When is the LG WRN INHIB switch used?

• A. To silence the landing gear warning in all conditions
• B. To inhibit the landing gear warning in the event of a dual radio altimeter failure
• C. To silence the warning during takeoff
• D. To reset the landing gear warning after landing

Answer: (B)

The switch is used when the aircraft’s dual radio altimeters have failed or are unreliable. Normally the landing gear warning system uses altitude data from the radio altimeters to decide if a warning is needed when the gear isn’t down. If both rad alt sources fail, that altitude information becomes untrustworthy and a false or nuisance warning could occur. In that situation, the LG WRN INHIB switch is used to silence the landing gear warning, preventing an unnecessary horn or alert while you manage the RA failure and continue the approach or flight. It isn’t intended for general silencing, during takeoff, or as a routine reset after landing; it’s specifically for the dual radio altimeter failure condition, after which you restore the warning once the issue is resolved.