CFM International's CFM56-5B engine equipped with the double annular combustor (DAC) has been certified by the French Direction Generale de l'Aviation Civile on the Airbus Industrie A321 aircraft. The engine will enter service on the A321 later this month with Swissair, making it the first commercial aircraft engine with a double annular, low NOx (oxides of nitrogen) combustor to enter service.
CFM International is a 50/50 joint company of General Electric of the United States and Snecma (Safran Group) of France.
Engine certification on the Airbus A321 is the culmination of an extensive three-month flight test program which spanned more than 45 flight hours and validated the engine's overall operability characteristics.
Swissair, along with Austrian Airlines, is the launch customer of the CFM56-5B DAC-powered A321. The two airlines provided the initial impetus to incorporate DAC technology into the CFM56 family and have been an integral part of the development process. Citing overall reliability and operability as their top priorities, Swissair and Austrian worked with CFMI on concept and design reviews to ensure that the engine meets existing, as well as projected, regulatory requirements.
On a typical flight cycle for Swissair, the DAC engine will provide a reduction in NOx emissions of more than 45 percent compared to the CFM56-5B equipped with a single annular combustor (SAC). In addition, the engine is virtually smokeless.
CFMI is continuing development of low operating cost and low emission technology that brings the greatest value to the customer. Future, near-term developments will focus on the combustor cooling system, fuel nozzles, and control systems, with a target of achieving additional emissions reduction below current -5B DAC levels. The fuel nozzle and control system will be certified in September of this year, while the combustor cooling system is scheduled for certification in 1996. The DAC engine, which was certified at 27,000, 30,000 and 31,000 pounds takeoff thrust in mid-1994, is totally interchangeable with the SAC engine; thus, A319/A320/A321 customers have the option of specifying either combustor configuration for their -5B engines.