The PNS Mehran Base attack occurred in:

The attack on the PNS Mehran Base occurred in 2011. This significant terrorist incident took place on May 22, 2011, when heavily armed militants, identified as members of Tehrik-i-Taliban Pakistan (TTP), infiltrated the Pakistan Navy's primary air station in Karachi. The attack resulted in the destruction of two P-3C Orion surveillance aircraft and a prolonged firefight with security forces, causing casualties on both sides.

• Options 2000, 2012, and 2013 are incorrect. The specific date of the PNS Mehran attack is well-documented as occurring in 2011.

This event highlighted the persistent security challenges faced by Pakistan and led to increased scrutiny of military installation security.