What does SSV stand for aviation?

Inquiring minds want to know: Could you please elucidate on the acronym "SSV" in the context of aviation? Is it a specific technology, a type of aircraft, or perhaps a regulatory standard? The aviation industry is vast and diverse, with numerous abbreviations and acronyms used on a daily basis. Understanding the meaning behind "SSV" could be crucial for professionals working in this field. Could you clarify its significance and potential applications? Thank you for your assistance in deciphering this aviation-related acronym.