B737-300 flight crew descended below cleared altitude while flying ksino RNAV 1 arrival to las.

Attributes
ACN	568579
Time
Date	200212
Day	Thu
Local Time Of Day	0601 To 1200
Place
Locale Reference	intersection : miraj
State Reference	NV
Altitude	msl bound lower : 10800 msl bound upper : 12000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	tracon : l30.tracon
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Navigation In Use	other
Flight Phase	descent : intermediate altitude
Route In Use	arrival star : ksino 1
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 225 flight time total : 9000 flight time type : 6000
ASRS Report	568579
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : atp
Experience	flight time last 90 days : 176 flight time total : 6900 flight time type : 567
ASRS Report	568581
Events
Anomaly	altitude deviation : excursion from assigned altitude non adherence : company policies non adherence : published procedure non adherence : far non adherence : clearance other anomaly other
Independent Detector	atc equipment other atc equipment : radar other controllera
Resolutory Action	controller : issued new clearance controller : issued advisory
Consequence	other
Supplementary
Problem Areas	Flight Crew Human Performance Chart Or Publication Company Aircraft
Primary Problem	Flight Crew Human Performance
Air Traffic Incident	Pilot Deviation

Narrative:

Altitude deviation. First officer flying ksino 1 arrival into las. Initially cleared 'direct ksino for the ksino 1 arrival.' later we were given 'direct luxor, ksino 1 arrival, cross luxor at and maintain 12000 ft, 250 KIAS.' I acknowledged, then went off frequency to get ATIS, and again a few mins later to get our gate. While I was getting the gate from las operations, first officer crossed luxor at 12000 ft, 250 KIAS, and dialed in 10000 ft in the altitude window for miraj and began the descent. I came back on frequency and asked the first officer 'cleared to 10?' his answer was, 'yes, cross miraj at 10.' 1 min later, las approach asked us to 'say altitude.' I answered, '10800 ft for miraj at 10.' her response was 'you were not cleared to descend via the ksino 1 arrival.' I told her I was sorry, that we misunderstood and asked her what she would like us to do now. She gave us a vector and a descent to 8500 ft and we continued our arrival into las. Discussion with my first officer revealed that he erroneously thought clearance for the arrival included clearance for all mandatory altitudes as well on RNAV approachs. Numerous NOTAMS and company notices back and forth on the vegas RNAV stuff added to his confusion. I instructed my first officer that for any arrival, RNAV or otherwise, that clearance for the arrival does not include clearance to descend unless given the magic words 'descend via the....' I then showed him airway manual and ATC reference. My first officer is still fairly new. Lesson learned: for me, next time I come back on frequency, I will verify a new altitude by asking, 'understand we were told to descend via....?' we live and learn. Supplemental information from acn 568581: subsequently, the captain and I discussed the situation, reviewed RNAV procedures, discussed our original clearance, reviewed the applicable commercial chart section on ATC procedures and the requirement to receive the exact phraseology of 'cleared to descend via the xxxxx arrival.' we also discussed crew coordination and the constant requirement to 'trust but verify' with regard to altitude assignments and clrncs. Being inexperienced with RNAV arrs was a factor but not the main one.

Original NASA ASRS Text

Title: B737-300 FLC DSNDED BELOW CLRED ALT WHILE FLYING KSINO RNAV 1 ARR TO LAS.

Narrative: ALTDEV. FO FLYING KSINO 1 ARR INTO LAS. INITIALLY CLRED 'DIRECT KSINO FOR THE KSINO 1 ARR.' LATER WE WERE GIVEN 'DIRECT LUXOR, KSINO 1 ARR, CROSS LUXOR AT AND MAINTAIN 12000 FT, 250 KIAS.' I ACKNOWLEDGED, THEN WENT OFF FREQ TO GET ATIS, AND AGAIN A FEW MINS LATER TO GET OUR GATE. WHILE I WAS GETTING THE GATE FROM LAS OPS, FO CROSSED LUXOR AT 12000 FT, 250 KIAS, AND DIALED IN 10000 FT IN THE ALT WINDOW FOR MIRAJ AND BEGAN THE DSCNT. I CAME BACK ON FREQ AND ASKED THE FO 'CLRED TO 10?' HIS ANSWER WAS, 'YES, CROSS MIRAJ AT 10.' 1 MIN LATER, LAS APCH ASKED US TO 'SAY ALT.' I ANSWERED, '10800 FT FOR MIRAJ AT 10.' HER RESPONSE WAS 'YOU WERE NOT CLRED TO DSND VIA THE KSINO 1 ARR.' I TOLD HER I WAS SORRY, THAT WE MISUNDERSTOOD AND ASKED HER WHAT SHE WOULD LIKE US TO DO NOW. SHE GAVE US A VECTOR AND A DSCNT TO 8500 FT AND WE CONTINUED OUR ARR INTO LAS. DISCUSSION WITH MY FO REVEALED THAT HE ERRONEOUSLY THOUGHT CLRNC FOR THE ARR INCLUDED CLRNC FOR ALL MANDATORY ALTS AS WELL ON RNAV APCHS. NUMEROUS NOTAMS AND COMPANY NOTICES BACK AND FORTH ON THE VEGAS RNAV STUFF ADDED TO HIS CONFUSION. I INSTRUCTED MY FO THAT FOR ANY ARR, RNAV OR OTHERWISE, THAT CLRNC FOR THE ARR DOES NOT INCLUDE CLRNC TO DSND UNLESS GIVEN THE MAGIC WORDS 'DSND VIA THE....' I THEN SHOWED HIM AIRWAY MANUAL AND ATC REF. MY FO IS STILL FAIRLY NEW. LESSON LEARNED: FOR ME, NEXT TIME I COME BACK ON FREQ, I WILL VERIFY A NEW ALT BY ASKING, 'UNDERSTAND WE WERE TOLD TO DSND VIA....?' WE LIVE AND LEARN. SUPPLEMENTAL INFO FROM ACN 568581: SUBSEQUENTLY, THE CAPT AND I DISCUSSED THE SIT, REVIEWED RNAV PROCS, DISCUSSED OUR ORIGINAL CLRNC, REVIEWED THE APPLICABLE COMMERCIAL CHART SECTION ON ATC PROCS AND THE REQUIREMENT TO RECEIVE THE EXACT PHRASEOLOGY OF 'CLRED TO DSND VIA THE XXXXX ARR.' WE ALSO DISCUSSED CREW COORD AND THE CONSTANT REQUIREMENT TO 'TRUST BUT VERIFY' WITH REGARD TO ALT ASSIGNMENTS AND CLRNCS. BEING INEXPERIENCED WITH RNAV ARRS WAS A FACTOR BUT NOT THE MAIN ONE.

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.