CFI ON A PRACTICE INST FLT IN IFR WX OVERSHOOTS MISSED APCH ALT.

Narrative

DURING AN IFR PROFICIENCY FLT; PRACTICING APCHS IN IMC AT 2 NEARBY ARPTS; A SIGNIFICANT HEADING AND ALTDEV OCCURRED WHILE BEING VECTORED FOR THE LAST OF 3 APCHS. ON THE SECOND APCH; SEVERAL ALTS AND HEADINGS WERE GIVEN BEFORE ANY WERE REACHED; ENDING WITH 3000 FT AND 240 DEGS 'CLRED FOR THE ILS RWY 27' WITH NO MISSED APCH INSTRUCTIONS. ON THE MISSED; WITH NO OTHER INSTRUCTIONS; WE BEGAN THE PUBLISHED MISSED; 'DIRECT TO THE VOR; CLB TO 2500 FT.' WHILE CLBING THROUGH 1600 FT; WE RECEIVED A 'FLY 270' INSTRUCTION. WE MADE 3 CALLS REQUESTING AN ASSIGNED ALT. SINCE THE MINIMUM SECTOR ALT FOR BOTH THE PRIOR APCH AND THE NEXT IS 3000 FT; WE DECIDED TO CONTINUE TO 3000 FT; FROM ABOUT 2000 FT. FINALLY ON THE THIRD CALL; AT 2600 FT; WE RECEIVED 'FLY 270 DEGS MAINTAIN 2500 FT.' WHILE TRYING TO ARREST THE CLB AND RETURN TO 2500 FT; WE DSNDED BELOW 2200 FT. WE ALSO RECEIVED A NEW HEADING DURING THAT TIME WHICH WE ENDED UP OVERSHOOTING BY 30 DEGS. THE FINAL HEADING WAS GIVEN WITHIN 4 MI OF THE FAF; SO WE WERE ALSO CHANGING CONFIGN TO APCH AND REPROGRAMMING THE GPS FOR VECTORS TO FINAL. IN ADDITION; THE PAX (AN INST RATED PVT PLT) RESET THE OBS WITHOUT THE PLT'S TUNING THE VOR FREQ -- ACTUALLY A DISTR; SINCE THE VOR WAS NOT THE MAIN NAV RADIO FOR THE GPS APCH. I DID RETUNE THE VOR FOR XCHK AFTER THAT; A FURTHER; UNNECESSARY DISTR WHEN THINGS WERE ALREADY UNSTABLE. WHILE CORRECTING ALL THIS; APCH CTL CALLED WITH 'MAINTAIN 2500 FT' AND A NEW VECTOR TO FINAL; WHICH WE DID. THEREAFTER; THE APCH WENT WELL. FACTORS I BELIEVE CONTRIBUTED TO THIS EXCURSION ARE: CONFUSION ABOUT THE ALT AFTER VECTORS WERE ISSUED ON THE MISSED. LATE INSTRUCTION ON ALT; REQUIRING IMMEDIATE DSCNT FROM CLB. LATE VECTOR TO FINAL COURSE; REQUIRING IMMEDIATE CONFIGN CHANGE. PLT'S FAILURE TO ANTICIPATE CTL'S INSTRUCTIONS AFTER STARTING VECTORS. DISTR BY PAX CALLING ATTN TO VOR INDICATOR NOT IN USE. DISTR OF REPROGRAMMING GPS FOR VECTORS TO FINAL WITHIN 2 MINS OF FAF. WHAT WOULD I DO DIFFERENTLY NEXT TIME? ASK FOR FULL APCH; WHICH WOULD HAVE PROVIDED TIME PRIOR TO THE APCH TO STABILIZE ALT AND CHANGE CONFIGN DURING FLT TO THE VOR (WAYPOINT) THEN TO THE FAF. EVEN EARLIER; NOT PLAN PRACTICE APCHS IN IMC WITH SO LITTLE TRANSITION TIME WHEN USING A HIGH PERFORMANCE ACFT.