RELYING ON A GND MARSHALER AN SF34 ENDS UP STUCK IN SOFT GND AFTER LEAVING THE HARD SURFACE AREA OF A CRAMPED RAMP. COMPLIANCE WITH COMPANY POLICY IS CITED AS CONTRIBUTING TO THIS RECURRING PROB.

Narrative

OUR COMPANY USES GA SIZE HANGAR AND RAMP TO MAINTAIN AND PARK SAAB 340'S AND BEECH 1900'S. AS A RESULT; MAINT PARKS ONE OF THE SAAB'S WITH ITS MAIN GEAR AS FAR BACK ON ASPHALT SURFACE AS POSSIBLE; WITH TAIL HANGING OVER GRASS. RAMP SURFACE HAS NO PAINTED EDGE STRIPES; AND NO ILLUMINATION EXCEPT LIGHTS SHINING FROM HANGAR. ACFT FUSELAGE BLOCKS LIGHT FROM HANGAR MAKING IT VERY DIFFICULT TO POSITIVELY IDENT RELATION OF R MAIN TIRES TO THE EDGE OF ASPHALT RAMP. UPON COMPLETION OF AFTER START CHKLIST; FLASHED TAXI LIGHT TO MARSHALER (MAINT EMPLOYEE) AS AN INDICATION WE WERE READY TO DEPART RAMP. FOLLOWED MARSHALERS SIGNALS AND FELT R MAIN WHEELS SINKING. RETARDED PWR LEVERS; SIMULTANEOUSLY RECEIVED CROSSED WANDS INDICATING WE SHOULD STOP. COMPLETED PARKING CHKLIST AND EXITED ACFT TO DISCOVER R MAIN HAD BEEN OFF THE RAMP FOR APPROX 6-8 FT BEFORE SINKING INTO SOFT GND. LATER FOUND OUT THAT WAS THE THIRD TIME IT HAS HAPPENED IN RECENT MONTHS AND MAINT PERSONNEL WERE NOT FOLLOWING GUIDANCE DICTATED BY DIRECTOR OF SAFETY.