Boeing shares fell around 8% in premarket trading on Monday after the FAA grounded dozens of 737 Max 9 planes. This was in response to an incident on Friday where a door plug blew out mid-flight on an Alaska Airlines Flight 1282, causing rapid depressurization. The FAA order requires urgent inspections of around 171 Max 9 aircraft operated by major carriers in the US. The incident brings renewed scrutiny onto Boeing from regulators as it tries to ramp up 737 Max production and rebound from two fatal crashes, pandemic-related supply chain issues, and various quality defects.