Definition
A requirement, in airspace where Reduced Vertical Separation Minimum (RVSM) applies, that an aircraft's Traffic Alert and Collision Avoidance System (if installed) be a version capable of operating correctly with only 1,000 feet of vertical separation between aircraft above FL290. In practice this means TCAS II Version 7.0 or later, which has logic suited to RVSM separation; earlier versions can generate nuisance alerts and are not approved for RVSM operations.
Plain English
If your aircraft has a collision-avoidance system and you want to fly in RVSM airspace, that system has to be a modern version that knows aircraft will be flying just 1,000 feet apart up high, instead of the older 2,000 feet. Older versions get confused by the closer spacing and aren't allowed.
Context Anchor
Seen in RVSM equipment and approval discussions, especially when checking whether an aircraft may operate in RVSM airspace.
Derivation
TCAS stands for Traffic Alert and Collision Avoidance System. 'Compatibility' here means 'works correctly with' -- specifically, works correctly with the tighter 1,000-foot vertical spacing used in RVSM airspace.
Why Pilots Care
Ensures crews are not distracted by false alerts or forced into unnecessary climbs or descents while operating in closely spaced RVSM traffic.
Intuition Check
Do not read compatibility as simply “the airplane has TCAS.” In this context, it means the installed TCAS setup is suitable for RVSM operations.
Example Sentence 1
Before dispatching the aircraft into RVSM airspace, the operator confirmed TCAS compatibility by verifying the unit was running Version 7.0 software.
Example Sentence 2
During preflight, the crew verified that the installed TCAS met compatibility standards for the planned RVSM route.