NEW CAPT TURNS TOO TIGHT AND NOSEWHEEL CASTORS. ACFT WAS TOWED AND INSPECTED.

Narrative

THE CAPT AND I BOTH MENTIONED THE POOR TURNING PERFORMANCE OF THE MD88. THE CAPT WHO WAS A LOW TIME CAPT ON THE MD88 ALSO MENTIONED THIS WAS A NEW EXPERIENCE FOR HIM; AS HE HAD NEVER BACK-TAXIED AND PERFORMED A 180 DEG TURN AT THE END OF THE RWY. APCHING THE FAR EDGE OF RWY 27R AT A SLOW TAXI SPD; THE CAPT BEGAN A SHARP L TURN ON THE TILLER. THE NOSE INITIALLY STARTED TRACKING L; THEN THE WHOLE NOSE BEGAN SHUDDERING AND THE NOSE VECTOR STOPPED TRACKING L. I YELLED 'WHOA; WHOA; WHOA!' AS I FELT THE NOSEWHEEL WAS ABOUT TO DEPART THE CONCRETE SURFACE FOR THE PAVED SHOULDER. A B757 CREW OBSERVED THAT OUR NOSEWHEEL WAS TURNED ABOUT 120 DEGS. WE OPTED TO SET THE PARKING BRAKE AND REQUESTED A TUG. A TUG CREW STRAIGHTENED THE NOSEWHEEL AND RETURNED THE ACFT TO THE GATE WHERE IT WAS INSPECTED AND LATER RETURNED TO SVC. WHILE HOLDING IN POS ON THE SECOND TAXI OUT; WE OBSERVED THAT THE NOSEWHEEL HAD SLIPPED ACROSS THE GROOVED AND PAINTED RWY SURFACE ALLOWING IT TO CASTOR. WE OBSERVED SKID MARKS PARALLEL TO THE GROOVES AND ACROSS A FAIR AMOUNT OF PAINTED SURFACE. THE MAINT INSPECTORS MENTIONED THAT IT IS NOT DIFFICULT TO CASTOR AN MD88 NOSEWHEEL AND IT IS COMMON FOR ONLY ONE OF THE 2 NOSEWHEELS TO BE IN CONTACT WITH THE PAVEMENT DURING MOST SHARP TURNS. BECAUSE OF THE DESIGN SHORTCOMINGS AND RELATIVE EASE WITH WHICH THE NOSEWHEEL ON THE MD88 CAN CASTOR; PERHAPS IT WOULD BE PRUDENT TO ESPECIALLY EMPHASIZE THIS ON IOE'S WITH FIRST-TIME CAPTS AND FO'S.