Narrative:

Air carrier flight # from mci to mhk with first officer as PF. We were being radar vectored for the ILS 3 approach at mhk with 6000 ft the assigned altitude by ZKC. The localizer frequency was in use on both captain and first officer radios with mhk VOR in standby on both and also giving us DME readouts. At 13.8 DME a different controller suddenly came on and told us to intercept the 13.0 DME arc for the ILS. In the turn, the first officer as PF descended 450 ft below the assigned altitude and then promptly recovered. It was apparent the first officer was trying to do too much all at the same time, i.e., turning to intercept a rapidly approaching clearance limit traveling at 250 KTS, switching the frequency from standby to use as well as switching the DME. As the PNF, I would have tuned the radios for the first officer but was still responding to ATC when the descent occurred. Although the altitude bust did occur, it was clearly the fault of the controller. If they profess to adhering to practices that promote and maintain a safe air traffic system, they should not spring surprises onto the flcs. We went from being radar vectored for the approach by a male controller to being told to intercept the arc by a female controller when we were upon that 13 NM limit with absolutely no forewarning. Evidently, there was a shift change because that was the very first transmission by the female voice which in itself caused us to do a 'double take' as we were not attuned to hearing that particular voice give us instructions on this leg. We had previously been into mhk that day as flight # and were vectored for the ILS 3 with no incident. The late abrupt departure from normal procedure by the controller further compounded the flight crew's ability to react ('turn on a dime').

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Original NASA ASRS Text

Title: FO OF ACR LTT ACFT ALLOWED THE ACFT TO DSND BELOW ASSIGNED APCH VECTORING ALT DURING A TURN TO FINAL.

Narrative: ACR FLT # FROM MCI TO MHK WITH FO AS PF. WE WERE BEING RADAR VECTORED FOR THE ILS 3 APCH AT MHK WITH 6000 FT THE ASSIGNED ALT BY ZKC. THE LOC FREQ WAS IN USE ON BOTH CAPT AND FO RADIOS WITH MHK VOR IN STANDBY ON BOTH AND ALSO GIVING US DME READOUTS. AT 13.8 DME A DIFFERENT CTLR SUDDENLY CAME ON AND TOLD US TO INTERCEPT THE 13.0 DME ARC FOR THE ILS. IN THE TURN, THE FO AS PF DSNDED 450 FT BELOW THE ASSIGNED ALT AND THEN PROMPTLY RECOVERED. IT WAS APPARENT THE FO WAS TRYING TO DO TOO MUCH ALL AT THE SAME TIME, I.E., TURNING TO INTERCEPT A RAPIDLY APCHING CLRNC LIMIT TRAVELING AT 250 KTS, SWITCHING THE FREQ FROM STANDBY TO USE AS WELL AS SWITCHING THE DME. AS THE PNF, I WOULD HAVE TUNED THE RADIOS FOR THE FO BUT WAS STILL RESPONDING TO ATC WHEN THE DSCNT OCCURRED. ALTHOUGH THE ALT BUST DID OCCUR, IT WAS CLRLY THE FAULT OF THE CTLR. IF THEY PROFESS TO ADHERING TO PRACTICES THAT PROMOTE AND MAINTAIN A SAFE AIR TFC SYS, THEY SHOULD NOT SPRING SURPRISES ONTO THE FLCS. WE WENT FROM BEING RADAR VECTORED FOR THE APCH BY A MALE CTLR TO BEING TOLD TO INTERCEPT THE ARC BY A FEMALE CTLR WHEN WE WERE UPON THAT 13 NM LIMIT WITH ABSOLUTELY NO FOREWARNING. EVIDENTLY, THERE WAS A SHIFT CHANGE BECAUSE THAT WAS THE VERY FIRST XMISSION BY THE FEMALE VOICE WHICH IN ITSELF CAUSED US TO DO A 'DOUBLE TAKE' AS WE WERE NOT ATTUNED TO HEARING THAT PARTICULAR VOICE GIVE US INSTRUCTIONS ON THIS LEG. WE HAD PREVIOUSLY BEEN INTO MHK THAT DAY AS FLT # AND WERE VECTORED FOR THE ILS 3 WITH NO INCIDENT. THE LATE ABRUPT DEP FROM NORMAL PROC BY THE CTLR FURTHER COMPOUNDED THE FLC'S ABILITY TO REACT ('TURN ON A DIME').

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.