The Bermuda Airport Authority is investigating why the emergency generator was not able to maintain communication at the island’s air traffic control tower after a power outage this week.

Lester Nelson, the chief executive of the BAA, said that all four generators were maintained in accordance with best practices.

The tower at LF Wade International Airport temporarily lost communications during the power cut on Monday, forcing a Bermuda-bound American Airlines flight to return to Miami.

Two inbound BermudAir flights were able to land using contingency radio equipment.

Mr Nelson said: “BAA is investigating why the ATC emergency generator, one of four EGs, did not provide the necessary secondary power on demand.

“The system is tested twice a month and is back in operation.

“The early investigation has revealed that all four of our EGs have been maintained in accordance with best practices.

“The failure of the EG to function was rare and we are pleased that our third-tier contingency was effective.

“Our goal will be to further minimise disruption to our airline customers and the public while providing safe air navigation and weather services.”

He added: “Emergency generators are large diesel engines with many moving mechanical and electrical parts. Failure is mitigated through routine testing and planned preventive maintenance.

“While failure rates are very low, we will continue to improve our third level of contingency which includes extending the UPS [battery] duration and procedures.”

The power outage affected mostly eastern parishes at 9.55pm on Monday and electricity was restored just after 11pm.

As well as the island’s ATC and the Bermuda Weather Service, both run by the BAA, it also affected operations at the Federal Aviation Administration’s New York ATC, which controls air traffic out to 200 miles from Bermuda.

Mr Nelson added: “Bermuda tower was able to communicate with the two inbound BermudAir flights, using contingency radio equipment, in order to facilitate their safe arrival at the LF Wade International Airport.

“Meanwhile, New York Centre issued a ground stop for all flights travelling to and from Bermuda, which caused AAL409 to return to Miami.

“This was the only disruption to passenger flight operations.”