Project Muddy Hill Marked Advent of
Air EO Reconnaissance in Combat
By ROBERT ZAFRAN
During the Vietnam War, the U.S. armed forces
experimented with a wide variety of cutting-edge
technologies to detect and interdict enemy troop
movements in the jungle-covered terrain of Southeast
Asia. One such effort was Project Muddy Hill, formed
in early 1966 as a research and development project at
the Naval Air Test Center in Patuxent River, Md.
Co-funded by the Navy’s Office of Reconnaissance,
Electronic Warfare and Special Operations and the CIA,
Muddy Hill was established to equip a Navy P-2H
Neptune patrol aircraft with state-of-the-art electro-optical
(EO) and other sensors and evaluate them in a nighttime
combat environment in Southeast Asia.
The P-2H was reconfigured by LTV E-Systems Inc. in
Greeneville, Texas — a company with much experience in
modifying aircraft for “black” programs — and redesignated NP-2H. Five-foot-long pods were mounted on either
side of the nose, with the port pod housing a Low-Light-Level Television camera, and the starboard pod housing an
APQ-115 terrain-following radar. A 7-foot-long probe
extending forward from the top of the nose supported the
radar’s angle-of-attack sensor.
The aircraft’s radar ventral radome was modified to
house a Forward-Looking Infrared sensor able to scan
from the horizon to 20 degrees aft of the nadir. A 6-foot-
long, 30-inch-wide fairing aft of the rear exit hatch housed
two Stereo Downward-Looking Infrared (DLIR) systems.
An additional faring housed a Fairchild Instruments
70mm-format horizon-to-horizon reconnaissance camera.
Controls and displays for the sensors were installed on
the aircraft’s flight deck. Sophisticated navigation systems
and an active electronic countermeasures system also were
The NP-2H was painted in a high-gloss black scheme
used on World War II night fighters. The wing fuel
tanks were filled with polyurethane reticulated foam to
minimize the possibility of wing fires initiated by small-to medium-caliber ground fire.
Navy officers and enlisted personnel assigned to the
project were sent to factory and university classes to learn
the fundamentals of infrared detection, low-illumination
television, starlight scopes, terrain-following radar, active
electronic countermeasures and active magnetic anomaly
detection systems. In September 1966, the Muddy Hill
personnel reported to E-Systems for training and testing.
After additional tests in California, the Muddy Hill team
relocated to Patuxent River in July 1967 for predeploy-ment preparations.
In late July, the NP-2H deployed with a flight crew of
six to Udorn Thani Royal Thai Air Force Base. Functioning as Task Group 50. 8, Muddy Hill was supported
by 41 military and civilian personnel at the Air America
compound at Udorn. To improve crew survivability, the
aircraft’s pilot and co-pilot’s seats were reinforced with
seat armor salvaged from crashed Army helicopters.
The Muddy Hill crew conducted 60 road reconnaissance training and avionics test flights around the Udorn
area. Combat missions were flown at low level, day and
night, over Laos in the Barrel Roll and Tiger Hound operational areas. Target areas consisted of the Ho Chi Minh
Trail and its road segments as well as locations in the
Plaine des Jarres in central Laos.
Mission flight parameters varied between 200 and
1,500 feet absolute altitude on terrain-following radar.
Primary target-area guidance was accomplished by use of
a hand-held Starlight night-vision scope in the Plexiglas
bow observer station to locate road segments and individual targets and direct the plane commander using voice
commands via the aircraft’s inter-communication system.
Suspected targets of interest were marked with green,
chemiluminescent dye-impregnated parachute flares
dropped from the aircraft’s sonobuoy dispensing chutes.
The Stereo DLIR system obtained infrared images directly on two rolls of 70mm film. After processing, this
film was analyzed by photographic intelligence-trained
Muddy Hill personnel using a specially designed stereoscopic viewer. Tactically significant target information was
reported to the Air Force’s intelligence center at Udorn.
In December 1967, after 14 combat missions totaling
62 hours, the Muddy Hill aircraft and project personnel
returned to Patuxent River, having successfully
deployed the first airborne EO systems to be operationally evaluated in a combat environment. These systems served as the predecessors of more modern EO
systems successfully used in 1968-69 on AP-2H aircraft
with Heavy Attack Squadron 21 and later in carrier-based A-6C Intruder aircraft. ■
Adapted with permission from the article, “Project Muddy
Hill,” published in the winter 2007/2008 edition of Wings of
Gold. Retired Navy Lt. Cmdr. Zafran, a former naval flight
officer, was the bow observer for Project Muddy Hill.