73rd
Surveillance Airplane Company (SAC) - Home PageThe OV-1A, B or C model Mohawk with its various sensor systems is the best equipped and most sophisticated reconnaissance aircraft in the Army's inventory. However, it does have its limitations which can be misinterpreted or not understood by those commanders it supports.
Credits
"SNEAKY PETE
99, this is Delta Hawk 3. I have a mover at coordinates XT 123456, over.""Delta Hawk 3, this is Sneaky Pete 99. Would you describe the target, its direction of movement, speed, number and whether it's friendly or Charlie? Over."
"Sneaky Pete 99, I don't have that capability, over."
"O.K. Delta Hawk 3, this is Pete. Earlier tonight I saw a squad of VC walking past my position. Why didn't you warn me? Over."
"Sorry about that Pete. Next time you come down to your home base drop over and see us and we'll let you know how we can help you and show you why we couldn't see that squad of troops."
"All right, Delta Hawk, I'll be down to see you Monday, Put the coffee pot on."
"Will do, Sneaky Pete. Delta Hawk 3 departing your area for now- -be back in about 45 minutes. Out."
This is a true radio conversation; only the call signs have been changed to protect the innocent, or guilty. The conversation was between an OV-1B Mohawk on a side looking airborne radar (SLAR) mission at night and a Special Forces outpost not too far from a well-known border area.
Do you know why the SLAR ship was there, the significance of the "mover" he spotted and why he couldn't answer all the questions that were asked? OV-l Mohawks have been operating in the Republic of Vietnam for quite some time, from the tip of Ca Mau to the DMZ both day and night and in the middle of some "raunchy" weather. Yet many personnel, including Army aviators, don't know just what these OV-ls can and are doing for the war effort.
The general lack of knowledge of the OV-l units and sensor systems can be traced to the classified nature of both during their initial introduction in Vietnam. However, much nontechnical information concerning these operations has been declassified and can be discussed.
Let's start with a thumbnail sketch of the history of surveillance. Prior to the Civil War surveillance was confined to eyeball observation by the front-line soldier. This type surveillance had certain limitations caused by weather, darkness, visibility and the human factor of reliability. During the Civil War surveillance was accomplished by an observer sent aloft in a balloon. This placed the observer in a very precarious position but it extended the surveillance range and improved visibility slightly. Nevertheless, there still were critical limitations due to weather, darkness, visibility and reliability.
The introduction of the airplane in World War I provided a greater capability to observe the enemy. For the first time a commander could select and change the surveillance area, and mobility was no longer considered a limiting factor. Further improvements were made in World War II with the introduction of the aerial camera. This equipment helped to overcome the limitations of human reliability to a degree and provided the commander with a fixed imagery to study. The only limiting factors remaining were weather and darkness. There were no further major advances in the surveillance field through the Korean War. In the late 1950s radar equipment was developed that could detect infrared rays.
Since 1960 virtually all of the earlier limiting factors have been eliminated and the capability exists to conduct sustained, near all weather, day and night, visual photographic and electronic surveillance of the battle area. Additionally, capabilities are increasing so rapidly that a thorough initial understanding, as well as a periodic updating of the art, is necessary. This is where the problem begins. Even aviators with an understanding of the surveillance capability are not normally flying OV-ls or in a position to be updated on new developments. Still, nonrated personnel consider any Army aviator from W-l to general officer as an expert in all aspects of the Army flying business. But, how many are qualified to advise a ground commander on the most efficient way to use the surveillance aircraft and sensors available to support him? Few are. The answer is to educate personnel who are in a position to influence the mission assigned the surveillance airplane company.
Let's look at the company mission, some organization information and a layman's explanation of the sensor systems.
The surveillance airplane company is organized to provide combat surveillance and reconnaissance capabilities normally to a corps or division, if requested, through the use of OV-l Mohawks equipped with infrared, side looking airborne radar, day and night camera systems and ground data stations. In short, the unit has the necessary experts and equipment to collect, interpret and disseminate information gained from aerial imagery. The unit normally is under the operational control of the corps G-2 air even though assigned to an aviation battalion. Mission requests are funneled through the intelligence channels to the corps G-2 air. This sounds like a lot of distance to travel with many headquarters to go through, but the unit prides itself in being immediately responsive to the ground commanders' desires. A misunderstanding of the sensor capabilities could cause unnecessary delays in mission accomplishment.
