Narrative:

After receiving clearance for flight from las-mem, the first officer asked the clearance delivery controller to verify the clearance given. The controller had said, at the 2 DME, to turn right to 070, mead 7 departure. After reviewing the mead 7 departure for runway 1, which states, at the 2 DME, to turn right to 070 degrees till passing 4000' MSL, then direct boulder city, the first officer asked the controller why he had issued the heading, when the heading was on the mead 7 departure. The controller then said, after the 2 DME, to turn right to 070 degrees for radar vectors to the mead 7 departure. At this time I should have asked the controller if he wanted us to fly the mead 7 departure as described on the plate. I found out later that the 2 aircraft who departed after us also were confused about the departure clearance and followed the same flight path as we did. On departure, at the 2 DME, I turned right to 070 till passing 4000' MSL. I then turned right to 090 degrees direct boulder city. The tower controller had not told us to contact departure, so we stayed with him. After turning right to boulder city the first officer asked the tower if we should contact departure. At that time he told us to turn left immediately to 050 degrees and then asked us if we weren't told to maintain the 070 degree heading. I told him I had interpreted the clearance to fly the mead 7 as shown and to expect radar vectors while proceeding to boulder city. At this time, the controller stated the that when runway 1 was in use for departures, they could not use the prescribed departure turn to boulder city because of its conflict with runway 25 pattern. At that time I told the controller I was sorry about the confusion of the departure, but that I still did not understand the departure instructions. After our departure Y flight and a Z flight both followed the mead 7 departure as we had and were questioned by the controller about their flight paths. Both crews on these flts also told the controller they had interpreted the clearance to fly the mead 7 as shown. At this time the controller said not to worry, that there was a problem with clearance delivery instructions. He then apologized to us and the other aircraft, and no more was said. My biggest concern was the tone of the controller's voice when we first contracted the controller when he said turn immediately to 050 degrees. I feel we should have questioned clearance delivery or the tower before takeoff about the clearance received. But, I also feel that there was a problem with the issuing of the clearance. Because the 2 departing flts behind us were also confused as they flew the departure the same way I had, this tells me they also perceived the clearance the same way I and my first officer did. I do not know if there was a conflict with another aircraft because of my turn. I feel this was a good learning experience for me to listen to departure clrncs better and be sure to clear up any misunderstanding of clearance instructions. Supplemental information from acn 111731: clearance delivery told us we were 'cleared after departure turn right to 070 degree heading, radar vectors mead 7 departure.' I believe the confusion was the controller telling us to turn right 070 degrees after departure, radar vectors for the mead 7, instead of to expect radar vectors for the mead 7.

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Original NASA ASRS Text

Title: MLG FLT DEPARTING LAS ON MEAD 7 SID. CLRNC WAS AMBIGUOUS. FLT MISUNDERSTOOD CTLR'S INTENT.

