On a Saturday morning in May, 2020, Italian police officers caught two men pouring chemical waste into the sewers in the southern port city of Brindisi, near a small plane components factory.

Five years on, that routine pollution case has spiralled into a wide-ranging judicial investigation into how thousands of flawed titanium and aluminium parts manufactured in Italy ended up in nearly 500 Boeing 787 jets still in use.

The probe focuses on how tiny aero-part-maker Manufacturing Process Specification (MPS) allegedly defrauded clients by using cheaper and weaker metals to make floor fittings and other plane parts. Company executives deny the charge.

But the precarious chain of events that led detectives to the alleged scam, including the surprise pollution find, raises broader questions about the failure by the aerospace industry’s own voluntary audit system to detect sub-standard components.

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