Follow the steps to successfully complete the DC OST 4507 form online.

1. Click the ‘Get Form’ button to access the DC OST 4507 form and open it in your preferred document editor.
2. Begin by providing the name of the registering carrier and mailing address in section 1a. If applicable, include the 'Doing Business As' (DBA) name.
3. In section 2a, enter the address of the principal place of business, if different from the mailing address provided in step 2.
4. Fill in section 3 with the Federal Aviation Administration (FAA) certificate number, local FAA office address, and telephone information as required.
5. Indicate in section 4 whether this filing is an initial registration or an amendment, and if it's an initial registration, state the proposed date of commencement of operations.
6. In section 5, check the type of service you intend to provide, whether it is scheduled passenger, on-demand passenger, air ambulance, etc.
7. List the aircraft you intend to operate in air taxi service in section 6. For each aircraft, fill in the make, model, FAA registration number, and the number of passenger seats installed.
8. Answer section 7 regarding the registering carrier's citizenship status, ensuring to select 'YES' or 'NO' appropriately.
9. If applicable, in section 8, indicate whether the carrier has carried passengers in foreign air transportation during the past 12 months.
10. In section 9, report any changes or amendments to previous filings within 30 days, including name and address changes or changes to the aircraft.
11. Complete the certification in section 10 by signing and dating the form. Provide your title and typed name to ensure your application is processed correctly.
12. Finally, review the entire form for completeness, save your changes, and proceed to submit the form along with any required documentation to the specified address.

Start completing the DC OST 4507 form online to ensure your air taxi operations are properly authorized.