A B737-300 ON LNDG WAS UNABLE TO OBTAIN REVERSE THRUST ON EITHER ENG DUE TO THE THRUST LEVERS BLOCKED AT IDLE CAUSED BY AN IMPROPERLY INSTALLED SWITCH MOUNTING PANEL.

Narrative

THE PANEL WAS INSTALLED UPSIDE DOWN. THERE IS REALLY NO WAY OF TELLING WHICH SIDE IS THE RIGHT SIDE UP. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THE LNDG GEAR WARNING HORN CUTOUT SWITCH IS LOCATED ON THE PEDESTAL ADJACENT TO THE R THRUST LEVER AND IS MOUNTED TO A SMALL PANEL FASTENED TO THE THROTTLE QUADRANT. THE RPTR SAID THE SWITCH WAS REPLACED ON THE PANEL AND THE PANEL AND SWITCH ASSEMBLY WAS REINSTALLED ON THE THROTTLE QUADRANT. THE RPTR STATED THE GEAR WARNING WAS TESTED AND THE CUTOUT SWITCH CHKED OK. THE RPTR SAID THE ACFT WAS DISPATCHED AND ON THE FIRST LNDG THE CREW WAS UNABLE TO GET THE ENGS INTO REVERSE THRUST. THE RPTR STATED THE SWITCH MOUNTING PANEL WAS INSTALLED UPSIDE DOWN INTERFERING WITH THE THRUST LEVERS AT IDLE. THE RPTR STATED THE PANEL CAN BE INSTALLED IN ANY POS AND THE FASTENERS WILL BE ALIGNED AND NO INDICATION WAS ON THE PANEL FOR FORE OR AFT ORIENTATION. THE RPTR SAID THE MAINT MANUAL DOES NOT ADDRESS THE SWITCH INSTALLATION ONLY THE CHK OF THE SYS. THE RPTR STATED THE FAA HAS MADE NO CONTACT WITH THE RPTR.