What happened
The flight was cleared for the localizer 31 approach at Corpus Christi International Airport. During the approach, the first officer was manipulating the controls, and the crew completed the In-Range and Approach checklists.
Prior to this arrival, a different aircraft had requested the ILS RWY 13 approach, prompting the tower controller to switch the ILS localizer from runway 31 to runway 13. Following the completion of that previous approach, the tower controller failed to reselect the localizer for runway 31. Although the flightcrew tuned in the localizer frequency for Runway 31, they did not verify the signal via Morse code identification.
The captain reported that the localizer was intercepted, noting that while the course deviation bar experienced full-scale deflections initially, it locked on seven miles southeast of the final approach fix. At the time, the aircraft was flying through a broken cloud layer at 2,000 feet MSL with visibility between 5 and 6 miles.
After confirming all instruments were configured for the approach, the captain observed a runway at the northern edge of the clouds. The captain noted that the number 31 was painted on the approach end of this runway. After reporting the field in sight to approach control, the crew was instructed to contact tower control and was cleared to land. The Boeing 737-300/500 subsequently landed at Cabaniss Field, a Navy auxiliary field located 5 nautical miles southeast of Corpus Christi International Airport, which sits on the final approach course for Runway 31.
At the time of the event, the first officer was conducting his first flight of initial operating experience (IOE) following differences training. The crew members were unfamiliar with the local airport environment.