Modification 262: 5.5 PSI differential pressure Modification 264: 30,000 ft service ceiling. According to Aerostar AMM, chapter 4, Airworthiness limitations: Limitation for Option 262 and 264, widshield and windows must be replaced at 9900 hours. Aircraft approved for operation at 30,000 ft ceiling Inconal exhausts and tail pipe (allows higher TIT) Inconel front EXHAUST SYSTEM SERVICE BULETIN 600-123 carried out 12/03/97 Six puck heavy duty brakes, (3 brake calipers on each wheel, important for operation on short runways) Dual Three piston caliper brake conversion kit installed. FIKI certified per Flight Manual Supplement 17, Ice protection system, Approved for flight into known icing condition. Machen pneumatic door seal pressure system 65-30 S.N.65-30-020. Oil Breather Recovery System, Machen 62-1.2 option two, optional oil breather separator Oil Scavenge Pumps Air conditioning De-Ice system Oxygen Cylinder Machen Aux Tank Vortex Generators Aircraft Cover