If cloud height equipment for the active runway is inoperative and the measurements from the inactive runway are representative, which data source may be used?

If cloud height equipment for the active runway is inoperative and the measurements from the inactive runway are representative, which data source may be used?

• A. Active runway data only
• B. Inactive runway data only if not representative
• C. No data
• D. Inactive runway data if measurements are representative

Answer: (D)

When the active runway’s cloud height equipment is inoperative, you need a substitute that still reflects the conditions affecting the active runway. Measurements from the inactive runway can be used, but only if they are representative of the active runway conditions. If those readings accurately mirror the ceiling and visibility for the active runway, they provide valid data for safe operations. If they aren’t representative, you cannot substitute them and would have no reliable data for that parameter. So the best approach is to use the inactive runway data when its measurements are representative.

When the active runway’s cloud height equipment is inoperative, you need a substitute that still reflects the conditions affecting the active runway. Measurements from the inactive runway can be used, but only if they are representative of the active runway conditions. If those readings accurately mirror the ceiling and visibility for the active runway, they provide valid data for safe operations. If they aren’t representative, you cannot substitute them and would have no reliable data for that parameter. So the best approach is to use the inactive runway data when its measurements are representative.