Narrative:

Cleared for takeoff on runway 27; vally one RNAV departure. No heading assigned. In absence of assigned heading we followed the RNAV SID and turned toward metts. Upon checking in with departure he told us to turn back to heading 300 degrees. Controller said on this departure we are only supposed to fly headings assigned. I know it says that on the ATIS; but in the absence of an assigned heading; you are supposed to fly the last assigned -- which in this case is the RNAV SID. Seems like mia has a screwy departure situation set up. If they want you to fly headings on departure; they should probably put that on your clearance; or in the SID. That way if tower doesn't give you a heading to fly on takeoff; you still have a plan.

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Original NASA ASRS Text

Title: CLRD VIA THE VALLY RNAV SID OFF MIA; B737 FLIES SID VICE HEADING WHEN NONE IS ASSIGNED AS DIRECTED BY ATIS.

Narrative: CLRED FOR TKOF ON RWY 27; VALLY ONE RNAV DEP. NO HDG ASSIGNED. IN ABSENCE OF ASSIGNED HDG WE FOLLOWED THE RNAV SID AND TURNED TOWARD METTS. UPON CHKING IN WITH DEP HE TOLD US TO TURN BACK TO HDG 300 DEGS. CTLR SAID ON THIS DEP WE ARE ONLY SUPPOSED TO FLY HDGS ASSIGNED. I KNOW IT SAYS THAT ON THE ATIS; BUT IN THE ABSENCE OF AN ASSIGNED HDG; YOU ARE SUPPOSED TO FLY THE LAST ASSIGNED -- WHICH IN THIS CASE IS THE RNAV SID. SEEMS LIKE MIA HAS A SCREWY DEP SITUATION SET UP. IF THEY WANT YOU TO FLY HDGS ON DEP; THEY SHOULD PROBABLY PUT THAT ON YOUR CLRNC; OR IN THE SID. THAT WAY IF TWR DOESN'T GIVE YOU A HDG TO FLY ON TKOF; YOU STILL HAVE A PLAN.

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