The LPWS dead zone is defined as what combination of angles and altitude?

• A. +85 deg above, -100 m alt(defended wall min), 50 deg behind
• B. -85 deg above, +100 m alt, 0 deg behind
• C. +50 deg above, -200 m alt, 20 deg behind
• D. +90 deg above, -50 m alt, 60 deg behind

Answer: (A)

The dead zone is where the LPWS cannot detect or warn because of its geometry and sensor limits. It occurs in a three‑dimensional region defined by elevation, altitude, and azimuth relative to the defended asset. In this case, targets that are nearly overhead (+85 degrees elevation), below the defender’s minimum defendable altitude (-100 m), and behind the system’s line of sight (50 degrees behind) fall into that inaccessible wedge. The +85-degree elevation places the target at the extreme upper limit of the sensor’s vertical sweep, the -100 m altitude places it below the lowest usable altitude tied to the defended wall, and the 50-degree behind orientation means the system has little to no field of view in that sector. Because all three conditions align, the LPWS cannot provide warning or tracking for threats in that region, defining the dead zone. Other options would place the target inside the sensor’s usable elevation, altitude, or forward sector, and thus would not constitute the dead zone.