DGCA issues urgent directive to Indian Boeing operators after AAIB’s AI 171 crash report. All 737, 747, 757, 767, 777, and 787 models must inspect engine fuel control switch locks by July 21. AAIB flagged non-compliance with FAA's 2018 advisory. FAA and Boeing now say the locks are safe. DGCA urges strict compliance for airworthiness.