World’s oldest passenger 737-300 in operation turns 35

By Veljko Marinković

December 17, 1985, a cold day in Belgrade, after flying 12.000 kilometres from Seattle with two fuel stops in Canada and Shannon, the fourth Boeing 737-300 for JAT, registered YU-ANI (Boeing 737-3H9 MSN: 23416) touched down for the first time on the runway at Belgrade Airport. The day after, YU-ANI took off for the first time as JU350 to Frankfurt. After carrying more than three million passengers and 35 years later, YU-ANI is still in service and marking a historic milestone. YU-ANI holds the record for being the oldest passenger Boeing 737 series 300 still in regular, passenger service (excluding cargo and military VIP configuration versions). It was delivered to JAT Jugoslovenski Aerotransport, flew for its successors JAT Yugoslav Airlines and Jat Airways and is currently flying under Air Serbia’s charter brand - Aviolet. Over its lifespan, it has been leased to several carriers including Constellation International, Cameroon Airlines, Air Malta, Tunis Air, MAT and Air Ivoire.

YU-ANI in Zurich, June 1986

JAT used the aircraft in October 1986 for the inaugural flight and opening ceremony of the new airport in Niš. Thousands of locals gathered to greet the jet at their new airport. Locals joked that since Niš’s license plates are “NI”, JAT deployed the 737 which had the same last two letters on its plane registration. They concluded that even the plane had a Niš license plate. The first commercial revenue flight from the new airport in Niš was operated later that evening to and from Belgrade with the DC-9.

YU-ANI at the opening of Niš Airport

The story behind the Boeing 737-300 aircraft type at JAT dates back to 1984. The airline was seeking a new aircraft for its Euro-Mediterranean network, which would replace the DC-9 and B727 fleet. The oldest DC-9 at that time was fourteen years old, and the B727 was ten years old. They were second generation jets. Due to a volatile market, high fuel prices and competition, JAT reacted sooner than planned. The main goal was to find an aircraft type that would provide higher frequencies, not capacity, with lower costs. The decision was made to go with the Boeing 737-300, instead of the MD-80/81/82 (DC-9 super 80) which was already in use (Inex Adria had it in its fleet) and the Airbus A320 which was due to enter into service in 1988/1989. 

JAT's first 737-300, YU-AND, on the assembly line

It was a very risky decision. The Boeing 737-300 was entering into service at the end of 1984 and besides one British charter company, there were no orders for this aircraft type in Europe (six carriers in the world had orders at that time). That made it difficult to utilise the aircraft in terms of operations, maintenance, crew training etc. But the 733 had brought a host of new features and many aerodynamic, structural, cockpit and cabin improvements. Composite materials were used on all flight controls to reduce weight. The sole power plant was the GE and Snecma CFM-56-3, which was at the core of the Boeing 737-300 improvement and proved to be almost 20% more efficient than the JT8D used in earlier models. 

JAT became the first European operator to introduce the type into scheduled service and, at that time, it had at its disposal one of the most modern fleets in the world. It is important to note that JAT introduced its first jet-engine aircraft, the Caravelle SE-210, only three years after its maiden flight, similar to the McDonnell Douglas DC-9. The contract with the Boeing Company and JAT was signed on September 23, 1984, initially for the purchase of two 737-300 aircraft. The book price for the new 733 at that time was 23 million US dollars. At least 50% of the price was paid through the export of Yugoslav goods to the US and aircraft parts to Boeing. 

Prva Petoletka Trstenik produced parts for the Boeing 737-300 aircraft that included landing gear and braking system components. It became a Boeing certified part supplier in 1989. Utva Pančevo was also certified by Boeing, and produced machined and sheet metal parts, tools and assemblies (slats, wingtips and floor supports) for the Boeing 737 and Boeing 757 aircraft. Utva was also manufacturing parts and tools for Tupolev Tu-204 and Ilyusiin IL-114 aircraft, and later also for Airbus. Soko Mostar “Vazduhoplovsto” began its cooperation with Boeing back in 1980, producing 300 aircraft window frame assemblies for the 727 and 737. Later, during the 1980s, Soko also delivered cockpit doors, emergency exits and wing parts for the 737 family, as well as for the latest generation Boeing model - the 757.

JAT’s first Baby Boeing, which is how 747 pilots used to call the 737, landed in Belgrade with the registration YU-AND (MSN: 23329) on August 8, 1985. A day later, JAT deployed YU-AND on its first revenue service from Belgrade to Amman via Istanbul, replacing the Boeing 727. The first effects of the arrival of the brand new 733 were significant savings in terms of fuel consumption compared to the B727, seven tons less on a route such as this. Ten days later the second 733 arrived, YU-ANF.

