IMPACT OF FDTL NORMS IN AIRLINE FLEET SCHEDULING AND CREW ROSTERING: A CASE STUDY ON INDIGO'S 2025 INCIDENT

The 2025 revisions to India’s Flight Duty Time Limitation (FDTL) norms—enacted by the Directorate General of Civil
Aviation (DGCA) and aligned with ICAO standards—imposed a structural shock on lean airline operations. Key provisions capped
night Flight Duty Periods (FDPs) at 10 hours, extended weekly rest to 48 hours at the home base, reduced consecutive night landings
from six to two, and mandated quarterly Fatigue Risk Management System (FRMS) reporting. IndiGo, operating 1,862 daily flights
with near-zero crew buffers, was acutely exposed: Phase 2 enforcement triggered over 2,000 cancellations in December 2025, a collapse
in on-time performance from 90.2% to 8.5%, and losses exceeding ₹5 billion. This paper analyses the cascading failure through the
lenses of crew scheduling optimisation, comparative regulatory frameworks (DGCA, FAA, EASA), pilot mental health and fatigue
science, and evidence-based scenario modelling. Resilient FDTL compliance requires a triad of investments: AI-enabled crew
management, robust reserve pools, and a just safety culture that normalises fatigue reporting.