FAA Instrument Rating Airplane (IRA)IFR Procedures and ChartsEasy
A pilot is flying an ILS approach to Runway 36. The approach chart indicates an ILS critical area protection is required when the ceiling is less than 800 feet and/or visibility is less than 2 miles. The current ATIS reports an 800-foot overcast ceiling and 1 1/2 miles visibility. Which of the following is true regarding ILS critical area protection?
- AILS critical area protection is required only if both the ceiling and visibility are below the stated values.
- BILS critical area protection is not required since the visibility is above the minimums for the approach.
- CILS critical area protection is required due to the reported visibility.
- DILS critical area protection is not required since the ceiling is exactly 800 feet.
Show answer & explanationAnswer & explanation
Correct answer: C. ILS critical area protection is required due to the reported visibility.
ILS critical area protection is required when either the ceiling or visibility (or both) are below the stated values. In this scenario, the visibility is 1 1/2 miles, which is less than the 2 miles threshold, thus requiring protection.
Why the other options are wrong
- A. The wording 'and/or' means that if either condition is met, critical area protection is required, not necessarily both.
- B. The 2-mile visibility threshold refers to the requirement for critical area protection, not the approach minimums themselves.
- D. The condition states 'less than 800 feet AND/OR less than 2 miles'. The 'or' means if either condition is met, protection is required.
ILS Critical Area Protection
Areas around the localizer and glideslope antennas that must be kept clear of aircraft and vehicles to prevent signal interference when weather conditions are at or below specified minimums.
- Protects localizer and glideslope signals.
- Required when ceiling is below specified value AND/OR visibility is below specified value.
- Specific values are published on approach charts or in airport/facilities directories.
Memory trick: Critical Area: 'OR' means 'protect the core'.