The Air Force has also sent AN/PSS-12s to Bosnia. According to intelligence reports, over half of the landmines in Bosnia are buried, and about 75 percent of them are low-metallic mines. AN/PSS-12 Detector Performed Poorly Against Low-Metallic Mines in Operational Testing

The Army’s Test and Experimentation Command, under the auspices of the Operational Test and Evaluation Command, conducted two operational tests during 1991 to assess the performance of the candidate metal detectors in a field environment. The Test and Evaluation Command did state that the procurement decision should not depend too heavily on the detectors’ inability to detect low-metallic mines because such mines were just a step away from nonmetal mines, which would render a metallic mine detector useless. These results showed that against the high-metallic mine targets remaining in the operational test, all three detectors found virtually all the mines and passed the Army’s 92-percent detection requirement. Demonstrations of portable mine detectors have been conducted in a field environment; however, the detectors have been operated by contractor personnel or Army civilian personnel. Again, as in operational testing, they must contend with a variety of factors that can affect detector performance. However, this information is not consistent with the Army’s 1991 test results and information from other sources. Consequently, we believe the potential effectiveness of the AN/PSS-12 against low-metallic mines in Bosnia is inconclusive. The steps the Army has taken to minimize the threats posed by landmines there and the resultant infrequent reliance on the AN/PSS-12 may help to explain why the detector’s poor performance against low-metallic targets in testing has not been exhibited in Bosnia. We believe it is the prudent steps taken by the Army to avoid and minimize the landmine threat in Bosnia—more so than the capability of the AN/PSS-12 or the detectability of the low-metallic content mines there relative to the test targets—that explains the difference between the detector’s performance in operational testing with its experience in Bosnia.
Why GAO Did This Study

Pursuant to a congressional request, GAO reviewed the Army's development of a portable land mine detector, focusing on: (1) how the Army's AN/PSS-12 mine detector performed in detecting low-metallic mines in procurement tests; (2) the nature of the land mine threat in Bosnia-Herzegovina; and (3) the mine detector's potential effectiveness in Bosnia.

What GAO Found

GAO found that: (1) the Army has not clearly demonstrated the ability of its AN/PSS-12 mine detector to detect low metallic mines; (2) the detector performed poorly during operational testing and failed to meet the Army's 92-percent detection requirement against low metallic mines; (3) although both candidate detectors performed equally well after the Army removed low metallic targets from the procurement tests, the Army selected the AN/PSS-12 because of its lower price; (4) the detector's field accuracy is questionable, since the Army did not sufficiently control other environmental and operating factors that can affect detector performance; (5) the detector's usefulness in Bosnia may be limited because about 75 percent of the buried mines have a low metallic content; (6) although the detector's reported performance in Bosnia is good, the Army has limited the detector's use there; (7) the Air Force has warned its personnel in Bosnia that the detector is not sufficiently sensitive to low metallic mines and some countries have switched to other mine detectors; and (8) the Army has reduced its reliance on the detector through alternative threat-reduction practices, such as extensive personnel training in mine awareness, avoiding or carefully selecting routes through suspected mine fields, and using heavy equipment to clear paths.