Four P-2Hs were modified in 1966-67 by E-Systems to carry a TRIM (Trails & Roads Interdiction, Multisensor) package for night interdiction operations over the Mekong Delta with Heavy Attack Squadron Twenty-One (VAH-21). All ASW equipment was removed and specialized sensors fitted. The sensor package included AN/APQ-92 search radar, FLIR (forward-looking infra-red), LLLTV (low-light level television), SLAR (side-looking airborne radar), DIANE (Digital Integrated Attack and Navigation Equipment), and 'Black Crow' motor vehicle's engine ignition sensor. Armament consisted of twin 20 mm cannon in a tail turret and two minigun pods and four bombs beneath the wings. Some aircraft were also fitted with a 40 mm grenade launcher projecting below the bomb bay. Sound suppressing equipment was fitted on the two piston engines and two turbojets while "in country".

VAH-21 was disestablished on 16 June 1969 and all five Neptunes were returned to the U.S. Three gunships had most of their specialized equipment removed and were placed in storage at MASDC on 22 June 1969. Bureau Number 145902 was assigned to the Weapons System Directorate at the NATC until early November 1970, when it too was placed in storage. Number 135620 was spared the cutting torch and resides at the Pima County Air Museum in Arizona. Aircraft number ".5" served VP-42 before ending up at MASDC during November 1969.

Heavy Attack Squadron 21 Home Page


AP-2H Neptune Gunships of VAH-21
LP-2J Ski Birds of VX-6
RB-69A and P2V-7U ELINT Neptunes

"In the Shade of the Wing"
Ron Wheeler VP-23 1955-1958