AN HS125-700 HAWKER CAPTAIN REPORTS OF A 'DIRTY SOCKS' SMELL IN THE COCKPIT AND PASSENGERS NOTICED SMOKE IN DOOR ENTRY AREA JUST PRIOR TO TAKEOFF.

Narrative

THIS WAS A REVENUE; PART 135; FLT IN A HAWKER 700. THE CREW CONSISTED OF MYSELF (DESIGNATED PIC) AND A COPLT. BOTH PLTS WERE TYPE RATED AND CURRENT IN TYPE. THE WX WAS GOOD (CLR WITH EXCELLENT VISIBILITY) THE TEMP WAS APPROX +5 DEGS C AND RWY CONDITIONS WERE DRY. 6 PAX AND THEIR BAGGAGE WERE ON BOARD FOR A RETURN TRIP TO ZZZ1. I COMMENTED TO THE COPLT THAT THE COCKPIT SMELLED LIKE 'DIRTY SOCKS' AS I ENTERED THE COCKPIT JUST BEFORE ENG START. FIGURING THE SOURCE OF THIS SMELL TO BE SWEAT RAGS THE PLTS USED DURING HOT WX AND STORED IN THE SIDE PLT POCKETS; I PAID NO MORE ATTN TO THE SMELL. ALL CHKLISTS FROM PREFLT TO TAXI HAD BEEN COMPLETED. NO ABNORMALITIES OR ANNUNCIATOR PANEL LIGHTS INDICATED A PROB. JUST BEFORE POWERING UP FOR TKOF AT THE END OF THE RWY; THE PAX CALLED OUT TO ME AND I TURNED AROUND TO FACE THEM AND IMMEDIATELY NOTICED A SMALL AMOUNT OF SMOKE IN THE ENTRY WAY (AIRSTAIR) AREA OF THE FLOOR. I IMMEDIATELY INSTRUCTED THE COPLT TO INFORM CTAF THAT WE WERE TERMINATING THE TKOF AND RETURNING TO THE RAMP. DURING RETURN TO THE TARMAC; BOTH THE COPLT AND ME CHKED FOR ANY INDICATIONS (ANNUNCIATOR LIGHT OR GAUGE) OF A PROB. NONE WERE NOTED. I STOPPED THE ACFT ONCE WE WERE CLR OF THE RWY (UNCTLED FIELD PRECAUTION); AND PROCEEDED TO DEPLANE THE PAX AS PER THE EMER CHKLIST MEMORY ITEMS. I SHUT DOWN THE ACFT AS PER THE CHKLIST; AS THE COPLT TOOK THE PAX BACK TO THE FBO. AS I DEPARTED THE ACFT; I DISCONNECTED THE MAIN SHIP BATTERIES AS AN ADDITIONAL PRECAUTION. THE COMPANY DISPATCH AND MAINT WERE CONTACTED; THE PAX WERE PROVIDED WITH ANOTHER FLT HOME. THE ACFT WAS REPAIRED AND THE PROB WAS DETERMINED TO BE IN THE ELECTRICAL CIRCUIT THAT PROVIDED PWR TO THE ENTRY AND EMER LIGHTING. SINCE THE PROB WAS CAUGHT RELATIVELY EARLY AND ON THE GND; PAX DISCOMFORT AND ACFT DAMAGE WAS MINIMAL. I BELIEVE THAT CREW TRAINING AND EXPERIENCE PLAYED A PIVOTAL ROLE IN RESOLVING THE SITUATION WITHOUT MAJOR PROBS. CREW UNDERSTANDING OF ACFT SYS AND PROCS FOR EMERS MINIMIZED PROBS AND LED TO A SAFE AND HAPPY ENDING FOR ALL. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: REPORTER STATED THIS ACFT DOES HAVE A 'TKS' ANTI-ICE SYSTEM WITH A FLUID RESERVOIR TANK BELOW THE DOOR ENTRY THRESHOLD. THE DAMAGED ELECTRICAL WIRE BUNDLE WAS ORIGINAL INSTALLATION AND WAS FOUND BY MAINT TO HAVE FUSED (MELTED) TOGETHER; PERHAPS FROM YEARS OF IN-FLIGHT TURBULENCE AND CHAFING. REPORTER ALSO STATED HE WASN'T SURE; BUT DIDN'T THINK THAT RESIDUAL FLUID FROM THE SERVICING OF THE ANTI-ICE FLUID RESERVOIR NECESSARILY CAUSED THE SHORTED WIRING. THIS ORIGINAL WIRE BUNDLE WAS NOT REPLACED DURING THE CABIN MOD UPGRADE; BUT CONTINUED IN USE PROVIDING POWER TO THE ENTRY DOOR AND EMERGENCY LIGHTING.