An emergency on an incoming flight prompted a ground stop at New York City’s John F. Kennedy International Airport. The Federal Aviation Administration (FAA) confirmed that Frontier Airlines Flight 3546 landed safely at JFK around 12:45 p.m. after the crew reported an engine issue, according to NBC New York.

The ground stop was in effect from 12:30 p.m. to 1:45 p.m., halting all inbound flights until 1:45 p.m. while low clouds caused additional delays for incoming travelers and hour-long backlogs for departures. The FAA stated its investigation into the incident is ongoing.

Frontier Airlines Flight 3546, an Airbus A320 departing from Luis Muñoz Marín International Airport in Puerto Rico, signaled a code 7700 emergency call, indicating a mechanical issue or urgent situation. Frontier’s captain declared the emergency as a precautionary measure during the approach to JFK. The Port Authority of New York and New Jersey confirmed the plane landed safely at 12:50 p.m., with no injuries reported.

The incident follows a previous ground stop at Newark Liberty International Airport on Wednesday afternoon due to “staffing issues,” which caused a 75-minute flight halt. Flight tracking service Flightradar24 noted the emergency code was activated during the incident. Frontier Airlines is now evaluating the aircraft to determine the cause of the mechanical issue.