Flight crew misinterpret clearance 'descend and maintain 17000 ft, cleared for vucan STAR' at cyyc t...

Attributes
ACN	611315
Time
Date	200403
Day	Tue
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : cyyc.airport
State Reference	AB
Altitude	msl bound lower : 16500 msl bound upper : 17000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : czeg.artcc
Operator	common carrier : air carrier
Make Model Name	B727-200
Operating Under FAR Part	Part 121
Flight Phase	descent : intermediate altitude descent : approach
Route In Use	arrival star : vucan
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 140 flight time total : 7500 flight time type : 2000
ASRS Report	611315
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : multi engine pilot : cfi pilot : atp
Experience	flight time last 90 days : 150 flight time total : 10050 flight time type : 400
ASRS Report	611754
Events
Anomaly	altitude deviation : overshoot conflict : airborne less severe non adherence : clearance
Independent Detector	other controllera
Resolutory Action	controller : issued alert flight crew : returned to assigned altitude
Miss Distance	horizontal : 10000 vertical : 1500
Supplementary
Problem Areas	Flight Crew Human Performance Chart Or Publication Airspace Structure ATC Human Performance ATC Facility
Primary Problem	Ambiguous
Situations
Chart	star : vucan star

Narrative:

We were flying from msp to cyyc. At about 60 mi from cyyc, edmonton center told us to descend and maintain 17000 ft and we were cleared for the vucan 7 arrival into cyyc. We were at 31000 ft. We started our descent. The vucan 7 arrival has a crossing restr to cross 'third' (intersection) at 12000 ft. It does not say expect to cross, it is a published crossing restr. I have flown this arrival before and in the past have continued the descent to make this crossing restr once we were 'cleared' for the arrival. In fact the first few times I flew this arrival I queried ATC if they wanted us to cross 'third' at 12000 ft and ATC came back with yes you have been cleared for the arrival. This time as we were passing through 17000 ft I informed ATC we were continuing down to 12000 ft. ATC called back and said to maintain 17000 ft. We immediately arrested our descent but went about 500-600 ft below 17000 ft. We then immediately climbed back up to 17000 ft. ATC told us we were supposed to maintain 17000 ft. I told them we had been cleared for the arrival. They didn't contradict this but said we were supposed to maintain 17000 ft. It seems to me that we were given a contradictory clearance. If we were cleared for the arrival then we were cleared to make the crossing restr. In the future we will clarify what we should do but I also feel that the arrival plate should say 'expect to cross' or the controller should not clear you for the arrival till they want you to make the restr. Callback conversation with reporter revealed the following information: the reporter advised he spoke with the chief pilot of his air carrier subsequent to this event and came away with no clrer picture of what is required for STAR operations in canada. He stated he felt the only certain course of action to insure compliance with ATC expectations is to inquire specifically when given a clearance for a STAR.

Original NASA ASRS Text

Title: FLT CREW MISINTERPRET CLRNC 'DSND AND MAINTAIN 17000 FT, CLRED FOR VUCAN STAR' AT CYYC TO ALLOW DSCNT TO THIRD INTXN AT OR BELOW 12000 FT. AS THEY DEPART 17000 FT ARTCC ALERTS THEM TO MAINTAIN 17000 FT AS ASSIGNED DUE TO TFC AT 16000 FT.

Narrative: WE WERE FLYING FROM MSP TO CYYC. AT ABOUT 60 MI FROM CYYC, EDMONTON CTR TOLD US TO DSND AND MAINTAIN 17000 FT AND WE WERE CLRED FOR THE VUCAN 7 ARR INTO CYYC. WE WERE AT 31000 FT. WE STARTED OUR DSCNT. THE VUCAN 7 ARR HAS A XING RESTR TO CROSS 'THIRD' (INTXN) AT 12000 FT. IT DOES NOT SAY EXPECT TO CROSS, IT IS A PUBLISHED XING RESTR. I HAVE FLOWN THIS ARR BEFORE AND IN THE PAST HAVE CONTINUED THE DSCNT TO MAKE THIS XING RESTR ONCE WE WERE 'CLRED' FOR THE ARR. IN FACT THE FIRST FEW TIMES I FLEW THIS ARR I QUERIED ATC IF THEY WANTED US TO CROSS 'THIRD' AT 12000 FT AND ATC CAME BACK WITH YES YOU HAVE BEEN CLRED FOR THE ARR. THIS TIME AS WE WERE PASSING THROUGH 17000 FT I INFORMED ATC WE WERE CONTINUING DOWN TO 12000 FT. ATC CALLED BACK AND SAID TO MAINTAIN 17000 FT. WE IMMEDIATELY ARRESTED OUR DSCNT BUT WENT ABOUT 500-600 FT BELOW 17000 FT. WE THEN IMMEDIATELY CLBED BACK UP TO 17000 FT. ATC TOLD US WE WERE SUPPOSED TO MAINTAIN 17000 FT. I TOLD THEM WE HAD BEEN CLRED FOR THE ARR. THEY DIDN'T CONTRADICT THIS BUT SAID WE WERE SUPPOSED TO MAINTAIN 17000 FT. IT SEEMS TO ME THAT WE WERE GIVEN A CONTRADICTORY CLRNC. IF WE WERE CLRED FOR THE ARR THEN WE WERE CLRED TO MAKE THE XING RESTR. IN THE FUTURE WE WILL CLARIFY WHAT WE SHOULD DO BUT I ALSO FEEL THAT THE ARR PLATE SHOULD SAY 'EXPECT TO CROSS' OR THE CTLR SHOULD NOT CLR YOU FOR THE ARR TILL THEY WANT YOU TO MAKE THE RESTR. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR ADVISED HE SPOKE WITH THE CHIEF PLT OF HIS ACR SUBSEQUENT TO THIS EVENT AND CAME AWAY WITH NO CLRER PICTURE OF WHAT IS REQUIRED FOR STAR OPS IN CANADA. HE STATED HE FELT THE ONLY CERTAIN COURSE OF ACTION TO INSURE COMPLIANCE WITH ATC EXPECTATIONS IS TO INQUIRE SPECIFICALLY WHEN GIVEN A CLRNC FOR A STAR.

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.

Flight crew misinterpret clearance 'descend and maintain 17000 ft, cleared for vucan STAR' at cyyc to allow descent to third intersection at or below 12000 ft. As they depart 17000 ft ARTCC alerts them to maintain 17000 ft as assigned due to traffic at 16000 ft.