https://avherald.com/h?article=52325375&opt=0(couldn't find the original decent, he was right between NY Center and Cleveland Center somewhere, but here's KPIT Approach to Landing)
A Republic Airways Embraer ERJ-175 on behalf of American Airlines, registration N424YX performing flight AA-4565 from New York La Guardia,NY to Indianapolis,IN (USA), was enroute at FL320 about 110nm east of Pittsburgh,PA (USA) when the crew reported an unusual odour on board and initiated a rapid descent to 10,000 feet. The crew requested medical assistance for their flight attendant be available at the runway. Later ATC advised an ambulance was at the gate, the crew requested the ambulance again at the runway to check their flight attendant. The aircraft landed safely on Pittsburgh's runway 28L, vacated the runway and stopped clear of the runway. The crew told attending emergency services, they did have smell on board, performed a rapid descent, the smell went away below 10,000 feet and requested emergency services to check for any smoke visible from the aircraft, emergency services advised they could not see any smoke.
A replacement ERJ-175 registration N425YX reached Indianapolis with a delay of about 2:15 hours.
The FAA reported: "Republic Airlines Flight 4565 landed safely around 10:55 a.m. local time on Monday, January 20 after diverting to Pittsburgh International Airport after the flight crew reported a mechanical issue. The Embraer E175 departed New York - LaGuardia and was headed to Indianapolis, IN. The FAA will investigate."
The occurrence aircraft remained on the ground for about 5.5 hours, then returned to service.
https://flightaware.com/live/flight/AAL4565/history/20250120/1425Z/KLGA/KIND
