Cftt as PIC has clearance interpretation problem.

Attributes
ACN	187517
Time
Date	199108
Day	Thu
Local Time Of Day	1201 To 1800
Place
Locale Reference	atc facility : ffu airport : slc
State Reference	UT
Altitude	msl bound lower : 12500 msl bound upper : 17000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Large Transport, Low Wing, 3 Turbojet Eng
Flight Phase	descent other
Route In Use	enroute : direct enroute airway : zlc
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 150 flight time total : 10000 flight time type : 6000
ASRS Report	187517
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Events
Anomaly	altitude deviation : overshoot altitude deviation : crossing restriction not met non adherence : clearance other spatial deviation
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance flight crew : returned to intended course or assigned course other
Consequence	Other
Supplementary
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation
Situations
ATC Facility	procedure or policy : unspecified

Narrative:

While in cruise at FL280, given a clearance to descend to cross 10 east of ffu at 11000 ft on airway between grand junction, co, and fairview (ffu), copilot was out of cockpit in the john at the time and descent was started since it was a fairly tight crossing restr. After his return he was briefed that we had a crossing restr and were descending. Passing through 13000 ft to 12500 ft we were asked what altitude we were going to since we had only been cleared to 17000 ft. We were told that the minimum safe altitude was 13000 ft and to climb to 15000 ft. We climbed from 12500 ft to 15000 ft and proceeded to slc to land uneventfully. Part of this problem was that upon initial receipt of clearance it seemed to be a low altitude to go to but the crossing restr seemed more important than the altitude we were cleared to reach. In the future I know that I'll pay more attention to 'nagging' questions of altitude for a particular area and be more aware of terrain. Cavu conditions told me that we would not hit anything but it was still an eye opener.

Original NASA ASRS Text

Title: CFTT AS PIC HAS CLRNC INTERP PROBLEM.

Narrative: WHILE IN CRUISE AT FL280, GIVEN A CLRNC TO DSND TO CROSS 10 E OF FFU AT 11000 FT ON AIRWAY BTWN GRAND JUNCTION, CO, AND FAIRVIEW (FFU), COPLT WAS OUT OF COCKPIT IN THE JOHN AT THE TIME AND DSCNT WAS STARTED SINCE IT WAS A FAIRLY TIGHT XING RESTR. AFTER HIS RETURN HE WAS BRIEFED THAT WE HAD A XING RESTR AND WERE DSNDING. PASSING THROUGH 13000 FT TO 12500 FT WE WERE ASKED WHAT ALT WE WERE GOING TO SINCE WE HAD ONLY BEEN CLRED TO 17000 FT. WE WERE TOLD THAT THE MINIMUM SAFE ALT WAS 13000 FT AND TO CLB TO 15000 FT. WE CLBED FROM 12500 FT TO 15000 FT AND PROCEEDED TO SLC TO LAND UNEVENTFULLY. PART OF THIS PROB WAS THAT UPON INITIAL RECEIPT OF CLRNC IT SEEMED TO BE A LOW ALT TO GO TO BUT THE XING RESTR SEEMED MORE IMPORTANT THAN THE ALT WE WERE CLRED TO REACH. IN THE FUTURE I KNOW THAT I'LL PAY MORE ATTN TO 'NAGGING' QUESTIONS OF ALT FOR A PARTICULAR AREA AND BE MORE AWARE OF TERRAIN. CAVU CONDITIONS TOLD ME THAT WE WOULD NOT HIT ANYTHING BUT IT WAS STILL AN EYE OPENER.

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.