Southwest Airlines Co. is making an unusual test flight as it seeks regulatory approval to start service to Hawaii: a one-time nonstop from Honolulu to Dallas on a Boeing Co. 737-800.

At almost 3,400 nautical miles, the route is about 300 miles beyond the jetliner’s normal range when stuffed with passengers. But “favorable tailwinds and a light aircraft load” will make it work, Dallas-based Southwest said by email. The carrier had initially planned a landing on the West Coast.

Flight 8725 on Wednesday—with no paying passengers—will be the second part of Southwest’s first-ever trip to Hawaii as the airline seeks to begin regular service to the islands. The plane flew from Oakland, California, to Honolulu on Tuesday, enabling U.S. inspectors to evaluate Southwest’s communication and navigation procedures during long flights over water.

The scheduled flight time is six hours and 39 minutes, with an expected arrival at 7:49 p.m. at Dallas Love Field. Don’t look for a repeat—the flight “does not indicate any service intentions beyond those we’ve already announced,” said Southwest, which is planning to serve Hawaii from four California cities.