ACR CONFUSES CTLR INSTRUCTION DURING IN COCKPIT TRAINING AND FAILS TO LEVEL AT CLRED ALT.

Narrative

ON DSCNT INTO CLT FROM NE; APCHING MAYOS INTXN FROM NE; WE WERE CLRED AS FOLLOWS: ACFT X IS CLRED TO FL240 AND PLAN YOUR DSCNT SO AS TO CROSS MAYOS AT FL220. THE PF DIALED FL240 INTO THE ALT WINDOW AND BOTH THE PF AND PNF MADE STANDARD ALT CALLOUTS AS PER COMPANY PROC. DURING THE DSCNT; THE PF CHANGED THE ALT IN THE ALT WINDOW AND THIS WAS NOT NOTICED BY THE PNF (CAPT). REQUIRED ALT ACKNOWLEDGEMENTS WERE NOT MADE. AS A RESULT; THE ACFT DSNDED THROUGH FL240 AND WAS NOTED AT FL230 BY ATC. ATC IMMEDIATELY CLRED ACFT TO FL220 AND STATED THAT NO LOSS OF SEPARATION OCCURRED. ASSESSMENT: 1) ACFT DSNDED THROUGH FL240 AS ASSIGNED BECAUSE NEW ALT WAS SET IN ALT WINDOW AND PROPER AND REQUIRED ALT ACKNOWLEDGEMENTS WERE NOT MADE. 2) PNF WAS NOT ADEQUATELY DILIGENT IN MAINTAINING ALT AWARENESS WHILE GIVING INSTRUCTION TO NEW HIRE PLT REGARDING LIMITATIONS OF ACFT'S FMS ON DSCNT AND TAILWIND. 3) COMPANY PROC OF POINT TO AND SAY NEW ALT IN ALT WINDOW WOULD HAVE PREVENTED THIS EVENT HAD IT BEEN ADHERED TO.