Narrative:

Departing out of las vegas, nv, on the shead 2 departure, we were given the clearance to cross tarrk at 11000 ft and climb to FL190. I set 19000 ft in the altitude alerter and advised the captain of the departure clearance. We both incorrectly assumed that we were to cross tarrk at 11000 ft or above for terrain clearance not aircraft separation since the clearance was to FL190. We had climbed to 11800 ft before departure control requested an immediate descent to 11000 ft, then asked us to report level at 11000 ft. Shortly after that, we were given a phone number to call. 1) on the departure brief, we reviewed the expanded section for our departure runway for correct route. There is no mention of altitude in the route description. Add altitude to route descriptions. 2) if the controller wanted us to level at 11000 ft for aircraft separation, why did he clear us to FL190? Why didn't he just have us level at 11000 ft? Then issue further climb after passing inbound traffic. 3) the departure procedure should be changed to more accurately reflect mandatory altitudes and to specify these altitudes, not only assure terrain clearance, but aircraft separation as well. Supplemental information from acn 609569: in my mind I was thinking he wanted a minimum of 11000 ft by the time we were at tarrk and cleared on up to FL190. My error.

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Original NASA ASRS Text

Title: FRACTIONAL TURBOJET FLT CREW OVERSHOOT L30 ASSIGNED ALT EXECUTING THE LAS TARRK SID, CONFLICTING WITH OVERHEAD ARR TFC. CREW ASSUMED DIFFERENT CLRNC INSTRUCTION.

Narrative: DEPARTING OUT OF LAS VEGAS, NV, ON THE SHEAD 2 DEP, WE WERE GIVEN THE CLRNC TO CROSS TARRK AT 11000 FT AND CLB TO FL190. I SET 19000 FT IN THE ALT ALERTER AND ADVISED THE CAPT OF THE DEP CLRNC. WE BOTH INCORRECTLY ASSUMED THAT WE WERE TO CROSS TARRK AT 11000 FT OR ABOVE FOR TERRAIN CLRNC NOT ACFT SEPARATION SINCE THE CLRNC WAS TO FL190. WE HAD CLBED TO 11800 FT BEFORE DEP CTL REQUESTED AN IMMEDIATE DSCNT TO 11000 FT, THEN ASKED US TO RPT LEVEL AT 11000 FT. SHORTLY AFTER THAT, WE WERE GIVEN A PHONE NUMBER TO CALL. 1) ON THE DEP BRIEF, WE REVIEWED THE EXPANDED SECTION FOR OUR DEP RWY FOR CORRECT RTE. THERE IS NO MENTION OF ALT IN THE RTE DESCRIPTION. ADD ALT TO RTE DESCRIPTIONS. 2) IF THE CTLR WANTED US TO LEVEL AT 11000 FT FOR ACFT SEPARATION, WHY DID HE CLR US TO FL190? WHY DIDN'T HE JUST HAVE US LEVEL AT 11000 FT? THEN ISSUE FURTHER CLB AFTER PASSING INBOUND TFC. 3) THE DEP PROC SHOULD BE CHANGED TO MORE ACCURATELY REFLECT MANDATORY ALTS AND TO SPECIFY THESE ALTS, NOT ONLY ASSURE TERRAIN CLRNC, BUT ACFT SEPARATION AS WELL. SUPPLEMENTAL INFO FROM ACN 609569: IN MY MIND I WAS THINKING HE WANTED A MINIMUM OF 11000 FT BY THE TIME WE WERE AT TARRK AND CLRED ON UP TO FL190. MY ERROR.

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.