The lede: When the FAA drops an Airworthiness Directive on a jet engine fleet, it isn't just a compliance memo — it's a federally mandated purchase order. On January 2, 2026, the FAA finalized an AD on GE Aerospace's GE90 engines (powering Boeing 777s) after powder-metal contamination was found in high-pressure turbine disks, forcing operators to swap parts on a fixed cycle-count schedule. Weeks later, the FAA issued a parallel AD on CFM International LEAP-1A engines, mandating FADEC/PHM software and hardware replacements, effective February 25, 2026. Each AD works the same way: the FAA sets a legally binding deadline, airlines have no choice but to comply, and the same handful of companies that built the engine are also the only ones certified to fix it. That's not a coincidence — it's the structure of the commercial engine business, and it turns every AD into a demand shock nobody has to sell.