FAA Aircraft Dispatcher (ADX)Navigation and ATCEasy
A dispatcher is briefing a captain on approach minimums for a CAT II ILS approach. What decision height (DH) and runway visual range (RVR) apply to this category?
- ANo DH and RVR not less than 300 feet
- BDH not lower than 200 feet and RVR not less than 2400 feet
- CDH not lower than 100 feet and RVR not less than 1200 feet
- DDH not lower than 50 feet and RVR not less than 700 feet
Show answer & explanationAnswer & explanation
Correct answer: C. DH not lower than 100 feet and RVR not less than 1200 feet
CAT II ILS approaches allow a decision height as low as 100 feet with an RVR of 1200 feet, requiring additional aircraft equipment, crew training, and airport facilities beyond CAT I standards.
Why the other options are wrong
- A. CAT IIIB uses RVR 150 ft with no DH; 300 ft RVR with no DH is not a standard category.
- B. These are typical CAT I minimums, not CAT II.
- D. These figures correspond to CAT IIIA, which has no or a very low DH.
ILS Approach Categories
ILS approaches are categorized by decreasing decision height and visibility requirements as ground and airborne equipment capability increases.
- CAT I: DH 200 ft, RVR 1800/2400 ft
- CAT II: DH 100 ft, RVR 1200 ft
- CAT IIIA: DH <100 ft or no DH, RVR 700 ft
- CAT IIIB: DH <50 ft or no DH, RVR 150 ft
- CAT IIIC: no DH, no RVR restriction
Memory trick: 'I See Less' as category number increases — lower minimums each step.