Pratt & Whitney is poised to enter the crucial certification test phase of its PW1100G for the Airbus A320neo and is working around the clock to keep to schedule as it readies hardware for evaluation.

The Neo engine's entry into certification marks a key milestone for Pratt's busy development timetable for the geared-fan family, which was designed to take advantage of the experience gained on the parallel-engine programs for Bombardier's CSeries and Mitsubishi's Regional Jet (MRJ) in Japan. First flight of the PW1500G-powered CSeries was expected imminently at press time, and results from the development of the PW1500G have already been applied to the PW1100G, and vice versa.

A revised cooling design devised for the Neo engine as a result of discoveries made during testing in May will also now feature in production-standard powerplants for the CSeries, says Bob Saia, vice president of Commercial Development Programs. These cooling-flow revisions are now being tested on the fourth Block 1 PW1100G endurance engine, and are designed to counter thermal distress in the inlet guide vanes to the first stage of the high-pressure turbine, he adds. “The engine is configured to the Block 2 [certification] hot-section standard from a durability perspective, and now we are running cyclic endurance and triple-red-line [operational limits] testing,” which will pave the way as a pre-test for the actual 150-hr. test around nine months from now, Saia says.

The first certification engine is set to start testing in late October and will begin a process scheduled to run through June 2014. Delivery of the first engines to Toulouse to power the prototype Neo is set for late June or early July. Pratt remains confident that the process will be completed on time, based on progress achieved to date.

“We have fully validated the design and the engine looks really good,” Saia says. “We've done bird-impact, blade-release and containment tests in the lab. From the stress-testing perspective, we've done the low- and high-pressure-spool stress testing, so structurally the engine has been completed.”

A second flight-test campaign on the company's 747SP testbed is expected to start in mid-October to validate full-authority digital engine control software in preparation for a final set of aircraft-level control flight tests in the second quarter of 2014.

“So right now, we are holding certification schedule. The biggest challenge is getting the hardware in and installing all the unique instrumentation,” explains Saia. “But overall, the engine is running very well and, actually, in terms of core temperature, we're about where we want it be.” Fuel burn is a “few tenths of a percent” better than expected.

“Typically, the first engine we deliver to the customer is playing catch-up from what we learned in the test program. In this case, with this being the third engine, the quality and design is much improved,” he notes.