What message should you notify ATC when RVSM fails?

• A. NEGATIVE RVSM + intended course of action
• B. RVSM unavailable, request altitude change
• C. Request immediate radar vectors
• D. PAN or MAYDAY

Answer: (A)

When RVSM capability is not available, you must immediately tell ATC using a standard phrase that both notes the loss and your planned action. Saying “NEGATIVE RVSM” communicates that you cannot meet the reduced vertical separation, and adding your intended course of action tells ATC how you plan to maintain safe separation (for example, maintain your present altitude or descend/ascend to a non-RVSM altitude). This combination gives ATC the exact situation and your planned maneuver, so they can reallocate altitudes or vectors as needed.

The other options don’t fit because they either don’t use the established phraseology, don’t include your intended action, or refer to an emergency that isn’t necessarily present (PAN/MAYDAY is reserved for grave and imminent danger).