Cpr X readback wrong altitude.

Attributes
ACN	172093
Time
Date	199103
Day	Tue
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : jli
State Reference	CA
Altitude	msl bound lower : 16000 msl bound upper : 16000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zla
Operator	general aviation : corporate
Make Model Name	Small Transport, Low Wing, 2 Turboprop Eng
Flight Phase	descent other
Route In Use	enroute : direct
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : radar
Qualification	controller : radar
Experience	controller military : 4 controller radar : 22
ASRS Report	172093
Person 2
Affiliation	Other
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	other anomaly other
Independent Detector	other controllera
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	other

Narrative:

X was given a clearance to descend and maintain 16000'. The pilot read back descend and maintain 12000'. The problem was I had traffic for him at 15000', so I reiterated the clearance to descend and maintain 16000'. This time the pilot copied and read back descend and maintain 16000'. This pilot flies the route daily sometime more than once a day and 99 percent of the time the clearance he receives is descend and maintain 12000' thus I am sure this is what he expected to hear and so he heard it. We, all pilots and controllers, have to actively listen.

Original NASA ASRS Text

Title: CPR X READBACK WRONG ALT.

Narrative: X WAS GIVEN A CLRNC TO DSND AND MAINTAIN 16000'. THE PLT READ BACK DSND AND MAINTAIN 12000'. THE PROB WAS I HAD TFC FOR HIM AT 15000', SO I REITERATED THE CLRNC TO DSND AND MAINTAIN 16000'. THIS TIME THE PLT COPIED AND READ BACK DSND AND MAINTAIN 16000'. THIS PLT FLIES THE RTE DAILY SOMETIME MORE THAN ONCE A DAY AND 99 PERCENT OF THE TIME THE CLRNC HE RECEIVES IS DSND AND MAINTAIN 12000' THUS I AM SURE THIS IS WHAT HE EXPECTED TO HEAR AND SO HE HEARD IT. WE, ALL PLTS AND CTLRS, HAVE TO ACTIVELY LISTEN.

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.