In the context of aviation and aerospace, an "Air Carrier District Office" refers to a regional office of the Federal Aviation Administration (FAA) that is responsible for overseeing and regulating the operations of air carriers (such as airlines) within a specific geographic area.

The FAA is divided into several regions, each with its own Air Carrier District Office. These offices are responsible for ensuring that air carriers comply with federal aviation regulations, including those related to safety, security, and operations.

The Air Carrier District Office is responsible for a range of activities, including:

1. Certifying and overseeing air carriers: The office is responsible for issuing certificates to air carriers, which permit them to operate in the United States. The office also conducts regular inspections and audits to ensure that air carriers are complying with federal regulations.
2. Enforcing regulations: The office is responsible for enforcing federal aviation regulations, including those related to safety, security, and operations. This includes investigating incidents and accidents, and taking enforcement action when necessary.
3. Providing guidance and support: The office provides guidance and support to air carriers on regulatory matters, and helps them to understand and comply with federal regulations.
4. Conducting safety inspections: The office conducts regular safety inspections of air carriers, including their aircraft, facilities, and operations.
5. Investigating incidents and accidents: The office investigates incidents and accidents involving air carriers, and takes enforcement action when necessary.

The Air Carrier District Office works closely with other FAA offices, as well as with air carriers, airports, and other aviation stakeholders, to ensure the safe and efficient operation of the national airspace system.