The following article was found in GUNSHIPS a pictorial History of Spooky,
Published by squadron/signal publications, pg. 53.

Lockheed AP-2H and OP-2E Neptune

During the 1966-67 period, the US Navy was keenly interested in development of an aircraft for use in the interdiction role along South Vietnam s road and water networks. Supplies were flowing into South Vietnam via the Mekong River, which flowed through Cambodia before passing through South Vietnam. Navy armored patrol boats and Black Pony OV-10s were doing a creditable job but another solution was needed, especially at night. With the Air force becoming very successful with the gunship concept, Navy planners decided to adapt some of the technology for their own use. They had an aircraft available, the P-2 Neptune series, which was being phased out in favor of the P-3 Orion, and this made the Neptune the obvious choice for conversion to the gunship configuration.

In 1967 four SP-2H aircraft were modified for the gunship role. These were field modified with multiple Miniguns mounted at various angles in the bomb bay which created a spray effect when fired. Very little is known about these very early conversions except that they were painted in several colors, one in overall black, one green, and two in overall grey.

The official program involving P-2 airframes was TRIM (Trails and Road Interdiction, Multisensor) using four production aircraft. The four aircraft were highly modified SP-2H airframes carrying a big fuselage ASW radome with the MAD boom on the tail being removed entirely. In place of the MAD boom a twin 20MM cannon-armed tail turret and tail gunners compartment was installed. The tail gunner used a Night Observation Scope (NOS) in place of the standard reflector gunsight. Where the ASW radome had been was a large radome housing an AN/APQ-92 search radar. A FLIR and LLLTV sensor was mounted in a large chin fairing under the nose. Side-Looking Airborne Radar, in a pod similar to that used on the OV-LB, was mounted aft of the wing trailing edge on both sides of the fuselage. Additional equipment included a Real Time IR sensor, an airborne Moving Target Indicator, DIANE (Digital Integrated Attack and Navigation Equipment), and a Black Crow truck ignition sensor. Much of this equipment would later be employed on the A-6C TRIM aircraft. All four AP-2Hs carried exactly the same equipment.

Armament was two forward-firing SUU-1 lA/lA Minigun pods, two Mk 82 500 lb GP Bombs, and two Mk 77 incendiary bombs; all being mounted under the wings just outboard of the reciprocating engines. In addition, later machines were fitted with an XM-149 40MM grenade launcher mounted in the former bomb bay. This was all in addition to the twin 20MM guns in the tail. Both the recip motors and the jets were extensively muffled after the aircraft were deployed to the war zone.

Deployment came in 1968 when the four AP-2Hs were assigned to Heavy Attack Squadron (VAH) 21 at Cam Rahn Bay. Between 1 September 1968 and 16 June 1969, the four aircraft flew over 200 missions, most being flown against road and river traffic in the ‘Parrots Beak area of the Mekong Delta, but some missions were flown against targets inside both Cambodia and Laos, as well as the Ho Chi Minh Trail. All four aircraft were returned to ConUS in 1969 at which time they were demodified and placed in storage at Davis-Monthan AFB. Only one example survived the cutting torch and now resides in the Pima County Air Museum in Tucson, Arizona.

OP-2Es were not really gunships, but they did work in conjunction with gunships — and they were armed. They began life as twelve standard SP-2E ASW aircraft. Prior to conversion to OP-2Es, all the aircraft were re-engined and brought up to SP-2H specifications. The twelve machines were then modified by the Naval Weapons Center into OP-2Es. Again the MAD boom and ASW radome were removed. In the tail of the aircraft was mounted an AN/ALE-29 Chaff Dispenser, and under the nose was mounted a large radome housing and AN/APQ-l3l radar. The main mission for the OP-2E crews was dropping sensors along the Ho Chi Minh Trail. For this they were fitted with multiple ejector racks just outboard of the recip engines. Additional sensors were carried within the bomb bay. If a target presented itself the OP-2E could attack with a pair of underwing mounted SUU hA/lA Minigun pods.

The twelve OP-2Es deployed to Southeast Asia and were assigned to Observation Squadron 67, VO-67, flying out of Nakhon Phanom AB in Thailand. The squadron was operational from 15 February 1967 until 1 July 1968. The sensors they spread up and down the Trail were all part of Project Igloo White, code name for the electronic warfare operations conducted along the Trail. Igloo White aircraft, like the OP-2Es, would drop small acoustic and seismic sensors along the Trail routes. The acoustic sensors, such as Spikebouy and Acoubouy, would remain in place, inactive, until the noise of a passing truck or tank would activate them. Seismic sensors, such as Adsid, were activated by a vehicle moving near the sensor. Once activated the sensor would transmit a signal to either an airborne relay station, such as a QU-22B drone or EC-121R, or to a gunship carrying beacon tracking radar. The information was then relayed to a ground readout facility where it was analyzed and a possible attack ordered for that sensor s area. Igloo White continued long after the OP-2Es departed Southeast Asia, with F-4Ds taking their place as sensor droppers. The OP-2Es then suffered the same fate as the AP-2Hs, ending their service lives in the desert sun awaiting the cutting torch.

Carrying the Navy s three-tone Grey scheme, this AP-2H is from Heavy Attack Squadron 21. The photo is taken ‘out-country as evidenced by the lack of armament and jet engine muffling. (Navy). - Webmaster's Note: This is VAH-21 A/C #1 BuNo.135620.