Narrative:

Small aircraft X departed atl runway 27R. Told to turn left heading 200 degrees. Small aircraft X did not turn and then was instructed to fly heading 180 degrees. Small aircraft X then started a right turn and advised he lost his gyro. Air carrier Y was airborne off the west end of runway 26L. TA was issued to both aircraft. Air carrier Y was at 2500 ft when they passed. Small aircraft X was at 3000 ft. Supplemental information from acn 257749: small aircraft X departed runway 27R at atl. Air carrier Y departed 26L. Small aircraft X wa turned sbound and switched to departure. Apparently, small aircraft X lost or never set gyro and made a right turn to cross air carrier Y departure course. On initial contact with air carrier Y I issued TA 'maintain 2000' and issued traffic. Air carrier Y leveled his climb at 2500 ft with small aircraft X at 3000 ft. Both aircraft were in the clouds and never saw each other. Supplemental information from acn 257747: air carrier Y on departure from atl runway 26L. As we turned to 285 degrees at the MM we were alerted by a TCASII advisory. Atl departure advised us of traffic at 12 O'clock/3000 ft. TCASII issued an RA to monitor vertical speed. As we leveled at 2500 ft MSL, the TCASII resolution was a 2000 FPM descent. I made a shallow descent until clear of the conflict. The entire event took place in seconds, the bogey was not sighted.

Related reports:

Google
 

Original NASA ASRS Text

Title: SMA X ACFT EQUIP PROB GYRO WRONG DIRECTION TURN HAD LTSS FROM ACR Y TCASII RA. EVASIVE ACTION TAKEN. PLTDEV.

Narrative: SMA X DEPARTED ATL RWY 27R. TOLD TO TURN L HDG 200 DEGS. SMA X DID NOT TURN AND THEN WAS INSTRUCTED TO FLY HDG 180 DEGS. SMA X THEN STARTED A R TURN AND ADVISED HE LOST HIS GYRO. ACR Y WAS AIRBORNE OFF THE W END OF RWY 26L. TA WAS ISSUED TO BOTH ACFT. ACR Y WAS AT 2500 FT WHEN THEY PASSED. SMA X WAS AT 3000 FT. SUPPLEMENTAL INFO FROM ACN 257749: SMA X DEPARTED RWY 27R AT ATL. ACR Y DEPARTED 26L. SMA X WA TURNED SBOUND AND SWITCHED TO DEP. APPARENTLY, SMA X LOST OR NEVER SET GYRO AND MADE A R TURN TO CROSS ACR Y DEP COURSE. ON INITIAL CONTACT WITH ACR Y I ISSUED TA 'MAINTAIN 2000' AND ISSUED TFC. ACR Y LEVELED HIS CLB AT 2500 FT WITH SMA X AT 3000 FT. BOTH ACFT WERE IN THE CLOUDS AND NEVER SAW EACH OTHER. SUPPLEMENTAL INFO FROM ACN 257747: ACR Y ON DEP FROM ATL RWY 26L. AS WE TURNED TO 285 DEGS AT THE MM WE WERE ALERTED BY A TCASII ADVISORY. ATL DEP ADVISED US OF TFC AT 12 O'CLOCK/3000 FT. TCASII ISSUED AN RA TO MONITOR VERT SPD. AS WE LEVELED AT 2500 FT MSL, THE TCASII RESOLUTION WAS A 2000 FPM DSCNT. I MADE A SHALLOW DSCNT UNTIL CLR OF THE CONFLICT. THE ENTIRE EVENT TOOK PLACE IN SECONDS, THE BOGEY WAS NOT SIGHTED.

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.