Narrative:

On departure from dfw passing 6000 ft a B757 ahead of us on a different frequency called back to warn us of 'strong moderate turbulence' on climb out. When an aircraft flips back to a previous frequency to warn you; you know you had better take it seriously. So I directed the flight attendants to stay seated and directed the copilot to accelerate to 280 KIAS turbulence pen speed. We advised departure we would be at 280 KIAS due to turbulence; and at 11000 ft we encountered strong moderate turbulence. Departure told us to slow to 260 KIAS and we advised them we were unable due to turbulence. He sent us to a different frequency. That controller then told us to slow to 250 KIAS. We told him we were unable due to turbulence. He came back in a 'strong' voice and told us rather directly to slow to 250 KIAS. I told him again strongly I was unable to slow due to turbulence. Sensing he couldn't find a solution to his spacing problem; I suggested he put us on a vector. He did. As this controller seemed unaware of aircraft performance issues in turbulence; I attempted to briefly educate him before I left the frequency. He didn't seem very receptive and stated I should declare an emergency if I refused to follow his instructions. It doesn't seem very practical to declare an emergency every time I am unable to comply with an instruction. Perhaps a better idea is to provide controllers who work separation critical areas like class B approach/departure areas with training in aircraft performance in turbulence. Another idea is to increase spacing when aircraft report moderate turbulence. This will allow controllers more 'safety factor.' I understand the capacity needs of airports such as dfw; but these don't override safety. Trying to meet capacity needs by spacing aircraft too close together in turbulence is sure to lead to more conflicts such as this one.

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Original NASA ASRS Text

Title: TURB PENETRATION SPD OF B737-800 CONFLICTS WITH DEP CTLR SPACING REQUIREMENTS.

Narrative: ON DEP FROM DFW PASSING 6000 FT A B757 AHEAD OF US ON A DIFFERENT FREQ CALLED BACK TO WARN US OF 'STRONG MODERATE TURB' ON CLBOUT. WHEN AN ACFT FLIPS BACK TO A PREVIOUS FREQ TO WARN YOU; YOU KNOW YOU HAD BETTER TAKE IT SERIOUSLY. SO I DIRECTED THE FLT ATTENDANTS TO STAY SEATED AND DIRECTED THE COPLT TO ACCELERATE TO 280 KIAS TURB PEN SPD. WE ADVISED DEP WE WOULD BE AT 280 KIAS DUE TO TURB; AND AT 11000 FT WE ENCOUNTERED STRONG MODERATE TURB. DEP TOLD US TO SLOW TO 260 KIAS AND WE ADVISED THEM WE WERE UNABLE DUE TO TURB. HE SENT US TO A DIFFERENT FREQ. THAT CTLR THEN TOLD US TO SLOW TO 250 KIAS. WE TOLD HIM WE WERE UNABLE DUE TO TURB. HE CAME BACK IN A 'STRONG' VOICE AND TOLD US RATHER DIRECTLY TO SLOW TO 250 KIAS. I TOLD HIM AGAIN STRONGLY I WAS UNABLE TO SLOW DUE TO TURB. SENSING HE COULDN'T FIND A SOLUTION TO HIS SPACING PROB; I SUGGESTED HE PUT US ON A VECTOR. HE DID. AS THIS CTLR SEEMED UNAWARE OF ACFT PERFORMANCE ISSUES IN TURB; I ATTEMPTED TO BRIEFLY EDUCATE HIM BEFORE I LEFT THE FREQ. HE DIDN'T SEEM VERY RECEPTIVE AND STATED I SHOULD DECLARE AN EMER IF I REFUSED TO FOLLOW HIS INSTRUCTIONS. IT DOESN'T SEEM VERY PRACTICAL TO DECLARE AN EMER EVERY TIME I AM UNABLE TO COMPLY WITH AN INSTRUCTION. PERHAPS A BETTER IDEA IS TO PROVIDE CTLRS WHO WORK SEPARATION CRITICAL AREAS LIKE CLASS B APCH/DEP AREAS WITH TRAINING IN ACFT PERFORMANCE IN TURB. ANOTHER IDEA IS TO INCREASE SPACING WHEN ACFT RPT MODERATE TURB. THIS WILL ALLOW CTLRS MORE 'SAFETY FACTOR.' I UNDERSTAND THE CAPACITY NEEDS OF ARPTS SUCH AS DFW; BUT THESE DON'T OVERRIDE SAFETY. TRYING TO MEET CAPACITY NEEDS BY SPACING ACFT TOO CLOSE TOGETHER IN TURB IS SURE TO LEAD TO MORE CONFLICTS SUCH AS THIS ONE.

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