What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Narrative: after takeoff crew got an avionic's light, notified ATC, declared an emergency and returned to Mobile, AL. After landing there was no indication of smoke, aircraft taxied to the gate with CFR following. Passengers were deplaned, firemen and a mechanic opened the avionic bay but did not see any indication of a fire. Mechanic found a faulty smoke detector in the avionic bay. Exchange avionic bay detector with the one in the lavatory, as permel. Aircraft continues on with flight.
As the FAA filed it
NARRATIVE: AFTER TAKEOFF CREW GOT AN AVIONIC'S LIGHT, NOTIFIED ATC, DECLARED AN EMERGENCY AND RETURNED TO MOBILE, AL. AFTER LANDING THERE WAS NO INDICATION OF SMOKE, AIRCRAFT TAXIED TO THE GATE WITH CFR FOLLOWING. PASSENGERS WERE DEPLANED, FIREMEN AND A MECHANIC OPENED THE AVIONIC BAY BUT DID NOT SEE ANY INDICATION OF A FIRE. MECHANIC FOUND A FAULTY SMOKE DETECTOR IN THE AVIONIC BAY. EXCHANGE AVIONIC BAY DETECTOR WITH THE ONE IN THE LAVATORY, AS PERMEL. AIRCRAFT CONTINUES ON WITH FLIGHT.