Original Date: 05/01/2000
Revision Date: 01/18/2007

Northrop Grumman Defensive Systems Division (DSD) is a leader in Built-In-Test (BIT) design and implementation. Traditional BITs are relatively effective for systems built in the last 15 years, but they tend to be primitive, inadequate, and unreliable. As military flight hardware becomes more sophisticated, BITs must be able to provide mission-oriented information (e.g., system readiness, functional failure, failure criticality, capability remaining), as well as maintenance-oriented information (system operational status, fault detection and isolation, storage of test data, verification of repairs). In response, Northrop Grumman DSD has developed a new process for BITs.

The company also wanted its revised BIT process to use less test equipment, reduce test and repair times, and minimize operator skill level. Several of Northrop Grumman DSD’s aircraft electronic warfare systems now require no-flight line test equipment. The company’s revised BIT process includes a Diagnostic Knowledge Base (DKB) which is implemented on a PCMCIA card. The DKB can quickly and completely isolate failures in complex military systems to one-line replaceable unit by using the functional element testing concept. BIT information can also be revised and updated through the DKB.

Northrop Grumman’s BIT process is quick, reliable, simple, and cost effective. Benefits include rapid testing (30 seconds to two minutes); significant reduction of false alarms and pulls; operational by a low-skill, one-person interface; automatic fault detection and isolation; and less support equipment and training requirements. The BIT log data can also provide additional information, enabling the user to understand the condition. The DKB can be downloaded or updated independently of the aircraft’s Operational Flight Program.

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