Roll-out for YU-AND's first test flight, Seattle, July 1985

By mid-October, the 737s were achieving a utilisation rate of six hours per day on nine routes. YU-AND operated the first Boeing 737-300 service to London Heathrow from Belgrade on October 5, 1985, as JU210. Crew training for the introduction of the first pair of 737-300s involved twelve captains and twelve first officers, flying 100 hours under the supervision of Boeing instructors. A similar process was followed for the two additional -300s, ordered in March 1985.

The third and fourth Classic 737s were YU-ANH and -ANI. They had their first revenue flights in December 1985. In 1986 two more 737s arrived (YU-ANJ and ANL), while in November 1987 YU-ANK entered into service. Finally, the last two, YU-ANV and ANW, landed in Belgrade in 1988. By 1988, the average daily utilisation of the nine Boeing 737s was 8.16 hours. 

JAT's version of this airplane had a total 138 seats. In the front of the plane were 54 seats provided for passengers in Adriatic class and 84 for economy class passengers. Adriatic class was JAT’s special business class, a unique product in the skies above Europe and was introduced back in 1983. Both classes had more comfortable seating and the over-head compartment for hand luggage was larger than any other aircraft in JAT’s fleet. The cabin also featured a video broadcasting system for shorter films and safety demonstrations, as well as an eight-channel music system. Later, some of the Boeing 737s had a new business class with a 2-2 configuration in the first three rows, while some had blocked middle seats, and now, the remaining 737s are flying in all economy class layout (144 seats). 

It is interesting that JAT’s Boeing 737 was different than the others in -300 series because it did not have an EFIS cockpit (Electronic Flight Instrument System). Also, another interesting fact is that during the 1990s, JAT’s engineers and mechanics successfully dealt with corrosion on one part of the 737 wing, which was an unknown procedure at the time. Later, Boeing introduced this practice as a standard maintenance procedure for the entire family.

YU-ANI on final approach at Skiathos Airport, August 2008 (photo by Hristos Lachtaras)

According to JATs development plans, by 1995 the Boeing 737-300 should have counted 24 jets.. JAT had also analysed the need for a higher-capacity aircraft, in the event of increased demand, and considered replacing some of the -300 series with the larger -400 version, which had been announced by Boeing at the time. This would have meant that the B727 would be replaced (its final retirement was planned for 1995) both in terms of passenger capacity and, above all, in terms of paid cargo, where the 733 was significantly weaker than the 727. Also, by 1995 JAT was supposed to have 11 planes in the fleet for domestic and regional traffic (later it was decided that it would be ATR-72). 

In addition to its own 737-300 fleet, JAT leased several more Boeing 737s during over time. The longest-running among them was YU-AON Boeing 737-3Q4, followed by YU-AOU and YU-AOV (leased from Bulgaria Air). Also the larger version, Boeing 737-400 was part of the fleet during the 2000s (YU-AOO, YU-AOR, YU-AOS and YU-AOK). The airline exclusively deployed the aircraft on some routes, such as the Belgrade - Tivat - London - Tivat - Belgrade service in 2004. Also, JAT leased out, dominantly through dry leasing, its own fleet of Boeing 737-300s to other airlines across Europe, Africa, Middle East and even in Australia (in 1989 YU-AND and YU-ANJ flew for Australian Airlines). Furthermore, due to United Nations sanctions, YU-ANI was forcibly grounded and held at Istnabul Airport for eight years. It was returned to its home base in May 2000.

Aviolet operate by Air Serbia, YU-ANI, departing Brussels

Today, only two Boeing 737-300s (YU-ANI and ANK) are in use by Air Serbia’s charter brand Aviolet, flying predominantly on charter and leisure destinations, but it can also be seen at some major European airports on regular, scheduled services. The first Boeing 737, YU-AND, has been parked since February 2020 and is awaiting to be placed at the Museum of Aviation in Belgrade. After millions of passengers and kilometres flown, the future of the remaining 737s it is uncertain, especially today, when the aviation sector is in one of its most difficult periods. 

However, the Boeing 737-300 still brings emotions. For those of us who flew this plane for the first time in our lives, it's more than flying every time; for spotters it is a great opportunity to catch part of history; and also brings some kind emotions for those passengers who would expect a cabin in better condition. So, the 737-300 story, continues….