Pratt & Whitney’s planned engine deliveries for the full year remain unchanged despite a part failure that could hold up engine deliveries to the geared turbofan’s largest customer until April.
The engine manufacturer is “committed to producing nearly double its 2017 rate of 374 GTF family engines” in 2018, P&W says. “We will continue to work with Airbus to minimise the impact on our airline customers.”
The PW1100G version of the GTF family is one of two engine options on the Airbus A320neo.
On 9 February, the European Aviation Safety Agency issued an emergency airworthiness directive after preliminary findings indicated that the root cause of four recent engine shutdowns was a recent durability improvement to the aft hub knife edge seal in the high pressure compressor. Six days later, the US Federal Aviation Administration published the same warning.
Both notices identified a batch of nearly 100 engines that Pratt & Whitney had delivered to Airbus, including 43 already operating in service.
Airbus and P&W have submitted a mitigation plan to the regulatory authorities. If the latter approve, Airbus expects deliveries from P&W to resume in April.
The incident arose just as it seemed P&W had finally overcome early teething issues on the GTF family. In December, P&W began implementing fixes for two parts with durability issues, but neither involved the aft hub knife edge seal. Instead, P&W redesigned the combustor line and carbon air seal in the No. 3 bearing.
The latest problem follows a familiar theme with the GTF. P&W packed the engine with several advanced technologies, including a fan drive gear system, hybrid-metallic fan blades and a sophisticated cooling system for the turbine blades. Despite the industry’s experience with such technologies, the most innovative parts of the GTF have not raised complaints about performance, although P&W acknowledged struggling with the manufacturing yields for the hybrid metallic blades.
Instead, the GTF has been bedeviled in airline operations by durability shortfalls and failures of fairly common parts, such as combustor liners and seals.