Narrative: AFTER RECEIVING CLRNC FOR FLT FROM LAS-MEM, THE F/O ASKED THE CLRNC DELIVERY CTLR TO VERIFY THE CLRNC GIVEN. THE CTLR HAD SAID, AT THE 2 DME, TO TURN RIGHT TO 070, MEAD 7 DEP. AFTER REVIEWING THE MEAD 7 DEP FOR RWY 1, WHICH STATES, AT THE 2 DME, TO TURN RIGHT TO 070 DEGS TILL PASSING 4000' MSL, THEN DIRECT BOULDER CITY, THE F/O ASKED THE CTLR WHY HE HAD ISSUED THE HDG, WHEN THE HDG WAS ON THE MEAD 7 DEP. THE CTLR THEN SAID, AFTER THE 2 DME, TO TURN RIGHT TO 070 DEGS FOR RADAR VECTORS TO THE MEAD 7 DEP. AT THIS TIME I SHOULD HAVE ASKED THE CTLR IF HE WANTED US TO FLY THE MEAD 7 DEP AS DESCRIBED ON THE PLATE. I FOUND OUT LATER THAT THE 2 ACFT WHO DEPARTED AFTER US ALSO WERE CONFUSED ABOUT THE DEP CLRNC AND FOLLOWED THE SAME FLT PATH AS WE DID. ON DEP, AT THE 2 DME, I TURNED RIGHT TO 070 TILL PASSING 4000' MSL. I THEN TURNED RIGHT TO 090 DEGS DIRECT BOULDER CITY. THE TWR CTLR HAD NOT TOLD US TO CONTACT DEP, SO WE STAYED WITH HIM. AFTER TURNING RIGHT TO BOULDER CITY THE F/O ASKED THE TWR IF WE SHOULD CONTACT DEP. AT THAT TIME HE TOLD US TO TURN LEFT IMMEDIATELY TO 050 DEGS AND THEN ASKED US IF WE WEREN'T TOLD TO MAINTAIN THE 070 DEG HDG. I TOLD HIM I HAD INTERPRETED THE CLRNC TO FLY THE MEAD 7 AS SHOWN AND TO EXPECT RADAR VECTORS WHILE PROCEEDING TO BOULDER CITY. AT THIS TIME, THE CTLR STATED THE THAT WHEN RWY 1 WAS IN USE FOR DEPS, THEY COULD NOT USE THE PRESCRIBED DEP TURN TO BOULDER CITY BECAUSE OF ITS CONFLICT WITH RWY 25 PATTERN. AT THAT TIME I TOLD THE CTLR I WAS SORRY ABOUT THE CONFUSION OF THE DEP, BUT THAT I STILL DID NOT UNDERSTAND THE DEP INSTRUCTIONS. AFTER OUR DEP Y FLT AND A Z FLT BOTH FOLLOWED THE MEAD 7 DEP AS WE HAD AND WERE QUESTIONED BY THE CTLR ABOUT THEIR FLT PATHS. BOTH CREWS ON THESE FLTS ALSO TOLD THE CTLR THEY HAD INTERPRETED THE CLRNC TO FLY THE MEAD 7 AS SHOWN. AT THIS TIME THE CTLR SAID NOT TO WORRY, THAT THERE WAS A PROB WITH CLRNC DELIVERY INSTRUCTIONS. HE THEN APOLOGIZED TO US AND THE OTHER ACFT, AND NO MORE WAS SAID. MY BIGGEST CONCERN WAS THE TONE OF THE CTLR'S VOICE WHEN WE FIRST CONTRACTED THE CTLR WHEN HE SAID TURN IMMEDIATELY TO 050 DEGS. I FEEL WE SHOULD HAVE QUESTIONED CLRNC DELIVERY OR THE TWR BEFORE TKOF ABOUT THE CLRNC RECEIVED. BUT, I ALSO FEEL THAT THERE WAS A PROB WITH THE ISSUING OF THE CLRNC. BECAUSE THE 2 DEPARTING FLTS BEHIND US WERE ALSO CONFUSED AS THEY FLEW THE DEP THE SAME WAY I HAD, THIS TELLS ME THEY ALSO PERCEIVED THE CLRNC THE SAME WAY I AND MY F/O DID. I DO NOT KNOW IF THERE WAS A CONFLICT WITH ANOTHER ACFT BECAUSE OF MY TURN. I FEEL THIS WAS A GOOD LEARNING EXPERIENCE FOR ME TO LISTEN TO DEP CLRNCS BETTER AND BE SURE TO CLEAR UP ANY MISUNDERSTANDING OF CLRNC INSTRUCTIONS. SUPPLEMENTAL INFO FROM ACN 111731: CLRNC DELIVERY TOLD US WE WERE 'CLRED AFTER DEP TURN RIGHT TO 070 DEG HDG, RADAR VECTORS MEAD 7 DEP.' I BELIEVE THE CONFUSION WAS THE CTLR TELLING US TO TURN RIGHT 070 DEGS AFTER DEP, RADAR VECTORS FOR THE MEAD 7, INSTEAD OF TO EXPECT RADAR VECTORS FOR THE MEAD 7.

Data retrieved from NASA's ASRS site as of August 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.