What happened
The FAA’s narrative, in sentence case. The FAA writes it in capitals and removes private details.
During a flight from philadelphia international airport (kphl) to Kansas City Downtown airport (kmkc), a "low hydraulic fluid" cas message was received at FL132. The crew followed the appropriate checklist and chose to continue to kmkc, planning to inspect the hydraulic fluid upon arrival. As the aircraft descended and the outside air temperature increased, the cas message cleared, and the landing gear extended without issue. Upon landing, the second-in-command (SIC) inspected the hydraulic fluid levels and found them satisfactory, coordinating with maintenance to confirm normal levels via the dipstick. Crew continuted with their planned flight schedule and departed kmkc. During the departure climb from kmkc, at 3,000 feet MSL, the aircraft experienced vibrations at 180 KIAS. The SIC observed that the left engine accessory gearbox cover was dislodged and resting on the engine cowling. An emergency was declared, and the aircraft was slowed to 130 KIAS, requesting return back to kmkc. A post-flight inspection revealed that the left engine's upper access cowling had not been properly secured after the previous inspection for oil leaks.
As the FAA filed it
DURING A FLIGHT FROM PHILADELPHIA INTERNATIONAL AIRPORT (KPHL) TO KANSAS CITY DOWNTOWN AIRPORT (KMKC), A "LOW HYDRAULIC FLUID" CAS MESSAGE WAS RECEIVED AT FL132. THE CREW FOLLOWED THE APPROPRIATE CHECKLIST AND CHOSE TO CONTINUE TO KMKC, PLANNING TO INSPECT THE HYDRAULIC FLUID UPON ARRIVAL. AS THE AIRCRAFT DESCENDED AND THE OUTSIDE AIR TEMPERATURE INCREASED, THE CAS MESSAGE CLEARED, AND THE LANDING GEAR EXTENDED WITHOUT ISSUE. UPON LANDING, THE SECOND-IN-COMMAND (SIC) INSPECTED THE HYDRAULIC FLUID LEVELS AND FOUND THEM SATISFACTORY, COORDINATING WITH MAINTENANCE TO CONFIRM NORMAL LEVELS VIA THE DIPSTICK. CREW CONTINUTED WITH THEIR PLANNED FLIGHT SCHEDULE AND DEPARTED KMKC. DURING THE DEPARTURE CLIMB FROM KMKC, AT 3,000 FEET MSL, THE AIRCRAFT EXPERIENCED VIBRATIONS AT 180 KIAS. THE SIC OBSERVED THAT THE LEFT ENGINE ACCESSORY GEARBOX COVER WAS DISLODGED AND RESTING ON THE ENGINE COWLING. AN EMERGENCY WAS DECLARED, AND THE AIRCRAFT WAS SLOWED TO 130 KIAS, REQUESTING RETURN BACK TO KMKC. A POST-FLIGHT INSPECTION REVEALED THAT THE LEFT ENGINE'S UPPER ACCESS COWLING HAD NOT BEEN PROPERLY SECURED AFTER THE PREVIOUS INSPECTION FOR OIL LEAKS.