What was found
SFO - AT 7,000 FEET, F/O'S ALTIMETER INDICATES 440 FEET LOWER THAN CAPTAIN'S ALTIMETER AND F/O'S AIRSPEED INDICATOR SHOWS 12 KIAS LESS THAN CAPTAIN'S INDICATOR. AIRCRAFT RETURNED TO STATION WITHOUT INCIDENT. MAINTENANCE FOUND AIR LEAK IN STATIC SYSTEM. TIGHTENED B-NUT ON LINE CROSS FITTING BEHIND F/O'S INSTRUMENT PANEL. OPERATION CHECK AND LEAK CHECK OF NR 2 PITOT/STATIC SYSTEM SATISFACTORY. AIRCRAFT RETURNED TO SERVICE. (X)