The unit is tailored to provide sustained, near all-weather, day or night surveillance of the entire corps area by using visual, photographic, side looking airborne radar and infrared systems. The imagery produced by the systems is processed and interpreted with the information disseminated to units by radio, telephone and teletype.
Sounds great, but let's be realistic and mention a few of the unit's limitations. No matter what anyone says the OV-l used in its intended role in Vietnam is not a short field aircraft. When mission-ready it must be operated from improved airfields because of high gross weights and the sensitivity of the sensor systems to the abuse of dirt or makeshift runways. Ideally, the unit operates from a fully instrumented airfield to take advantage of its IFR capabilities. The unit also is dependent upon higher headquarters to provide administrative and logistical support.
Command and control aircraft are not provided by the TOE, nor is an OV-l with dual controls for standardization and orientation of new aviators. Most units in Vietnam have acquired a dual control ship by removing the infrared sensor from an OV-IC and installing dual controls or by assignment of a dual control aircraft above TOE authorization. Commanders also should realize that a surveillance airplane company contains by TOE 18 OV-ls and over 140 pieces of rolling stock varying from a one-quarter ton trailer to a semi van. This is not a small out-fit--a fact that becomes quite apparent when trying to find a place to park on a tactical airfield.
The company is organized with a company headquarters, operations platoon, surveillance platoon, signal platoon and a services platoon. For the most part this organization looks familiar with the exception of the surveillance platoon.
The company headquarters has the normal command and control element but differs in the mess and vehicle maintenance areas. The mess hall must provide meals on a 24-hour basis because the unit normally flies operational missions throughout, while maintenance generally is performed during daylight hours. The motor pool provides maintenance for a multiple of power generators as well as vehicles and trailers. The mess and motor maintenance requirements rival that of a normal battalion.
The operations platoon is the hub of activity for the company as in any aviation unit. However, major differences exist in the surveillance airplane company operations platoon. In addition to normal flight operations scheduling, this platoon has an imagery interpretation section assigned to extract and disseminate information from the imagery produced by the aircraft sensors. This task requires highly trained intelligence specialists to extract information from photographic infrared and SLAR imagery. The section has the necessary military intelligence corps officers and enlisted men assigned to man two tactical imagery interpretation facilities in 12-hour shifts. Imagery is reported in either mission reports (30 minutes), hot imagery reports (1 hour), immediate imagery interpretation reports (4 hours) or detailed interpretation reports when requested by the supported unit. The importance of this section lies in the fact that the imagery interpretation experts will provide the supported unit with information rather than imagery that must be analyzed by untrained personnel.
The signal platoon is a large organization in that it must provide personnel and equipment to:
The surveillance platoon is responsible for the conduct of the mission and has the necessary aircraft, aviators, crew chiefs and sensor operators to accomplish the collection of information and imagery. To understand how the platoon performs its mission requires a knowledge of the equipment with which it works.
Let's begin with the aircraft. The OV-l is a highly sophisticated aircraft powered by two Lycoming 1,100 shaft horsepower (SHP) engines driving Hamilton Standard fully reversible props. Normal cruise air speed is about 220 mph. The Mohawk also has two Martin-Baker ejection seats capable of getting the pilot and observer from the aircraft to suspension in a fully inflated parachute in 7 seconds with an initial force of 19 g's. The normal station time of the aircraft with external fuel tanks is about 3 hours and the cockpit instrumentation is such that IFR flying becomes a pleasure. (The auto pilot sure helps here.) The aircraft has been manufactured in three different models with a fourth expected off the production line in the near future.
The OV-1A was first off the production line in 1960. It had 950 SHP engines, dual controls and a built-in KS-61 camera system (a KA-60 panoramic camera was added later). It was used primarily for transition training, visual and photographic reconnaissance and surveillance missions.
The KS-61 camera system employs the KA-30 camera that can be positioned in flight to provide vertical (with 20 to 80 percent forward overlap) or 15 and 30 degree oblique photos. The system can be used at night with a strobe unit (240 prints) or photo flash cartridges (101 prints). A word of warning: the photo flash cartridges sound exactly like incoming mortar rounds when fired within about 1 mile of your position. This camera system has a limited area coverage; therefore, it is best utilized for spot photography, strip mosaics or small area mosaics. The KA-60 panoramic camera installed on the OV-1A and OV-1C is fixed-mounted in the nose of the aircraft and provides a horizon-to-horizon photographic capability specifically designed for high-speed, low-flying aircraft. This camera is especially valuable for taking photographs of helicopter landing zones from the planned helicopter flight approach path.
