Narrative:

Upon departure from dfw, we were on radar vectors at 4000 ft over dal when a B737 departed dal. The B737 was assigned 4000 ft as well. We were level with airspeed at 240 KTS coming up on the B737 at his 6 O'clock position. Due to the long duty day and minimal time between flts, my copilot placed the TCASII switch in 'TA only.' if the TCASII had been set normally we would have received an RA and avoided some nasty wake turbulence. I feel the controller was negligent in placing a 240 KT level aircraft behind a climbing B737, even though he had just leveled, his speed was less than ours. Callback conversation with reporter revealed the following information: the reporter said that he did not anticipate that the B737 would not be continuing its climb. Instead this was a maintenance ferry that had leveled at 4000 ft for the short, low speed cruise to the maintenance base. The reporter also said that the flight crew was fatigued and complacent making several small procedural errors prior to this. The wake encounter was a wakeup call. The event only lasted a couple of seconds according to the captain, but he and his first officer talked about it for 2 days. Just prior to hitting the wake the captain said that he told himself that he was probably going to, then did. He disconnected the autoplt, advanced the throttles and flew out of the wake. The captain said that he had had some experience with formation flying before this.

Google
 

Original NASA ASRS Text

Title: AN ACR FLC CLOSES WITHIN 2000 FT INTRAIL OF AN ACR B737 AND ENCOUNTERS THE WAKE. THE TRAILING FLC EXPECTED THE B737 TO CONTINUE ITS DEP CLB.

Narrative: UPON DEP FROM DFW, WE WERE ON RADAR VECTORS AT 4000 FT OVER DAL WHEN A B737 DEPARTED DAL. THE B737 WAS ASSIGNED 4000 FT AS WELL. WE WERE LEVEL WITH AIRSPD AT 240 KTS COMING UP ON THE B737 AT HIS 6 O'CLOCK POS. DUE TO THE LONG DUTY DAY AND MINIMAL TIME BTWN FLTS, MY COPLT PLACED THE TCASII SWITCH IN 'TA ONLY.' IF THE TCASII HAD BEEN SET NORMALLY WE WOULD HAVE RECEIVED AN RA AND AVOIDED SOME NASTY WAKE TURB. I FEEL THE CTLR WAS NEGLIGENT IN PLACING A 240 KT LEVEL ACFT BEHIND A CLBING B737, EVEN THOUGH HE HAD JUST LEVELED, HIS SPD WAS LESS THAN OURS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR SAID THAT HE DID NOT ANTICIPATE THAT THE B737 WOULD NOT BE CONTINUING ITS CLB. INSTEAD THIS WAS A MAINT FERRY THAT HAD LEVELED AT 4000 FT FOR THE SHORT, LOW SPD CRUISE TO THE MAINT BASE. THE RPTR ALSO SAID THAT THE FLC WAS FATIGUED AND COMPLACENT MAKING SEVERAL SMALL PROCEDURAL ERRORS PRIOR TO THIS. THE WAKE ENCOUNTER WAS A WAKEUP CALL. THE EVENT ONLY LASTED A COUPLE OF SECONDS ACCORDING TO THE CAPT, BUT HE AND HIS FO TALKED ABOUT IT FOR 2 DAYS. JUST PRIOR TO HITTING THE WAKE THE CAPT SAID THAT HE TOLD HIMSELF THAT HE WAS PROBABLY GOING TO, THEN DID. HE DISCONNECTED THE AUTOPLT, ADVANCED THE THROTTLES AND FLEW OUT OF THE WAKE. THE CAPT SAID THAT HE HAD HAD SOME EXPERIENCE WITH FORMATION FLYING BEFORE THIS.

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.