In addition to degraded Heading performance, what feature of the ADIRU is lost when the ATT mode is selected?

In addition to degraded Heading performance, what feature of the ADIRU is lost when the ATT mode is selected?

• A. Position data
• B. Attitude data
• C. Magnetic heading
• D. Rate of turn

Answer: (A)

When the ADIRU is set to ATT mode, it switches to providing only Attitude and Heading reference. It continues to supply the aircraft’s orientation and a heading reference, but the position information—the latitude/longitude solution that the inertial/navigation function normally provides—is not available in this mode. So, in addition to the heading performance being degraded, the ADIRU’s position data is lost because the navigation portion of the unit is intentionally disabled in ATT mode.

When the ADIRU is set to ATT mode, it switches to providing only Attitude and Heading reference. It continues to supply the aircraft’s orientation and a heading reference, but the position information—the latitude/longitude solution that the inertial/navigation function normally provides—is not available in this mode. So, in addition to the heading performance being degraded, the ADIRU’s position data is lost because the navigation portion of the unit is intentionally disabled in ATT mode.