JS41 crew misunderstand assigned heading and converge on a BE40 that had departed the same runway.

Attributes
ACN	551102
Time
Date	200206
Day	Wed
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : iad.airport
State Reference	VA
Altitude	msl single value : 4000
Aircraft 1
Controlling Facilities	tower : iad.tower
Operator	common carrier : air carrier
Make Model Name	Jetstream 41
Operating Under FAR Part	Part 135
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Aircraft 2
Controlling Facilities	tower : iad.tower
Operator	general aviation : corporate
Make Model Name	Beechjet 400
Operating Under FAR Part	Part 91
Flight Phase	climbout : intermediate altitude
Flight Plan	IFR
Person 1
Affiliation	government : faa
Function	controller : approach
Experience	controller military : 4 controller radar : 5 controller time certified in position1 : 3
ASRS Report	551102
Person 2
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Events
Anomaly	conflict : airborne critical non adherence : published procedure other anomaly other
Independent Detector	atc equipment : conflict alert atc equipment other atc equipment : radar other controllera
Resolutory Action	controller : issued new clearance
Miss Distance	horizontal : 6000 vertical : 200
Supplementary
Problem Areas	Flight Crew Human Performance ATC Human Performance
Primary Problem	ATC Human Performance
Air Traffic Incident	Operational Error

Narrative:

The JS41 departs runway 30 heading 280 degrees and for 3 mi approximately before I turned him to direct csn. A BE40 departed afterward, turning to a 260 degree heading. I turned the BE40 to a 190 degree heading and climbed him to 10000 ft. The JS41 going to csn was on approximately 230-240 degree heading. I issued a right turn to 270 degrees and heard a readback partially blocked with '70' in it. I watch, expecting the aircraft to separate further, and they didn't. They continued to converge. I asked about the JS41 heading and he said I told him 170 degrees and said that's what he read back. I reissued the 270 degree heading, but the BE40 passed by the JS41 and said he never saw the JS41.

Original NASA ASRS Text

Title: JS41 CREW MISUNDERSTAND ASSIGNED HDG AND CONVERGE ON A BE40 THAT HAD DEPARTED THE SAME RWY.

Narrative: THE JS41 DEPARTS RWY 30 HDG 280 DEGS AND FOR 3 MI APPROX BEFORE I TURNED HIM TO DIRECT CSN. A BE40 DEPARTED AFTERWARD, TURNING TO A 260 DEG HDG. I TURNED THE BE40 TO A 190 DEG HDG AND CLBED HIM TO 10000 FT. THE JS41 GOING TO CSN WAS ON APPROX 230-240 DEG HDG. I ISSUED A R TURN TO 270 DEGS AND HEARD A READBACK PARTIALLY BLOCKED WITH '70' IN IT. I WATCH, EXPECTING THE ACFT TO SEPARATE FURTHER, AND THEY DIDN'T. THEY CONTINUED TO CONVERGE. I ASKED ABOUT THE JS41 HDG AND HE SAID I TOLD HIM 170 DEGS AND SAID THAT'S WHAT HE READ BACK. I REISSUED THE 270 DEG HDG, BUT THE BE40 PASSED BY THE JS41 AND SAID HE NEVER SAW THE JS41.

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.