Two radar controller's failed to hear incorrect readback of wrong altitude. Operational deviation.

Attributes
ACN	167943
Time
Date	199101
Day	Fri
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : fax
State Reference	VA
Altitude	msl bound lower : 22000 msl bound upper : 20000
Environment
Flight Conditions	Mixed
Light	Night
Aircraft 1
Controlling Facilities	artcc : zdc artcc : zkc
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 160 flight time total : 14000 flight time type : 9000
ASRS Report	167943
Person 2
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : atp
Experience	flight time last 90 days : 50 flight time total : 4000
ASRS Report	167946
Events
Anomaly	altitude deviation : overshoot non adherence : published procedure non adherence : clearance
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	faa : reviewed incident with flight crew
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Intra Facility Coordination Failure

Narrative:

I was the captain of air carrier X and also the PNF. In the vicinity of flat rock VOR (fak) a clearance to descend to FL220 was issued by center. Our understanding was to FL200 and read back and set FL200 in the aircraft's altitude alert. The controller did not catch the discrepancy in the readback. We then received a frequency change and upon checking in on the next frequency stated we were descending to FL200. At approximately FL20.8 the controller instructed us to stop descent immediately as we were only cleared to FL220. He also (or she) failed to catch the altitude discrepancy during our initial check-in. We were then cleared to maintain FL200. His concern was traffic at FL190. It is my understanding that no sep was lost. This was a clear communication problem and two opportunities to be caught were missed. I feel closer verification of readbacks would have caught this verbal error. Supplemental information from acn 167946. The controller confessed it had been a multiple of errors: we had been cleared to FL200 but that they normally received aircraft descending to FL220 and the concern had been for traffic below at FL190.

Original NASA ASRS Text

Title: TWO RADAR CTLR'S FAILED TO HEAR INCORRECT READBACK OF WRONG ALT. OPDEV.

Narrative: I WAS THE CAPT OF ACR X AND ALSO THE PNF. IN THE VICINITY OF FLAT ROCK VOR (FAK) A CLRNC TO DSND TO FL220 WAS ISSUED BY CTR. OUR UNDERSTANDING WAS TO FL200 AND READ BACK AND SET FL200 IN THE ACFT'S ALT ALERT. THE CTLR DID NOT CATCH THE DISCREPANCY IN THE READBACK. WE THEN RECEIVED A FREQ CHANGE AND UPON CHKING IN ON THE NEXT FREQ STATED WE WERE DSNDING TO FL200. AT APPROX FL20.8 THE CTLR INSTRUCTED US TO STOP DSNT IMMEDIATELY AS WE WERE ONLY CLRED TO FL220. HE ALSO (OR SHE) FAILED TO CATCH THE ALT DISCREPANCY DURING OUR INITIAL CHK-IN. WE WERE THEN CLRED TO MAINTAIN FL200. HIS CONCERN WAS TFC AT FL190. IT IS MY UNDERSTANDING THAT NO SEP WAS LOST. THIS WAS A CLR COM PROB AND TWO OPPORTUNITIES TO BE CAUGHT WERE MISSED. I FEEL CLOSER VERIFICATION OF READBACKS WOULD HAVE CAUGHT THIS VERBAL ERROR. SUPPLEMENTAL INFO FROM ACN 167946. THE CTLR CONFESSED IT HAD BEEN A MULTIPLE OF ERRORS: WE HAD BEEN CLRED TO FL200 BUT THAT THEY NORMALLY RECEIVED ACFT DSNDING TO FL220 AND THE CONCERN HAD BEEN FOR TFC BELOW AT FL190.

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.