Narrative:

Instructed to taxi into position and hold runway 12R and 'be ready.' after taxiing into position, advanced thrust levers to 1.2 EPR (DC9 high idle) to aid in anticipated expeditious acceleration. Upon hearing 'air carrier XXX cleared for takeoff,' rapidly advanced thrust to takeoff position. I believed that first officer acknowledged heading to be 250 degrees. After takeoff, climbing through 400 ft, started turn, switched to departure control, first officer questioned heading with departure and we were instructed to come to heading 230 degrees. After arrival in iah, I was asked to call stl tower chief. Our discussion revealed that the assigned departure heading was actually 125 degrees and no traffic was on final requiring an 'expeditious departure.' the tower chief explained the departure/noise considerations, while offering that no conflicts occurred. (Matter would be dropped.) our ensuing discussion offered the following suggestionsecond officerbservations. 1) tower chief observed 130 degree heading change should have seemed excessive -- many airports (iah, cle) require 180 degree heading change for departure. I offered that departure heading could be placed on pre departure clearance, rather than saying 'heading assigned by tower' on departure plate. 2) I observed that expeditious departure was requested and that it was in fact not necessary -- the increased noise level was distracting to the pilots. 3) the tower chief suggested that CRM could have also helped the heading confusion.

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Original NASA ASRS Text

Title: DC9 CREW AND TWR LCL CTLR HAD CONFUSION ABOUT THE HDG THE ACFT WAS TO FLY AFTER TKOF.

Narrative: INSTRUCTED TO TAXI INTO POS AND HOLD RWY 12R AND 'BE READY.' AFTER TAXIING INTO POS, ADVANCED THRUST LEVERS TO 1.2 EPR (DC9 HIGH IDLE) TO AID IN ANTICIPATED EXPEDITIOUS ACCELERATION. UPON HEARING 'ACR XXX CLRED FOR TKOF,' RAPIDLY ADVANCED THRUST TO TKOF POS. I BELIEVED THAT FO ACKNOWLEDGED HDG TO BE 250 DEGS. AFTER TKOF, CLBING THROUGH 400 FT, STARTED TURN, SWITCHED TO DEP CTL, FO QUESTIONED HDG WITH DEP AND WE WERE INSTRUCTED TO COME TO HDG 230 DEGS. AFTER ARR IN IAH, I WAS ASKED TO CALL STL TWR CHIEF. OUR DISCUSSION REVEALED THAT THE ASSIGNED DEP HDG WAS ACTUALLY 125 DEGS AND NO TFC WAS ON FINAL REQUIRING AN 'EXPEDITIOUS DEP.' THE TWR CHIEF EXPLAINED THE DEP/NOISE CONSIDERATIONS, WHILE OFFERING THAT NO CONFLICTS OCCURRED. (MATTER WOULD BE DROPPED.) OUR ENSUING DISCUSSION OFFERED THE FOLLOWING SUGGESTIONS/OBSERVATIONS. 1) TWR CHIEF OBSERVED 130 DEG HDG CHANGE SHOULD HAVE SEEMED EXCESSIVE -- MANY ARPTS (IAH, CLE) REQUIRE 180 DEG HDG CHANGE FOR DEP. I OFFERED THAT DEP HDG COULD BE PLACED ON PDC, RATHER THAN SAYING 'HDG ASSIGNED BY TWR' ON DEP PLATE. 2) I OBSERVED THAT EXPEDITIOUS DEP WAS REQUESTED AND THAT IT WAS IN FACT NOT NECESSARY -- THE INCREASED NOISE LEVEL WAS DISTRACTING TO THE PLTS. 3) THE TWR CHIEF SUGGESTED THAT CRM COULD HAVE ALSO HELPED THE HDG 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.