LAX85LA108

Factual narrative

DURING FIRST LEG OF THE FLIGHT, PLT DISCOVERED THAT LANDING GEAR WOULD NOT EXTEND. PRESSURIZING 'DOWN SIDE' WITH EMERGENCY HAND PUMP ALLOWED NORMAL OPERATION OF THE LANDING GEAR. ON RETURN FLT TO SAN JOSE, PLT TRIED TO EXTEND THE GEAR BUT SYSTEM WOULD NOT WORK WITH EITHER THE NORMAL OR EMERGENCY SYSTEM. ACFT LANDED GEAR UP AND INCURRED SUBSTANTIAL DAMAGE. SUBSEQUENT EXAMINATION OF THE HYDRAULIC SYSTEM DISCLOSED A ONE-HALF INCH PIECE OF PACKING IN THE NOSE GEAR MANIFOLD NEAR THE DOOR CLOSE VALVE, AND A THERMAL RELIEF VALVE STUCK IN THE OPEN POSITION BY A BUILD-UP OF 'DARK COLORED GREASY RESIDUE' ON THE SPRING. Source: NTSB Aviation Accident Database (Pre-2008 Archive) Retrieved: 2026-02-12