What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
Flight number 483, under the call sign bluestreak 483, a us airway express flight, being operated by psa airlines, landed as scheduled at the Chattanooga airport. While taxiing to the gate, the crew started the APU and then opened the APU load valve to allow the APU to power the ac packs, and they thought they smelled something burning. They could not determine where the smell was from, so they stopped just short of the gate, declared an emergency, and proceeded with an emergency egress. All 48 passengers were evacuated safely and routed into the terminal. Contract mx did troubleshooting and determined that seepage oil from the APU was able to drain into or around the hot bleed air from the APU load valve and cause the burning smell. The APU load valve was deactivated, per the psa MEL, and the aircraft was put back into service.
As the FAA filed it
FLIGHT NUMBER 483, UNDER THE CALL SIGN BLUESTREAK 483, A US AIRWAY EXPRESS FLIGHT, BEING OPERATED BY PSA AIRLINES, LANDED AS SCHEDULED AT THE CHATTANOOGA AIRPORT. WHILE TAXIING TO THE GATE, THE CREW STARTED THE APU AND THEN OPENED THE APU LOAD VALVE TO ALLOW THE APU TO POWER THE AC PACKS, AND THEY THOUGHT THEY SMELLED SOMETHING BURNING. THEY COULD NOT DETERMINE WHERE THE SMELL WAS FROM, SO THEY STOPPED JUST SHORT OF THE GATE, DECLARED AN EMERGENCY, AND PROCEEDED WITH AN EMERGENCY EGRESS. ALL 48 PASSENGERS WERE EVACUATED SAFELY AND ROUTED INTO THE TERMINAL. CONTRACT MX DID TROUBLESHOOTING AND DETERMINED THAT SEEPAGE OIL FROM THE APU WAS ABLE TO DRAIN INTO OR AROUND THE HOT BLEED AIR FROM THE APU LOAD VALVE AND CAUSE THE BURNING SMELL. THE APU LOAD VALVE WAS DEACTIVATED, PER THE PSA MEL, AND THE AIRCRAFT WAS PUT BACK INTO SERVICE.