Electricians will conduct more diagnostic test tomorrow in a bid to determine what tripped a circuit breaker that protects the main runway lights at Mackay Airport.

The runway lights blacked out just after 7 p.m. on Saturday.

A Jetstar passenger jet was kept on a holding pattern for about 15 minutes while airport security staff and emergency services positioned portable battery-powered lighting along the runway.

The aircraft made an incident-free landing at 7.30 p.m.

Mackay Airport operations manager Ray Waters said technicians conducted a detailed examination of the circuitry on Saturday night and again today.

“All we can really say at this stage is that the circuit breaker tripped and blackout out the runway lights,” he said.

“It’s unclear if the fault was linked to a power spike or surge. The breaker was reset and tested on the night and on Sunday. Everything is working normally.

 “This to my knowledge has never happened before.”

Mr Waters said the Mackay Port Authority and Airservices Australia have been undertaking a major upgrade of the interface between the airport lighting and the tower control over the past two years.

A cross over to a new digital system is expected to be completed on Wednesday.

Mr Waters said Jetstar Flight 846 touched down nine minutes late on Saturday night. The service left Mackay using normal runway lighting at 8.08 p.m. – 13 minutes behind schedule.