For one possibility see this thread:
“FAQ: The V1-VR Terrorist Runway Kill Zone (RKZ) Frequently Asked Questions”
“If any two engines on a large multi-engine jet can be disabled in the RKZ by a terrorist attack, the aircraft will not be able to gain enough altitude to return to the airport and will almost certainly crash. The availability of inexpensive, GPS-guided autonomous model aircraft and helicopters (drones and UAVs) that are capable of precisely targeting the runway path of each jet engine in the RKZ makes terrorist attacks increasingly probable.”
See tag line...