As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HYDRAULIC SIGHT GLASS IS A 4 INCH PIECE OF TUBE LOCATED ON THE FIREWALL IN THE NOSE CARGO BAY. IT IS PROTECTED BY A PIECE OF PLEXIGLASS. PLEXIGLASS WAS NOT DAMAGED, THE 4 INCH TUBE BECAME BRITTLE OVER THE YEARS. NOW WILL INCLUDE A REPLACEMENT OF THE HOSE WITH THE AC 1000 HOUR INSPECTION. THE LEAKING HYDRAULIC FLUID WENT DOWN THRU THE NOSE GEAR TUNNEL, CONTACTING THE HEATER CAUSING SMOKE IN THE COCKPIT. (K)