The city’s 911 Computer Aided Dispatch system was down for about an hour on Monday, forcing dispatchers to manually write down the emergency calls, said an FDNY spokeswoman.

The system was up and running again by the late afternoon, she said.

The troubled dispatch system was blamed for the delayed response that resulted in two half siblings dying in a fire in Far Rockaway in April. More than 20 minutes elapsed before emergency responders made it to the burning home.