The OV-IB is equipped with the AN/APS-94 side looking airborne radar (SLAR) system. It is easily identified by the black radar antenna slung beneath the fuselage and extending beyond the nose of the aircraft. The SLAR system simultaneously produces both fixed (permanent echo (PE)) and moving target indications (MTI) presentations on film in the cockpit of the aircraft. The SLAR is an active system that transmits a radar beam which is reflected back to the aircraft and is capable of detecting slowly moving objects within certain surface reflection limitations (personnel usually do not provide an adequately reflective surface). The PE mode of operation produces a radar map of the terrain and displays fixed target information (ETI) and the MTI mode records moving target information.
The range of the SLAR system makes it ideal to use in the continuous surveillance of large areas such as coasts or borders.
The sensor operator can select from a variety of ranges on either the right or left side of the flight path or both simultaneously.
The heart of the SLAR system is a rapid data processor located in the cockpit. It rapidly processes film exposed by the radar and the processed imagery passes across a lighted viewing screen allowing the sensor operator to transpose the viewed targets to a tactical map. A well-trained and experienced operator can plot a moving target and rapidly transmit an inflight spot report after viewing the imagery.
This rapid transmission of target data combined with the fact that the system operates in day or night and in poor weather conditions makes it an extremely valuable information collection device. The effectiveness of the system is limited in extreme weather conditions (heavy rain, sleet, etc.) and is vulnerable to electronic counter-measures. However, there are few encounters with either of these two limiting factors.
The SLAR system also can transmit signals from the system to a ground station that has equipment almost identical to that in the aircraft.
The system does have significant limitations such as:
The amount of energy in the form of radiated heat is determined by the ability of the object to radiate and its temperature. The infrared system detects even minute differences in the emitted radiation of objects close to each other, thereby differentiating between them. Enough on infrared theory. The ir system employed in the Mohawk scans the terrain directly beneath the aircraft and senses the radiated temperature variations between the terrain and objects on the terrain. This variation is changed to an electrical impulse that exposes photographic film to make a permanent imagery record.
The ir aircraft are equipped for a real time pictorial display of the ir returns as the aircraft is passing over the terrain. The ability to detect a target and plot its exact location while in flight with the present system is almost impossible. Later models of ir systems may improve this capability somewhat. The ir system will operate in day or night but is most effectively employed at night as the natural cooling of the ground permits a larger heat emission differential between objects and the terrain.
The infrared system is not an area surveillance device because it scans directly beneath the flight of the aircraft and has operational altitude limitations. Therefore, the system is generally employed to provide coverage of routes, small areas and suspected enemy locations or installations. All information received by the airborne infrared sensors can be simultaneously transmitted to a ground sensor terminal that contains identical display and recording equipment to that in the aircraft. The range is limited by line-of-sight transmission.
The ir system is not operable in all types of weather since it can not receive heat emissions through cloud layers, dense jungle or other similar heat-absorbing environments. Operations in mountainous areas is less effective than in flat terrain because of the necessity to fly at higher altitudes at night.
There are definite limitations to the ir system but some of these will be overcome with newer versions. The primary limitations are:
The OV-ls with their installed equipment have provided invaluable intelligence information for analysis by the experts in Vietnam. As combat experience is gained and with the addition of newer and more advanced systems, the units' capabilities will continue to improve.
You can do your part as an Army aviator by staying abreast of the latest innovations in this field and by helping to see that these systems are properly utilized by the ground unit commanders.
73rd
Surveillance Airplane Company (SAC) - Home PageNo restricted and/or classified information is contained herein. This home page and web site have been constructed and will be maintained entirely by the author, and the author is responsible for the contents and accuracy of this site. The contents of this page have not been reviewed, approved, or monitored by the United States Army, nor is this page and/or it's contents a representation of such. All comments, questions, and concerns should be directed to the author - John E. Akers
The proceeding story has been retracted, in its entirety, from the U. S. Army Aviation Digest, September, 1970 (Vol. 16, No. 9). Reprinted with permission. Permission statement is located inside the jacket cover of the digest.
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