Flight crew of HS125 descends on dbl transition to ILS runway 26 at ril without clearance.

Attributes
ACN	681277
Time
Date	200512
Local Time Of Day	1201 To 1800
Place
Locale Reference	navaid : dbl.vor
State Reference	CO
Altitude	msl single value : 17000
Environment
Flight Conditions	IMC
Weather Elements	Snow Ice
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : ase.tracon
Operator	general aviation : corporate
Make Model Name	BAe 125 Series 800
Operating Under FAR Part	Part 91
Navigation In Use	other
Flight Phase	descent : approach
Flight Plan	IFR
Person 1
Affiliation	company : corporate
Function	flight crew : captain oversight : pic
Qualification	pilot : multi engine pilot : atp
Experience	flight time last 90 days : 200 flight time total : 5000 flight time type : 3000
ASRS Report	681277
Person 2
Affiliation	company : corporate
Function	flight crew : first officer
Events
Anomaly	altitude deviation : excursion from assigned altitude inflight encounter : weather inflight encounter other non adherence : clearance non adherence : published procedure
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance controller : issued alert
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	Chart Or Publication Flight Crew Human Performance ATC Human Performance
Primary Problem	Ambiguous
Air Traffic Incident	Pilot Deviation

Narrative:

5 NM southeast of dbl (red table) VOR at 17000 ft in IMC conditions with moderate icing and with the ase (aspen) airport below minimums; we advised ase TRACON that instead of holding over dbl we intend to conduct the ILS runway 26 into ril (rifle) and are requesting the dbl transition to the approach. Upon receiving TRACON clearance as 'cleared via the dbl transition to the ILS runway 26 course' and 'expect final approach clearance shortly' while over the dbl VOR; we joined the route and began a descent to comply with the step downs of the transition. Upon passing through 16000 ft; the ase TRACON controller advised us to stop the descent at 16000 ft. We inquired as to the previously issued clearance and he stated that it was a confusing clearance and he should have stated the altitude portion of the clearance. We were cleared via the transition; but we were awaiting the altitude clearance...followed immediately by a 'cleared the ILS runway 26 at ril cross socky intersection at or above 13100 ft -- switch to advisories is approved.' we continued the approach; and completed an otherwise uneventful flight. I contacted the ase TRACON controller to see what the situation that had transpired really was all about. He reiterated that this was a confusing clearance because of a technicality that only a 'local' would know. It appears that the airspace north and northwest of dbl (red table) VOR belongs to ase TRACON 'only if landing ase' however; the moment that we stated we were diverting to rifle the airspace belongs to den ARTCC as in shown by the frequency on the approach plate. Although ase TRACON was working us in; the airspace below 17000 ft was not his to offer and therefore required him to contact den ARTCC via land line to get the approval. As a result of us attempting to comply with the transition and initial approach segment crossing restrs he got an '#@* chewing' from den ARTCC which in turn trickled down to us. In the future ase TRACON should always state 'maintain XXX ft and cleared via the dbl transition to the ILS runway 26 course' and then state 'expect final approach clearance shortly.'

Original NASA ASRS Text

Title: FLT CREW OF HS125 DESCENDS ON DBL TRANSITION TO ILS RWY 26 AT RIL WITHOUT CLRNC.

Narrative: 5 NM SE OF DBL (RED TABLE) VOR AT 17000 FT IN IMC CONDITIONS WITH MODERATE ICING AND WITH THE ASE (ASPEN) ARPT BELOW MINIMUMS; WE ADVISED ASE TRACON THAT INSTEAD OF HOLDING OVER DBL WE INTEND TO CONDUCT THE ILS RWY 26 INTO RIL (RIFLE) AND ARE REQUESTING THE DBL TRANSITION TO THE APCH. UPON RECEIVING TRACON CLRNC AS 'CLRED VIA THE DBL TRANSITION TO THE ILS RWY 26 COURSE' AND 'EXPECT FINAL APCH CLRNC SHORTLY' WHILE OVER THE DBL VOR; WE JOINED THE RTE AND BEGAN A DSCNT TO COMPLY WITH THE STEP DOWNS OF THE TRANSITION. UPON PASSING THROUGH 16000 FT; THE ASE TRACON CTLR ADVISED US TO STOP THE DSCNT AT 16000 FT. WE INQUIRED AS TO THE PREVIOUSLY ISSUED CLRNC AND HE STATED THAT IT WAS A CONFUSING CLRNC AND HE SHOULD HAVE STATED THE ALTITUDE PORTION OF THE CLRNC. WE WERE CLRED VIA THE TRANSITION; BUT WE WERE AWAITING THE ALTITUDE CLRNC...FOLLOWED IMMEDIATELY BY A 'CLRED THE ILS RWY 26 AT RIL CROSS SOCKY INTXN AT OR ABOVE 13100 FT -- SWITCH TO ADVISORIES IS APPROVED.' WE CONTINUED THE APCH; AND COMPLETED AN OTHERWISE UNEVENTFUL FLT. I CONTACTED THE ASE TRACON CTLR TO SEE WHAT THE SITUATION THAT HAD TRANSPIRED REALLY WAS ALL ABOUT. HE REITERATED THAT THIS WAS A CONFUSING CLRNC BECAUSE OF A TECHNICALITY THAT ONLY A 'LOCAL' WOULD KNOW. IT APPEARS THAT THE AIRSPACE N AND NW OF DBL (RED TABLE) VOR BELONGS TO ASE TRACON 'ONLY IF LNDG ASE' HOWEVER; THE MOMENT THAT WE STATED WE WERE DIVERTING TO RIFLE THE AIRSPACE BELONGS TO DEN ARTCC AS IN SHOWN BY THE FREQUENCY ON THE APCH PLATE. ALTHOUGH ASE TRACON WAS WORKING US IN; THE AIRSPACE BELOW 17000 FT WAS NOT HIS TO OFFER AND THEREFORE REQUIRED HIM TO CONTACT DEN ARTCC VIA LAND LINE TO GET THE APPROVAL. AS A RESULT OF US ATTEMPTING TO COMPLY WITH THE TRANSITION AND INITIAL APCH SEGMENT CROSSING RESTRS HE GOT AN '#@* CHEWING' FROM DEN ARTCC WHICH IN TURN TRICKLED DOWN TO US. IN THE FUTURE ASE TRACON SHOULD ALWAYS STATE 'MAINTAIN XXX FT AND CLRED VIA THE DBL TRANSITION TO THE ILS RWY 26 COURSE' AND THEN STATE 'EXPECT FINAL APCH CLRNC SHORTLY.'

Data retrieved from NASA's ASRS site as of January 2009 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.