Private aviation ratings are an important way for charter customers to assess the safety and reliability of private jet operators. Here's a breakdown of some of the most commonly used ratings in the industry:

The Aviation Research Group/US (ARGUS) is a private aviation safety audit and rating company. They provide three types of ratings: ARGUS Gold, Platinum and Platinum Plus. These ratings are based on safety history, pilot experience and qualifications, aircraft maintenance records, and insurance coverage.

Wyvern Ratings: Wyvern is a global aviation safety auditing firm that focuses on providing safety and risk management solutions. Wyvern has two types of ratings: Wyvern Registered and Wyvern Wingman. The Registered rating is a basic safety audit, while the Wingman rating is a more in-depth safety audit that includes an on-site inspection of aircraft, personnel, and procedures.

IS-BAO: The International Standard for Business Aircraft Operations (IS-BAO) is a safety standard for private aviation operations. The standard is based on safety management systems and is designed to ensure that private jet operators are operating in a safe and efficient manner.

ACSF: The Air Charter Safety Foundation (ACSF) is a non-profit organization that provides safety resources and education for private aviation customers. They offer an industry audit called the Industry Audit Standard, which focuses on safety management systems, operational control, and maintenance programs.

Each rating system has its own unique methodology and criteria for evaluating private jet operators. When choosing a private jet operator, it's important to research and consider multiple ratings and to also ask the operator for their safety records and experience.