ZAU describes situation where he did not hear the initial call up with altitude and assumed the airc...

Attributes
ACN	1175818
Time
Date	201405
Local Time Of Day	1201-1800
Place
Locale Reference	ZAU.ARTCC
State Reference	IL
Environment
Light	Daylight
Aircraft 1
Make Model Name	Small Transport Low Wing 2 Turbojet Eng
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Flight Plan	IFR
Person 1
Function	Enroute
Qualification	Air Traffic Control Fully Certified
Experience	Air Traffic Control Time Certified In Pos 1 (mon) 7
Events
Anomaly	ATC Issue All Types Aircraft Equipment Problem Less Severe Airspace Violation All Types Deviation - Procedural Published Material / Policy

Narrative:

After listening to the recording; it appears that this aircraft had a faulty mode C. His altitude showed he was level at FL320 in the previous sector; then his mode C showed him at FL375 and someone changed his data block to a hard altitude of FL380. I never saw any of this. When I took the handoff; I observed him at FL376; I assumed he was climbing to FL380. When the aircraft checked on to my frequency; I missed the initial call that he was level at FL320. I flashed the aircraft to the sector 71 (alo); the data block autos flashed to 76 (arl). However; I technically violated the 75 (coton) sector since the aircraft was at FL320. We didn't have any other aircraft in the vicinity; so luckily we didn't have a situation; nevertheless; this is a major concern. Active listening and not assuming you hear what the data block says.

Original NASA ASRS Text

Title: ZAU describes situation where he did not hear the initial call up with altitude and assumed the aircraft was doing what he thought it should be doing; when it wasn't.

Narrative: After listening to the recording; it appears that this aircraft had a faulty Mode C. His altitude showed he was level at FL320 in the previous sector; then his Mode C showed him at FL375 and someone changed his data block to a hard altitude of FL380. I never saw any of this. When I took the handoff; I observed him at FL376; I assumed he was climbing to FL380. When the aircraft checked on to my frequency; I missed the initial call that he was level at FL320. I flashed the aircraft to the sector 71 (ALO); the data block autos flashed to 76 (ARL). However; I technically violated the 75 (COTON) sector since the aircraft was at FL320. We didn't have any other aircraft in the vicinity; so luckily we didn't have a situation; nevertheless; this is a major concern. Active listening and not assuming you hear what the data block says.

Data retrieved from NASA's ASRS site 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.