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B717-200 flight crew question ZLA controller's clearance direct to pgs VORTAC, then via las tyssn RNAV arrival, if the clearance was also a clearance to 'descend via,' which it was not.
| Attributes | |
| ACN | 614017 |
| Time | |
| Date | 200404 |
| Day | Mon |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | atc facility : zla.artcc |
| State Reference | CA |
| Altitude | msl single value : 31000 |
| Environment | |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zla.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | B717 (Formerly MD-95) |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level descent : vacating altitude descent : approach |
| Route In Use | arrival : on vectors arrival star : tyssn |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 210 flight time total : 6500 flight time type : 2500 |
| ASRS Report | 614017 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Events | |
| Anomaly | non adherence : published procedure other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | flight crew : became reoriented other |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Problem Areas | ATC Human Performance Chart Or Publication FAA Flight Crew Human Performance |
| Primary Problem | Flight Crew Human Performance |
Narrative:
This was my first time flying to las, and we were cleared to pgs, with the pgs 1 arrival. When we checked in with ZLA, we were cleared direct to pgs, then 'via' the tyssn RNAV 1 arrival (tyssn TYSSN1). The tyssn arrival is an FMS arrival, with mandatory speeds and altitudes, all of which are preloaded into the FMS. The arrival is much like the korry or dylan arrs at lga and ewr respectively, in that once cleared for the arrival, you set the bottom altitude, and the FMS will fly a profile descent. However, on both the korry and dylan FMS arrs, there is a large note that you must maintain your last assigned altitude until 'cleared to descend via the arrival.' our clearance was 'cleared via the arrival' in las. We clarified with center that they wanted us to maintain FL310, and fly the arrival, which is what center wanted. The center controller advised us that this is a common question, and that the next controller would clear us to 'descend via the arrival.' if the tyssn arrival had the same note of warning regarding the necessity to maintain your last altitude until specifically cleared to 'descend via the arrival,' I feel this would be clrer. Also, the controller phraseology should include a 'maintain FL310, cleared pgs and the tyssn arrival.' that would eliminate my confusion.
Original NASA ASRS Text
Title: B717-200 FLT CREW QUESTION ZLA CTLR'S CLRNC DIRECT TO PGS VORTAC, THEN VIA LAS TYSSN RNAV ARR, IF THE CLRNC WAS ALSO A CLRNC TO 'DSND VIA,' WHICH IT WAS NOT.
Narrative: THIS WAS MY FIRST TIME FLYING TO LAS, AND WE WERE CLRED TO PGS, WITH THE PGS 1 ARR. WHEN WE CHKED IN WITH ZLA, WE WERE CLRED DIRECT TO PGS, THEN 'VIA' THE TYSSN RNAV 1 ARR (TYSSN TYSSN1). THE TYSSN ARR IS AN FMS ARR, WITH MANDATORY SPDS AND ALTS, ALL OF WHICH ARE PRELOADED INTO THE FMS. THE ARR IS MUCH LIKE THE KORRY OR DYLAN ARRS AT LGA AND EWR RESPECTIVELY, IN THAT ONCE CLRED FOR THE ARR, YOU SET THE BOTTOM ALT, AND THE FMS WILL FLY A PROFILE DSCNT. HOWEVER, ON BOTH THE KORRY AND DYLAN FMS ARRS, THERE IS A LARGE NOTE THAT YOU MUST MAINTAIN YOUR LAST ASSIGNED ALT UNTIL 'CLRED TO DSND VIA THE ARR.' OUR CLRNC WAS 'CLRED VIA THE ARR' IN LAS. WE CLARIFIED WITH CTR THAT THEY WANTED US TO MAINTAIN FL310, AND FLY THE ARR, WHICH IS WHAT CTR WANTED. THE CTR CTLR ADVISED US THAT THIS IS A COMMON QUESTION, AND THAT THE NEXT CTLR WOULD CLR US TO 'DSND VIA THE ARR.' IF THE TYSSN ARR HAD THE SAME NOTE OF WARNING REGARDING THE NECESSITY TO MAINTAIN YOUR LAST ALT UNTIL SPECIFICALLY CLRED TO 'DSND VIA THE ARR,' I FEEL THIS WOULD BE CLRER. ALSO, THE CTLR PHRASEOLOGY SHOULD INCLUDE A 'MAINTAIN FL310, CLRED PGS AND THE TYSSN ARR.' THAT WOULD ELIMINATE MY CONFUSION.
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.