Medium large transport on STAR anticipates crossing restriction and descends without clearance.

Attributes
ACN	118434
Time
Date	198907
Day	Sat
Local Time Of Day	1801 To 2400
Place
Locale Reference	atc facility : btg
State Reference	WA
Altitude	msl bound lower : 15700 msl bound upper : 16000
Environment
Flight Conditions	VMC
Light	Night
Aircraft 1
Controlling Facilities	artcc : zse
Operator	common carrier : air carrier
Make Model Name	Medium Large Transport, Low Wing, 2 Turbojet Eng
Navigation In Use	Other Other
Flight Phase	cruise other descent other
Route In Use	arrival star : star
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : instrument pilot : commercial
Experience	flight time last 90 days : 125 flight time total : 10645 flight time type : 3525
ASRS Report	118434
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : clearance
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

We were en route from eug to pdx cruising at 16,000'. On the moxee 2 arrival at pdx, the first officer pointed out that there was a crossing restriction at flowr (10,000' at 250 KTS). I calculated the descent point at 60 DME. The first officer went off center frequency to copy the ATIS. When I reached the 60 DME point I started the descent, reporting to sea center that I was leaving 16,000'. At this point the altitude alert sounded and sea center asked what altitude we were cleared to and cleared us to 10,000'. At this time I realized that I had not been given descent clearance when I started the descent. This was a mental lapse on my part. I was so intent on making the crossing restriction (which had never been issued) that I overlooked the basics.

Original NASA ASRS Text

Title: MLG ON STAR ANTICIPATES CROSSING RESTRICTION AND DESCENDS WITHOUT CLRNC.

Narrative: WE WERE ENRTE FROM EUG TO PDX CRUISING AT 16,000'. ON THE MOXEE 2 ARR AT PDX, THE F/O POINTED OUT THAT THERE WAS A XING RESTRICTION AT FLOWR (10,000' AT 250 KTS). I CALCULATED THE DSCNT POINT AT 60 DME. THE F/O WENT OFF CENTER FREQ TO COPY THE ATIS. WHEN I REACHED THE 60 DME POINT I STARTED THE DSCNT, REPORTING TO SEA CENTER THAT I WAS LEAVING 16,000'. AT THIS POINT THE ALT ALERT SOUNDED AND SEA CENTER ASKED WHAT ALT WE WERE CLRED TO AND CLRED US TO 10,000'. AT THIS TIME I REALIZED THAT I HAD NOT BEEN GIVEN DSCNT CLRNC WHEN I STARTED THE DSCNT. THIS WAS A MENTAL LAPSE ON MY PART. I WAS SO INTENT ON MAKING THE XING RESTRICTION (WHICH HAD NEVER BEEN ISSUED) THAT I OVERLOOKED THE BASICS.

Data retrieved from NASA's ASRS site as of August 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.