Clearance interpretation problem, hearback problem with ord approach control. Heading deviation.

Attributes
ACN	307450
Time
Date	199506
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	airport : ord
State Reference	IL
Environment
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ord
Operator	common carrier : air carrier
Make Model Name	MD-80 Super 80
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	cruise other descent : approach
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
ASRS Report	307450
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	non adherence : clearance other anomaly other other spatial deviation
Independent Detector	other flight crewa
Resolutory Action	controller : issued new clearance flight crew : became reoriented flight crew : returned to intended course or assigned course
Consequence	Other
Supplementary
Primary Problem	Ambiguous
Air Traffic Incident	Pilot Deviation
Situations
ATC Facility	procedure or policy : unspecified

Narrative:

Controller missed readback. While downwind for runway 14R, approach issued a heading change that was partially blocked...turn right 040 degrees. Right 340 degrees was read back. 30 seconds later we asked to verify the heading, approach replied I do not know, what heading were you issued. We replied we think it was 340 degrees, he said no turn right 040 degrees and intercept the localizer, speed up to FL210 to the marker. We completed the approach uneventfully. We depend on readbacks to verify various instructions. Many times ATC appears too busy to listen to the readback. In this case it appeared to be no big deal, but what if approach was in its usual over-tasked mode.

Original NASA ASRS Text

Title: CLRNC INTERP PROB, HEARBACK PROB WITH ORD APCH CTL. HDG DEV.

Narrative: CTLR MISSED READBACK. WHILE DOWNWIND FOR RWY 14R, APCH ISSUED A HDG CHANGE THAT WAS PARTIALLY BLOCKED...TURN R 040 DEGS. R 340 DEGS WAS READ BACK. 30 SECONDS LATER WE ASKED TO VERIFY THE HDG, APCH REPLIED I DO NOT KNOW, WHAT HDG WERE YOU ISSUED. WE REPLIED WE THINK IT WAS 340 DEGS, HE SAID NO TURN R 040 DEGS AND INTERCEPT THE LOC, SPD UP TO FL210 TO THE MARKER. WE COMPLETED THE APCH UNEVENTFULLY. WE DEPEND ON READBACKS TO VERIFY VARIOUS INSTRUCTIONS. MANY TIMES ATC APPEARS TOO BUSY TO LISTEN TO THE READBACK. IN THIS CASE IT APPEARED TO BE NO BIG DEAL, BUT WHAT IF APCH WAS IN ITS USUAL OVER-TASKED MODE.

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.