NEW YORK, Oct 11 (Reuters) - Southwest Airlines Co and United Aviation Fuels Corp have complained to U.S. regulators about the fees charged by Colonial Pipeline Co to ship refined products on the country's largest fuel network, the latest of several similar complaints against the operator.
* Colonial's rates to ship refined products, such as motor gasoline, diesel and jet fuel, on Colonial Pipeline are "unjust and unreasonable," said Southwest and UAFC in their complaint to the Federal Energy Regulatory Commission on Tuesday
* The pipeline's interstate revenue in 2017 exceeded its interstate cost of service by an estimated $321.2 million, evidence of its "excess earnings," the complaint said
* Colonial could not immediately be reached for comment
* Other companies, such as Chevron Products Co, Valero Marketing & Supply Co and Epsilon Trading LLC, the trading arm of Delta Air Lines Inc, have previously complained to FERC about Colonial's fee structure
* FERC in September appointed a settlement judge to oversee negotiations between these companies and Colonial
* Colonial Pipeline connects Gulf Coast refineries with markets across the southern and eastern United States through more than 5,500 miles (8,851 km) of its pipeline system (Reporting by Stephanie Kelly; Editing by Bernadette Baum)