Flight crew started descent on a STAR arrival before ATC had cleared them for descent.

Attributes
ACN	296417
Time
Date	199502
Day	Sun
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : jfk airport : bos
State Reference	NY
Altitude	msl bound lower : 22000 msl bound upper : 23000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zbw tracon : bna
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other Other
Flight Phase	cruise other descent other
Route In Use	arrival other arrival star : star
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 200 flight time total : 8000 flight time type : 4000
ASRS Report	296417
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other
Independent Detector	atc equipment other atc equipment : unspecified 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	Pilot Deviation

Narrative:

Inbound to bos on orwz (STAR), had programmed FMC for expected clearance 250 KTS 11000 ft at pvd. FMC presentation indicated aircraft was at top of descent. I mistakenly began descent prior to receipt of ATC clearance. At approximately FL220, ATC cleared us to 14000 ft and asked if we had already begun the descent. I suddenly realized my error and reset the mode control panel for leveloff at 14000 ft. Apparently no conflict with other traffic was created by this error. However, a valuable lesson was relearned. Contributing factors: 1) PNF was on the other radio checking ATIS. 2) end of 11 hour (actual) international trip. 3) clearance for STAR is different from profile descent. The latter includes clearance for altitude changes where the former does not.

Original NASA ASRS Text

Title: FLC STARTED DSCNT ON A STAR ARR BEFORE ATC HAD CLRED THEM FOR DSCNT.

Narrative: INBOUND TO BOS ON ORWZ (STAR), HAD PROGRAMMED FMC FOR EXPECTED CLRNC 250 KTS 11000 FT AT PVD. FMC PRESENTATION INDICATED ACFT WAS AT TOP OF DSCNT. I MISTAKENLY BEGAN DSCNT PRIOR TO RECEIPT OF ATC CLRNC. AT APPROX FL220, ATC CLRED US TO 14000 FT AND ASKED IF WE HAD ALREADY BEGUN THE DSCNT. I SUDDENLY REALIZED MY ERROR AND RESET THE MODE CTL PANEL FOR LEVELOFF AT 14000 FT. APPARENTLY NO CONFLICT WITH OTHER TFC WAS CREATED BY THIS ERROR. HOWEVER, A VALUABLE LESSON WAS RELEARNED. CONTRIBUTING FACTORS: 1) PNF WAS ON THE OTHER RADIO CHKING ATIS. 2) END OF 11 HR (ACTUAL) INTL TRIP. 3) CLRNC FOR STAR IS DIFFERENT FROM PROFILE DSCNT. THE LATTER INCLUDES CLRNC FOR ALT CHANGES WHERE THE FORMER DOES 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.