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.

The Aircraft Accident Investigation Bureau (AAIB) report mentioned that the fuel switches, manufactured by Honeywell, could likely be faulty.