A B727 FREIGHTER WAS DISPATCHED IN NON COMPLIANCE WITH THE INCORRECT AIRSPD WARNING SWITCHES INSTALLED DUE TO MAINT MANUAL AND WIRE DIAGRAM MANUAL CONFLICT.

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ON JAN/XA/01; ACFT XYZ ARRIVED IN ZZZ WITH A REPEAT WRITE-UP CONCERNING ITS MACH WARNING SYS: LOG # YVX ITEM 1P: 'DURING DSCNT CLACKERS SOUNDED AT 310 KTS. RED LINE FLAG WAS AT 330 KTS ALT WAS FL330. REF LOG PAGE WXO.' CORRECTIVE ACTION READS AS FOLLOWS: 'PERFORMED MACH WARNING CHK PER MAINT MANUAL; FOUND BOTH SWITCHES GOING OFF AT 350 KTS. INSPECTED SWITCH PINS AND FOUND AN ABCD-3 INSTALLED IN THE 'B' MODE (#2 SWITCH) POS. PER MAINT MANUAL; A SWITCH ABCD-5 REQUIRED. RETURNED SWITCH; REPERFORMED TEST. BOTH SWITCHES STILL GOING OFF AT 350 KTS. SUGGEST R RING 'A' MODE (#1 SWITCH). A MODE SWITCH DEFERRED PER MEL DMI #YYY. REQUIRED INSPECTION ITEM AND AIRWORTHINESS SIGNED OFF. UPON RETURN TO WORK ON THE EVENING OF JAN/XD/01 I FOUND THAT IT HAD BEEN DETERMINED THAT PER THE MASTER EQUIP LIST AND WIRING DIAGRAMS; THE SWITCH PART NUMBERS REQUIRED FOR ACFT XYZ ARE BOTH PART NUMBER ABCD-3. HOWEVER; I CHKED IN BOTH THE ACR BOEING 727 MAINT MANUAL AND THE ORIGINAL BOEING MAINT MANUAL WHICH COME WITH ACFT XYZ AND PER MAINT MANUAL THE MACH AIRSPD SWITCH #1 PINS PART #ABCD-3 AND THE MACH AIRSPD SWITCH #2 IS PIN ABCD-5. THE OUTSTATION REMOVED AND REPLACED THE #2 MACH WARNING SWITCH PART #ABCD-5 WHICH HAD BEEN INSTALLED AND REINSTALLED ON PART #ABCD-3 IN THAT POS. I SIGNED OFF THE AIRWORTHINESS AND REQUIRED INSPECTION ITEM WHILE ANOTHER MECH SIGNED OFF THE ACTUAL ITEM. MY CONCERN IS THAT WE FOLLOWED THE MAINT MANUAL FOR SWITCH PART NUMBER BUT THE IPC AND WIRING DIAGRAM CALLED FOR A DIFFERENT NUMBER. THIS IS A CONTINUAL PROB WITH OUR MANUALS DUE TO THE MANY DIFFERENT VARIATIONS OF B727 ACR ACFT. THE ACFT DEVIATE FROM WHAT THE MAINT MANUAL CALLS OUT AND THE WIRING DIAGRAMS DIFFER FROM THE MAINT MANUALS.