Flight crew confusion over clearance interpretation and possible altitude deviation altitude oversho...

Attributes
ACN	355360
Time
Date	199612
Day	Sat
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : jvl airport : ord
State Reference	WI
Altitude	msl bound lower : 6000 msl bound upper : 7000
Environment
Light	Night
Aircraft 1
Controlling Facilities	artcc : zau
Operator	common carrier : air carrier
Make Model Name	B727 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	descent other
Route In Use	arrival other enroute : on vectors
Flight Plan	IFR
Aircraft 2
Make Model Name	Fokker 100
Operating Under FAR Part	Part 121
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	355360
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
ASRS Report	355427
Events
Anomaly	altitude deviation : overshoot non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other Other
Supplementary
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Deviation other

Narrative:

ATC facility: ZAU. Location: northwest of ord, level at 10000 ft, just past jvl when we were given a turn to 140 degrees and descend to 6000 ft. At 6500 ft the center told us again to level at 6000 ft. Then about 30 seconds later he told us that we had traffic at 5000 ft below us. Then he told us we were instructed to level at 7000 ft at first. We acknowledged the turn to 140 degrees and the descent to 6000 ft and he confirmed it. This was the first time we had heard anything about 7000 ft. The controllers then changed and nothing else was said.

Original NASA ASRS Text

Title: FLC CONFUSION OVER CLRNC INTERP AND POSSIBLE ALTDEV ALT OVERSHOT IN DSCNT.

Narrative: ATC FACILITY: ZAU. LOCATION: NW OF ORD, LEVEL AT 10000 FT, JUST PAST JVL WHEN WE WERE GIVEN A TURN TO 140 DEGS AND DSND TO 6000 FT. AT 6500 FT THE CTR TOLD US AGAIN TO LEVEL AT 6000 FT. THEN ABOUT 30 SECONDS LATER HE TOLD US THAT WE HAD TFC AT 5000 FT BELOW US. THEN HE TOLD US WE WERE INSTRUCTED TO LEVEL AT 7000 FT AT FIRST. WE ACKNOWLEDGED THE TURN TO 140 DEGS AND THE DSCNT TO 6000 FT AND HE CONFIRMED IT. THIS WAS THE FIRST TIME WE HAD HEARD ANYTHING ABOUT 7000 FT. THE CTLRS THEN CHANGED AND NOTHING ELSE WAS SAID.

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.

Flight crew confusion over clearance interpretation and possible altitude deviation altitude overshot in descent.