Airlines and passengers at San Francisco International Airport are experiencing widespread disruption as runway 28L undergoes 20 days of construction work. The runway was closed on 7 September so that a new base layer could be constructed and total airport capacity has been significantly affected as a result. San Francisco International Airport recently entered a period of major construction work which will see its busiest runway out of action for 20 days. As reported by Flight Global, the runway requires a new base layer. The base layer was previously “showing signs of fatigue cracking due to a large amount of aircraft activity”. The issues with the base layer of runway 28L were first detected in Spring 2017 whilst work to repave the top layer of the runway was ongoing.