It was a tense couple of months for Piper, but all 39 M600 single-engine turboprops that had been voluntarily grounded by the manufacturer in July have now returned to service after successfully passing wing-spar inspections, according to a report by Flight Global.
The FAA issued an airworthiness directive last month after Piper discovered cracking in the aft wing spar of a single M600 during final assembly. Piper said it was grounding the fleet and issuing a service bulletin requiring inspections of all M600 wing spars out of an “abundance of caution.” Piper blamed the issue on a single out-of-tolerance part produced by its wing spar supplier.
To ease any concerns M600 owners might have, Piper has extended the manufacturer's warranty for all wing-structure components from five to seven years, according to the published report.
The M600, a derivative of the Piper Meridian featuring an all-new wing, entered service in June 2016.