Definition
In risk management decision-making, a backup option (such as a different course of action, route, airport, or plan) that the pilot has identified in advance as acceptable and workable should the original plan become unsafe or impractical.
Plain English
A solid Plan B that you've thought through ahead of time and know will actually work if Plan A falls apart.
Context Anchor
Used in aeronautical decision-making, especially when a pilot is comparing choices during changing conditions.
Derivation
Alternate' comes from the Latin alternatus, meaning 'one after the other' — the idea of having a second option ready to take the place of the first. 'Suitable' means 'fit for the purpose.' Together: a second option that genuinely fits the situation, not just any backup.
Why Pilots Care
Ensures a viable backup exists before departure, supporting sound go/no-go decisions and reducing the chance of an emergency diversion with no prepared option.
Grounding Statement
A suitable alternate is the option you can turn to calmly when the first option no longer makes sense.
Intuition Check
Suitable does not mean perfect, easiest, or most convenient. It means safe, legal, and practical for the situation you are actually in.
Example Sentence 1
Before departing into marginal weather, the pilot identified a suitable alternate airport with VFR conditions and adequate fuel reserves to reach it.
Example Sentence 2
When weather at the destination dropped below limits, the pilot diverted to the pre-planned suitable alternate.