“Lean burn combustion results when temperature is uniform throughout the hot section—specifically in the combustor—rather than having hot spots, which will lead to peak stresses, cracks and wear,” he explains. “Much of the turbine maintenance is driven by the peak temperature versus the average temperature to which the part is subjected. If your combustor burns uniformly, it will last longer on wing. The GEnx uses this, as will the Leap, and it's proving to have a very big maintenance cost benefit.”
GE Aviation had 4,000 shop visits globally in 2013, and that is expected to increase in the low single-digit percentage range in the coming year, says Dwyer. The worldwide GE maintenance network totals 92 facilities, of which five are GE-owned and 19 are joint ventures. The GE-owned facilities handled about one-third of those shop visits. Of the 92, half work on the CFM family.
“At GE, our protocol is to develop repair processes on one engine, and apply them to others, where possible. The technology that is developed to repair a new engine will find its way to current-generation engines for upgrades during the overhaul process,” he says.
ICF SH&E's Brown agrees that as the OEMs develop new engines and manufacturing techniques, this protocol may benefit the repair programs they can develop for existing engines, and save on maintenance costs.
“Ultimately, the technology will reduce the number of parts in the engine, so there are potentially less parts to repair. But, it does raise some concern for non-OEM, independent MROs,” Brown adds. “As the latest technology is incorporated will these parts be repairable, or will they be so technologically complex and costly that only the OEM could repair them, or new parts have to be purchased from the OEM?”