Air carrier with dtw TRACON described a confused frequency change assignment by ATC resulting a miss...

Narrative:

Our flight was getting vectored for the ILS 21L dtw. ATC issued a frequency change; the pilot not flying acknowledged the new frequency; then the same controller issued what sounded like a heading change just as we changed to the new assigned frequency. I told the pilot not flying that I thought I'd heard ATC give us a new clearance. The pilot not flying went back to the previous frequency and just said; 'roger'; then changed to the new frequency and asked the new controller what our last clearance had been from the previous controller. The new controller gave us a heading change to 330 degrees. It would have been a lot simpler for the pilot not flying to have asked the controller who originally gave us the frequency change; 'say again.' and it would have been better for ATC not to issue a new clearance after the frequency change read back when the frequencies are in the process of being swapped.

Original NASA ASRS Text

Title: Air Carrier with DTW TRACON described a confused frequency change assignment by ATC resulting a missed turn instruction; the reporter indicating both the crew members and ATC should have follow up the clearance to insure clarity.

Narrative: Our flight was getting vectored for the ILS 21L DTW. ATC issued a frequency change; the pilot not flying acknowledged the new frequency; then the same Controller issued what sounded like a heading change just as we changed to the new assigned frequency. I told the pilot not flying that I thought I'd heard ATC give us a new clearance. The pilot not flying went back to the previous frequency and just said; 'Roger'; then changed to the new frequency and asked the new Controller what our last clearance had been from the previous Controller. The new Controller gave us a heading change to 330 degrees. It would have been a lot simpler for the pilot not flying to have asked the Controller who originally gave us the frequency change; 'Say again.' And it would have been better for ATC not to issue a new clearance after the frequency change read back when the frequencies are in the process of being swapped.

Data retrieved from NASA's ASRS site as of April 2012 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.

Attributes
ACN	985524
Time
Date	201112
Local Time Of Day	1801-2400
Place
Locale Reference	DTW.Airport
State Reference	MI
Environment
Flight Conditions	IMC
Aircraft 1
Make Model Name	Regional Jet CL65 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Descent
Person 1
Function	Captain Pilot Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Events
Anomaly	ATC Issue All Types

Air carrier with dtw TRACON described a confused frequency change assignment by ATC resulting a missed turn instruction; the reporter indicating both the crew members and ATC should have follow up the clearance to insure clarity.