EC 225 clearing hurdles; certification slips to 2004

 - August 5, 2008, 7:00 AM

Eurocopter now hopes to obtain certification for its EC 225 by early next year instead of in the third quarter of this year, as previously stated. According to the Franco-German helicopter manufacturer, the civil EC 225 is planned to be certified before qualification of its military sister, the EC 725, both of which are upgraded variants of the AS 332L2 Super Puma.

Flight testing of both versions is under way at Eurocopter’s Marignane facility near Marseilles, France. Tests of the EC 225/725’s 2,400-shp Makila 2A engines are also well under way at Turboméca’s Toulouse test site, also in southern France.

The 24,200-pound-mtow EC 225 combines new engines, developing 13 percent more power than the Makila 1A2s they replace, with a five-blade main rotor and uprated gearbox. Other system improvements are intended to keep the basic Puma competitive against relative market newcomers such as the NH 90 and EH-101.

Eurocopter has not offered any explanation for the latest program delay, which rolled back the previously announced certification date almost a full year. At one time, Eurocopter and Turboméca were pointing to what each considered program slippages caused by the other. Turboméca cited what it considered gearbox problems on Eurocopter’s side, and Eurocopter blamed Turboméca for delays with the new engines.

Turboméca v-p of aero engines François Courtot did acknowledge “normal slippages” in his company’s development of the Makila 2As. Certification of the civil variant of the Makila 2A turboshaft has slipped from this December to February.

Plans call for the French civil aviation authority, the DGAC (direction générale de l’aviation civile), to certify the EC 225 first, with the UK’s CAA following a month later and the newly formed European Aviation Safety Agency (EASA) roughly 30 days after that.

The military version of the Makila 2A for the EC 725 is expected to gain preliminary qualification from its launch customer, the French air force, as soon as December. Turboméca cites special required capabilities for the military helicopter, such as the ability to run at emergency power for two hours without engine damage, as especially challenging hurdles to overcome. The French air force’s special operations command ordered 10 EC 725s last November. Deliveries to operational French air force units are scheduled to begin next March. In a tactical troop-transport role, the helicopter can carry 19 troops more than a 250 nm radius of action. In the combat search-and-rescue role, the EC 725 is able to rescue a downed crew at a radius of action of 280 nm.

Turboméca started certification testing for the Makila 2A early this year after a compressor redesign significantly delayed the program. The engine undergoing these final tests will be at mid-life (approximately 1,500 hours) and some blades and vanes will already have dents and scratches.

Its next 150 hours are supposed to represent the rest of its life by “accelerated aging.” This includes a number of cycles with high rotation speeds. The 150 hours will be spread over 15 days, with inspections after each testing period. Before the final tests, some 10 engines have undergone various trials, including water, hail, sand and detergent ingestion.

A major innovation on the Makila 2A is the turbine’s “blade shedding” capability, which is intended to protect the engine from overspeed. Above a given rotation speed, blades separate from the disk. Engineers had to demonstrate that the blades are contained within the engine case and eventually ejected at the rear of the engine.

TBO at certification is expected to be 3,500 hours, and Turboméca plans to extend it to 6,000 hours later. Experience on both the 2A and older, in-service versions should help in reaching the higher TBO.

The launch customer for the EC 225 is UK North Sea operator CHC Scotia, which plans to put the new helicopter into service next April. Certification of the EC 225 is a prerequisite for the qualification of its military sister, Eurocopter said. Development tests, including flight-envelope expansion, avionics integration and de-icing system validation, are “almost complete.”

Eurocopter plans by early next year to complete airframe endurance, fatigue and damage tolerance testing; avionics flight testing, with autopilot mode validation and coupling with the flight deck; and (beginning in November) flight-into-known-icing conditions.

Eurocopter is running, in parallel, civil certification work and military mission system qualification. Military systems to be qualified include missile countermeasures, machine gun, FLIRs and navigation and communication systems.