Pratt & Whitney AeroPower, part of Connecticut’s United Technologies Corp., told its 535 San Diego employees last week that it’s considering integrating the operations into other Pratt & Whitney units, and may close the Kearny Mesa plant.

“This is only a proposal and no decision has been made yet,” said UTC spokesman Ray Hernandez. “If the proposal is implemented, this would not be an immediate action. It would take place in phases during an estimated two-year period.”

The company hasn’t set any timetable on when it would make a decision, and will be engaging in discussions with key stakeholders including regulatory agencies and union representatives, Hernandez said.

The San Diego plant makes auxiliary power units for aircraft that provide electrical power for jets while on the ground and back-up power for in-flight operations.

The plant was previously under Hamilton Sunstrand, a sister division of Pratt & Whitney, and also owned by UTC. When UTC acquired Goodrich in 2012, it merged Hamilton Sunstrand into Goodrich to form UTC Aerospace.

The APU operations have been going on at the site since 1980.