A Selected Acquisition Report seen by Bloomberg says Pratt & Whitney had delivered F135 engines with quality deficiencies in turbine blades and electronic control systems.
By Rick Goodfriend [Public domain], via Wikimedia Commons
These deficiencies had forced maintenance personnel to remove suspect hardware from the operational fleet.
The same report said Pratt & Whitney “has taken action to improve quality surveillance within their manufacturing processes.”
A spokesman from the Joint Strike Fighter program office replied in an email that the engine manufacturer “has shown that they have made progress reducing the number of quality escapes.”