The last of the true McDonnell Douglas DC-9 derivatives before the purchase by Boeing, the MD-90 was to become the longest and most efficient of the MD-80 range, a new face for a 30 year old design that had to maintain a desperate fight against its ever more influential rivals.
The MD-90, like the MD-80 that preceded it, can be traced back to the original Douglas DC-9 of 1965, a short-range companion to the company’s first jet outing, the DC-8. The DC-9 was an all new design at the time, with two turbofan engines mounted at the rear of the fuselage, while the wings were positioned further towards the aft to compensate. It also included a T-Tail design to accommodate the engine position. The DC-9 was replaced in 1981 by its derivative known as the MD-81, which was originally built to be a longer version of the DC-9 but was instead made into its own model range. The MD-80 series gave rise to five variants, the MD-81, MD-82, MD-83, MD-87 and MD-88.
Development of the MD-90 began in 1983, and was originally considered to be a shorter
variant of the MD-80 series to fill the gap left by the DC-9. Eventually, the concept was evolved from a short MD-80 variant into a longer one, and also toyed with the idea of fitting the aircraft with the experimental Propfan engines, which combined the turbofan and turboprop technology to allow for the highest efficiency. However, the Propfan idea was eventually scrapped, and the MD-90 was chosen instead to feature IAE V2500 Turbofan engines, developed by Swiss engine manufacturer International Aero Engines for the upcoming Airbus A320 project. V2500’s were considered much more efficient than the conventional Pratt & Whitney engines placed onto previous MD-80’s, and are notable for having a much wider cross-section.
The project was officially launched on November 14th, 1989, with Delta Air Lines placing an order for 50 aircraft with an option for an extra 110. The final design resulted in a fuselage extension over the MD-88 (the latest model in the series) of 5 feet, but would include the highly advanced Electronic Flight Instrument System (EFIS) of the -88. The extended length of the fuselage allowed for a capacity of between 153 and 172 passengers, based on seating configurations. The MD-90, however, was not the longest of the DC-9 derivatives, being shorter than the MD-87 by 4ft, 9 inches. The V2500 engines, as mentioned, improved efficiency, quietness and power substantially over the previous P&W JT8D’s, becoming the first DC-9 variant to be fitted with a high-bypass turbofan
engine. Plans called for two versions of the MD-90, the MD-90-30 and the MD-90-30ER. The -30 featured a range of 2,400 miles, while the -30ER could fly up to 2,750 miles. Another variant, the MD-90-50, was considered as an even longer range version of the aircraft, with a possible range of over 3,000 miles, but was never put into production.
The aircraft made its first flight on February 22nd, 1993, and was delivered to Delta nearly 2 years later in February 1995. Production of the MD-90 took place at the same location as the other MD-80 series, the Long Beach factory in California. Many customers specified differing versions of the -90 throughout its production life, with Saudi Arabian Airlines having their 29 units fitted with full glass cockpits with avionics and an overhead display panel in similar fashion to the MD-11.
McDonnell Douglas also allowed construction of the aircraft in the People’s Republic of China, being done under the Trunkliner program. McDonnell Douglas and the China National Aero-Technology Import and Export Corporation (CATIC) entered into discussions in 1992 regarding the construction of 40 MD-82’s and 40 MD-90’s to be put to work on China’s many domestic routes. Continuing discussions between the two companies saw the number reduced to 20 in 1994, while the other 20 would be U.S. built. In late 1995, production of the Trunkliner aircraft, known as the MD-90T, commenced in a small factory in Beijing, with tools and parts were provided by MD. However,
negotiations between the two companies continued to see the deal deteriorate, and by the time production started, the contract had been reduced to only 20 MD-90’s. The deal eventually stalled in early 1996 following an investigation by the Commerce Department and the U.S. Government, with only 2 aircraft actually built. The entire deal was called off in 2000 following the merger of McDonnell Douglas into Boeing in 1997. Many of the tools donated by McDonnell Douglas, and much of the development and research gathered into making the MD-90, did live on in the form of the Comac ARJ21, which was launched in 2016 as China’s first regional jet. The external similarities between the two are a dead give away to the ARJ21’s MD-90 roots.
Regardless, production of U.S. versions was proceeding well, with the MD-90 seeing work with a varying degree of airlines from across the globe, including Delta Air Lines, Saudi Arabian Airlines, China Eastern, Reno Air, Scandanavian Airlines and Japan Airlines. However, the MD-90 was sadly not a major hit, being not a major improvement over the already successful MD-80 series, and with new versions of the Boeing 737 (the 737-800) and the Airbus A320 (specifically the A321) now entering the market, McDonnell Douglas’ influence on the aviation industry was comparatively obscure. While MD-80’s still sold in good numbers, the failure of both the MD-90 and the MD-11 wide-body airliner to be successful hits in the industry meant that the company was losing money.
While MD considered another variant of the MD-90, the longer MD-94X, the company
was merged into Boeing in 1997. The MD-90 was immediately removed from the product list as Boeing didn’t want internal competition between it and the 737. As such, many existing orders were cancelled as faith in both the aircraft and the MD company was lost. Delta Air Lines had initially desired to fill its 110 aircraft option, but cancelled the last 19 aircraft in favour of the Boeing 737-800. Saudi Arabian were the last to receive MD-90’s when production ended in 2000, following the dissolving of the McDonnell Douglas brand under Boeing. The DC-9 design would continue on however in the form of the Boeing 717 (MD-95), which Boeing had considered its own and therefore used it to help compliment the likes of the 737 in the market place. Only 116 MD-90’s were ever built, and today the 65 remaining in service are all owned by Delta Air Lines. Only 2 have been lost in accident damage, resulting in only 1 fatality, a true testament to the safety and reliability of these fantastic aircraft.
The MD-90 is sadly an often forgotten version of the DC-9 derivative family, and was essentially the last true McDonnell Douglas built before the company was absorbed. I personally always had a fondness for the MD-90, it seemed to encapsulate all the best parts of the MD-80 family in terms of styling and performance, but also with the innovative new glass cockpit and improved engines. While I like the later Boeing 717 more, the MD-90 holds a place in my heart for what it did and what it hoped to accomplish. They’re still brilliant, brilliant aircraft, and hopefully will see continued service with Delta well into the future.