. The fuel readings were judged incorrect by the flight engineers and thus were not reported to the commander. In addition to the two flight engineers killed on impact, six other crewmembers were injured. The Tu-144 was withdrawn from passenger service soon afterward, though a 2019 post-mortem by CNN reported that it was already "on its way out" before then. ==Specifications (Tu-144D)==