B757 crew inbound to sna is cleared on the kayoh arrival and starts descent without approval.

Attributes
ACN	570567
Time
Date	200301
Day	Tue
Local Time Of Day	1801 To 2400
Place
Locale Reference	intersection : dejay
State Reference	CA
Altitude	msl bound lower : 8000 msl bound upper : 11000
Environment
Light	Night
Aircraft 1
Controlling Facilities	tracon : sct.tracon
Operator	common carrier : air carrier
Make Model Name	B757 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	descent : approach
Route In Use	arrival star : kayoh
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
ASRS Report	570567
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	non adherence : published procedure non adherence : clearance
Independent Detector	atc equipment other atc equipment : radar/mode c other controllera
Resolutory Action	controller : issued new clearance
Supplementary
Problem Areas	Flight Crew Human Performance
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Level at 14000 ft at bands intersection, we were cleared the kayoh arrival by socal approach. We started a descent to cross dejay at 8000 ft as published. Passing 11000 ft, the controller asked us what altitude he had cleared us to and said he was surprised that we had descended. I took his clearance of the arrival to mean that we were cleared to descend to make all of the published altitude restrs. He apparently did not.

Original NASA ASRS Text

Title: B757 CREW INBOUND TO SNA IS CLRED ON THE KAYOH ARR AND STARTS DSCNT WITHOUT APPROVAL.

Narrative: LEVEL AT 14000 FT AT BANDS INTXN, WE WERE CLRED THE KAYOH ARR BY SOCAL APCH. WE STARTED A DSCNT TO CROSS DEJAY AT 8000 FT AS PUBLISHED. PASSING 11000 FT, THE CTLR ASKED US WHAT ALT HE HAD CLRED US TO AND SAID HE WAS SURPRISED THAT WE HAD DSNDED. I TOOK HIS CLRNC OF THE ARR TO MEAN THAT WE WERE CLRED TO DSND TO MAKE ALL OF THE PUBLISHED ALT RESTRS. HE APPARENTLY DID NOT.

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.