FAA investigates after Boeing 737-800 part falls off on Southwest flight

• It comes as Boeing faces increased scrutiny over manufacturing and safety concerns involving its aircraft — though the model involved in the Denver incident dates from around 2015 and is an earlier generation than the 737 Max 9 jets that were temporarily grounded earlier this year following an Alaska Airlines mid-air door plug blowout.

Between the lines: Engine cowlings are designed to be accessible for maintenance by airlines, and the incident is unlikely to be related to Boeing's broader safety issues with new aircraft, per Axios' Andrew Freedman.

Zoom out: Southwest has 207 Boeing 737-800 aircraft and the average age of the airline's fleet is about 12 years, per an online company statement.

What they're saying: Southwest Airlines said in an emailed statement Sunday evening that its maintenance teams were reviewing the aircraft after Flight 3695 experienced a "mechanical issue."

• It apologized for inconveniencing affected passengers, who arrived in Houston on another plane about three hours behind schedule.
• A spokesperson for Boeing declined to comment on the matter and referred Axios to Southwest for information about their airplane and fleet operations.

Go deeper: Boeing paid Alaska Airlines $160M for losses after 737 Max grounding