A new and dangerous era of air warfare and the A-6 Intruder

When Francis Gary Powers and his U-2 spy plane was shot down over the Soviet Union on May 1, 1960, a new and dangerous era in air warfare was begun. The S-75 Davina (Da-vee-nah) or as NATO calls it "The S-2 Guideline" was the first effective surface to air missile capable of shooting down high flying heavy bombers like the U.S. B-52. The appearance of such an effective weapon in the Soviet/Warsaw Pact arsenal overnight; negated the airborne component of the United States strategic nuclear triad (Missiles, Bombers and Missile carrying submarines) and would prove its deadly effectiveness beginning in 1966 in the jungles of Southeast Asia.

When Grumman Aircraft Company began development of their Y-2F aircraft in the mid-1950's, which would eventually become the A-6 Intruder in 1960. They were seeking to answer two priority requests of the United States Navy...

1. That the aircraft be fully capable of operating at all hours of the day and in all adverse weather conditions.

2. That the aircraft be fully capable of flying at low altitudes and maintain a suitable degree of maneuverability for evasion and radar avoidance.

   

It was a complex technical challenge in an era where computers still took up massive amounts of spacing and only planes such as the B-52 possessed the ample space to support what was considered that latest state of the art technology. The then Y-2F had to possess both a reliable method of measuring and displaying the ground changes below the aircraft as well as provide the pilot with a simplistic way to navigate at low altitudes and in miserable weather or pitch black darkness.

The answer was two fold. One was a vertical shooting radar altimeter which shot then captured a radio wave pulse from a transmitter/receiver transducer that was placed on the belly of the aircraft. The A-6 had two of these units, one under the port side intake and one on the tail behind the tail hook.

The other answer was the first solid state digital presentation computer tied to an aircraft radar system. Known as the DIANE (Digital Integrated Attack/Navigation Equipment) this computer turned incoming radar signals into a visual horizontal presentation of the outside world. The DIANE was the worlds first TIRCOM (Terrain Immediate Repetition Computer) navigation and guidance system for any airborne aircraft.

The DIANE presentation screen.

DIANE allowed the Intruder to fly "NAP" (Nape) a common pilots slang for "Nuts Above the Palm Trees!" and though the screen showed in only two colors, various shades of green and black, the presentation could tell the pilot both the altitudes of features but their various grades and inclines. DANE gave the pilot steering information to the target, detection of various threats and was designed to allow for both manual and auto delivery of weapons upon targets.

The A-6 Intruder lived best at low altitudes. The majority of A-6 missions during the Vietnam War were conducted at night, in miserable conditions at tree top level which negated the effectiveness of the North Vietnamese SAM defense systems. The Intruder would scream in at 500 feet under the cover of the traditional Vietnamese monsoon season to deliver a common mix of Mark 82 Snake eyes and Rock-eye cluster bombs upon enemy positions, weapons concentrations and supply routes. Few Intruders were shot down by SAM's with the majority taken out by that lucky shot from a Vietnamese rifle or machine gun.

In the end...the Intruders ability to carry out low level attacks made it one of the aircraft not to lose substantial numbers during the Vietnam War.