This variant of the P-3, the NP-3D carries an airborne phased array radar in the extension just forward of the vertical stabilizer.
Airplanes - Military - Parked - Utility
Because the "Billboard" phased array radar cannot see to the front or the rear of the aircraft, this installation is clearly intended to be used in a cooperative operation where other aircraft and radars form an interdiction line, and the threat is known to come from the direction the phased array is directed towards.
Typical range missions include radar/visual safety surveillance, telemetry data collection and retransmissions, high resolution optical collections, and general fleet support. These particular Orions have upgraded engines, the more powerful Allison T56-1-14, which gives them an incredible mission endurance of 12 hours.