Senate Select Committee - VIII

Pilot Distress Symbols

The Committee's investigation of pilot distress symbols as a possible source of evidence of live POWs after 1973 was the first such investigation conducted by any body of Congress.

During the war, the military services gave many pilots who flew combat missions individual authenticator numbers to identify themselves by radio or other means in the event their airplanes were shot down or crashed. During their pre-flight training, pilots were also given Escape and Evasion (E&E) signals to employ either as an evader or POW to facilitate their eventual recovery. Most pilots received training in methods of constructing these E&E symbols in survival courses, prior to assignment to Vietnam. Both E&E symbols and authenticator numbers were classified.

It was expected that these symbols would be used to attract rescuers and would be deployed in ways which would avoid ground detection and yet be visible to overhead collecting sources. Consequently, intelligence analysts have been encumbered with the difficult task of searching for signals which could be extremely faint, or a clever blend of natural and man-made features.

The Committee became interested in this area while looking into intelligence concerning the reported presence of POWs at a camp near Nhom Marrott, Laos, in 1980. This intelligence included the discovery of what appeared to be a "52", possibly followed by a "K" in the prison garden. It was learned that "K" was a pilot distress signal used during the war.

The Committee discovered that the intelligence community had other overhead photographs, taken by both airborne and satellite collection platforms, showing what appeared to be symbols or unexplained markings.

The earliest example was a four digit set of numbers followed by what appeared to be the letters "TH" found on a May, 1973 photograph of an area in central Laos. According to the Joint Service SERE Agency (JSSA), the four digit number could be an authenticator number followed by the primary and back-up distress symbols of a downed pilot. Another example was a 1975 photograph of a prison facility in Vietnam, in which the CIA noted unusual markings on the roof of one of the buildings. Although the CIA analysts assessed as remote the possibility that this represented a signal from a POW, they noted that the markings might be transposed to the letter "K" in Morse code. The Committee also learned of a 1988 photograph of a valley near Sam Neua, Laos, showing what clearly was a "USA" dug into a rice paddy. Beneath the "USA", DIA also noted a possible "K" created by "ground scarring."

During its investigation, the Committee was surprised by statements from DIA and CIA imagery analysts directly involved in POW/MIA work that they were not very knowledgeable about the military's E&E signals or, in some cases, even aware of the program. These analysts were not even tasked to look for such information prior to April, 1992. The Committee concluded that there had not been a purposeful effort to search for distress signals, or a written formal requirement for symbols, after the end of the war. The Committee is confident, however, that if a symbol appeared clearly on imagery, it would be identified by imagery analysts, as was the case with the 1988 "USA" symbol.

The Committee recommends that the search for possible POW distress symbols in Southeast Asia be a written intelligence requirement and that imagery analysts be educated fully about JSSA training. This is because a prisoner under detention is not likely to have the opportunity to construct distress signals that are blatant or elaborate; they are, in fact, trained to use discreet methods to avoid detection. The more familiar imagery analysts are with JSSA training, the more likely it is that they will be able to detect such a discreet signal. Also, given the possibility that past signals could have been missed, the Committee recommends that past photography of suspect detention sites be reviewed to the extent that resources permit.

The Committee notes that JSSA officials had not been consulted previously with respect to the suspected symbols, except for the 1973 "TH" photograph, which was shown to them in the mid-1980's. Accordingly, the Committee asked JSSA to evaluate a number of possible symbols and markings to see if they were consistent with JSSA training methods and distress symbols used during the war. JSSA concluded that the "USA, possible K", the "52 possible K", the "TH" , the roof top markings and one other symbol were consistent with the methods taught to pilots downed in Laos. JSSA analysis of the "USA possible K" concluded that this should be considered a valid distress symbol until proven otherwise. It should be emphasized, however, that JSSA officials are not trained in photo analysis, and are not qualified to determine whether, in fact, symbols that may seem to appear in imagery actually exist.

The Committee notes that imagery anomalies are caused by regularly occurring natural phenomena and that JSSA originally identified 150 such numbers during its review of photography, of which 19 appeared to match the four-digit authenticator numbers of U.S. airmen. It was later demonstrated to the satisfaction of all parties that none of these numbers were man-made, and all were naturally occurring phenomena such as shadows, ridges, or trees, with the exception of one additional symbol identified by one consultant in an altogether different location.

The DIA does not dispute that two of the possible symbols, the "USA" in 1988, and the 1973 "TH" are intentionally-constructed man- made symbols. In a message to the Committee received in January, 1993, however, the agency stated that the "'USA' symbol was not a distress symbol and had nothing to do with missing Americans." This finding was based on a December, 1992 on-site investigation which "determined that the symbol was made by Hmong tribe members." In the same message, the DIA raised the possibility that the 1973 "TH" symbol may have been made by a Hmong tribesman whose name started with the English letters "TH" and who was a passenger on an aircraft piloted by the American Emmet Kay which went down in May, 1973, "a few kilometers" away from where the symbol appeared.

DIA now contends that the "52", possible "K" seen at Nhom Marrott is the result of shadowing and in no way represents a pilot distress symbol. The Committee notes, however, that DIA had earlier discounted the possibility that the symbol was caused by shadowing because of the constant shape of the figures over a period of days and at different times of the day. In fact, the intelligence community had concluded in 1980 that this symbol had been dug into the ground intentionally.

Due to the complexity of interpreting symbols obtained through imagery, the Committee decided to hire two independent imagery consultants. Each consultant was given access to the necessary equipment and each submitted independently a report to the Committee. The consultants' reports, which differed on only the one symbol referred to earlier, were subsequently provided to the intelligence community for its comments and evaluation.

A joint task group of DIA, CIA and NPIC imagery analysts found that an unresolved symbol found by one consultant was "probably not man- made." This consultant had detected, with "100 percent confidence" a faint "GX 2527" in a photograph of a prison facility in Vietnam taken in June, 1992. This number correlates to the primary and back-up distress symbols and authenticator number of a pilot lost in Laos in 1969. The joint agency team agreed that there were visible markings that could be interpreted as letters and numbers, but concluded that the marking "appeared" too "haphazard and ill- defined" to be man-made distress symbols.

Disagreement arose within the Committee about the interpretation of some of the possible symbols, including the question of whether there is reason to believe that the "GX 2527" symbol is man-made, rather than the result of natural phenomena. However, the Committee agrees that the benefit of the doubt should go to the individual in this case, because the apparent number corresponds to a particular authenticator number and because it was identified by one analyst with 100 percent confidence. Accordingly, the Committee urges the appropriate officials in the Executive branch to request information about the serviceman involved from the Government of Vietnam.

Although the Committee cannot rule out the possibility that U.S. POWs have attempted to signal their status to aerial observers, the Committee cannot conclude, based on its own investigation and the guidance of imagery experts, that this has definitely happened. Although there is now an adequate collection process in place, the Committee investigators found unacceptable lapses in time between the point of collection and evaluation; and between evaluation and follow-up. The Committee recommends better integration among the various intelligence agencies, including improved training and a better system for collecting and acting on information gathered through imagery.