India on Monday ordered its airlines to examine fuel switches on several Boeing models while South Korea ordered a similar measure on Tuesday, as scrutiny intensified of fuel switch locks at the centre of an investigation into a deadly Air India crash.

The report and India’s inspection order referred to an advisory from the Federal Aviation Administration in 2018 that recommended that carriers using Boeing models, including the 787, inspect the locking mechanism of the fuel control switches to ensure they could not be moved accidentally.

India’s Directorate General of Civil Aviation stated the directive would apply to Boeing 787 Dreamliners and select Boeing 737 variants and that airlines must complete inspections and submit their findings to the regulator by July 21.