Narrative:

3RD leg of day on aircraft; captain PNF; copilot PF. Visual approach ZZZ runway 29; everything normal during approach and touchdown; landing gear horn starts to sound during rollout (all 3 gear on ground; weight on wheels; less than 80 KTS) and left main gear lights start to flicker between green and red. As aircraft slows to speed slow enough to turn on 90 degrees taxi connector; left main landing gear light goes solid red; horn still sounding. Captain makes turn on connector; and taxies straight into non-movement ramp ahead and stops. Parking brake set and aircraft shut down. Upon examination of left main landing gear wheel well; the outboard trunnion pin was found missing; left main landing gear was found slightly askew; but still attached by opposite pin. Preflight inspection discovered no anomaly; but neither crew member remembers looking specifically at the bat that is the safety on the trunnion pin. (Procedure does not specifically say to do so; although it would be good practice) because of normal operation of gear during the flight; except rollout; the crew thinks that the pin might be on the runway in ZZZ. Airport operations was contacted; a vehicle dispatched with aircrew and airport operations onboard; and trunnion pin found on runway near taxiway A5 almost to edge of grass/pavement on left side. Maintenance contacted; aircraft repaired and ferried back to ZZZ1 for further inspection.

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Original NASA ASRS Text

Title: SA-227 FLT CREW EXPERIENCED UNSAFE LNDG GEAR WARNING DURING LNDG ROLLOUT. AFTER TAXIING CLEAR OF RUNWAY; TRUNNION PIN IS DISCOVERED TO BE MISSING.

Narrative: 3RD LEG OF DAY ON ACFT; CAPT PNF; COPLT PF. VISUAL APCH ZZZ RWY 29; EVERYTHING NORMAL DURING APCH AND TOUCHDOWN; LNDG GEAR HORN STARTS TO SOUND DURING ROLLOUT (ALL 3 GEAR ON GND; WT ON WHEELS; LESS THAN 80 KTS) AND L MAIN GEAR LIGHTS START TO FLICKER BTWN GREEN AND RED. AS ACFT SLOWS TO SPD SLOW ENOUGH TO TURN ON 90 DEGS TAXI CONNECTOR; L MAIN LNDG GEAR LIGHT GOES SOLID RED; HORN STILL SOUNDING. CAPT MAKES TURN ON CONNECTOR; AND TAXIES STRAIGHT INTO NON-MOVEMENT RAMP AHEAD AND STOPS. PARKING BRAKE SET AND ACFT SHUT DOWN. UPON EXAM OF L MAIN LNDG GEAR WHEEL WELL; THE OUTBOARD TRUNNION PIN WAS FOUND MISSING; L MAIN LNDG GEAR WAS FOUND SLIGHTLY ASKEW; BUT STILL ATTACHED BY OPPOSITE PIN. PREFLT INSPECTION DISCOVERED NO ANOMALY; BUT NEITHER CREW MEMBER REMEMBERS LOOKING SPECIFICALLY AT THE BAT THAT IS THE SAFETY ON THE TRUNNION PIN. (PROC DOES NOT SPECIFICALLY SAY TO DO SO; ALTHOUGH IT WOULD BE GOOD PRACTICE) BECAUSE OF NORMAL OP OF GEAR DURING THE FLT; EXCEPT ROLLOUT; THE CREW THINKS THAT THE PIN MIGHT BE ON THE RWY IN ZZZ. ARPT OPS WAS CONTACTED; A VEHICLE DISPATCHED WITH AIRCREW AND ARPT OPS ONBOARD; AND TRUNNION PIN FOUND ON RWY NEAR TXWY A5 ALMOST TO EDGE OF GRASS/PAVEMENT ON L SIDE. MAINT CONTACTED; ACFT REPAIRED AND FERRIED BACK TO ZZZ1 FOR FURTHER INSPECTION.

Data retrieved from NASA's ASRS site as of January 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.