Francesca Landini, David Shepardson, and Tim Hepher

(Reuters) – An Italian subcontractor is at the center of recent snags on Boeing’s 787 Dreamliner (NYSE) (NYSE). He worked for a wide range of aerospace companies, including Spirit AeroSystems(NYSE:), industry sources claim.

Boeing and the regulators stated earlier that some parts of 787’s jetliner were made incorrectly over the last three years. Manufacturing Process Specification (MPS) supplied them indirectly as a subcontractor to Leonardo.

According to a letter Reuters saw, Boeing notified Spirit AeroSystems of possible issues with MPS parts in March and requested it use other suppliers to continue its audit of the Italian business.

Spirit, based in Wichita, was also requested to track any MPS components it used from 2017 to 2017. Spirit would then be deemed “suspect not conforming,” which means they would need to undergo further inspections.

Boeing stated that it had decided, “Out of an excess of caution as Boeing continues testing and evaluations,” to make all MPS products suspect.

Spirit and Boeing did not immediately respond to the correspondence. Boeing earlier stated that problems with 787 Dreamliners in service did not cause any immediate safety concerns.

Brindisi (based in Italy) was not available for comments when emailed and phone calls were made.

According to the Airbus website, MPS also qualifies as a supplier.

When asked if it had used parts in recent work by MPS, a spokesperson from the European firm did not immediately respond.