Narrative:

The captain was flying and the aircraft was on autoplt and being controled by the pms computer. We were climbing out of FL200 and cleared to deviate east of our direct lakeland VOR heading of 320 degrees. The low altitude center controller requested we slow from our speed of 300 KTS to 250 KTS. He said it was for the next sector's request. 250 KTS was entered into the pms and the aircraft started to climb at 4000 FPM, burning off speed to slow to 250 KTS. We were then handed off to the next controller. I checked on and informed controller that we were deviating east, and assigned 250 KTS. We were cleared to FL350. Climbing out of FL230, I requested normal speed. The controller cleared us to resume normal speed. The captain selected normal climb in the pms, and the aircraft pitched nose down to 500 FPM climb. We accelerated back to 300 KTS. Not 15 seconds later, as we were climbing at 500 FPM through FL250, the controller came on in a very urgent tone of voice and gave us an immediate right turn to 090 degrees. The controller then gave air carrier Y an immediate left turn. The controller also told us to expedite through FL260. We complied with both orders. After complaining about WX, air carrier Y did also. As we were turning right, we saw a target at our altitude about 5 mi away at our 11 O'clock position on the TCASII. This was as close as we came to air carrier Y and we received no advisories from TCASII. Upon asking the controller what was going on, the controller told us that we passed 6 mi from the other aircraft, and that when we were issued normal speed, the controller did not expect us to stop climbing. I believe that the problem here was that the controller did not anticipate that we would shallow our rate of climb in order to accelerate to normal speed. I would hope that this basic concept of rates of climb/descent versus airspeed would be taught to controllers. The controller should have cleared us to resume normal speed out of FL260, since we had approaching conflicting traffic at FL250. We as a flight crew had no way to know this, and I am aware of no requirement to inform ATC of climb performance unless it drops below 500 FPM. Supplemental information from acn 385615: air carrier Y departed fll for stl XX03 on climb out with ZMA. We were instructed to climb out at 250 KTS (reduce from our opt climb speed on our pms 310 KTS). We complied and were handed off to the next sector. ZMA cleared us to FL350. As we passed through FL240 we requested normal climb speed. At about FL245, ZMA said 'resume normal climb speed.' I then selected opt climb and our climb shallowed to about 500 FPM as the aircraft attempted to accelerate to opt speed (about 290-300 KTS). ZMA was giving other traffic vectors around a storm ahead of avoid turbulence on the west side. I queried the controller where the turbulence was and the controller said, 'air carrier Y turn right immediately.'

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Original NASA ASRS Text

Title: 2 ACRS WERE ON DEP, RESTR TO 250 KTS. BOTH ACRS REQUESTED AND RECEIVED NORMAL CLB SPD RATES, WITH VECTORS DEV AROUND WX. ZMA CTLR DID NOT EXPECT ACR CLB RATES TO CHANGE AND HAD TO VECTOR TO OBTAIN AND ENSURE SEPARATION.

Narrative: THE CAPT WAS FLYING AND THE ACFT WAS ON AUTOPLT AND BEING CTLED BY THE PMS COMPUTER. WE WERE CLBING OUT OF FL200 AND CLRED TO DEVIATE E OF OUR DIRECT LAKELAND VOR HDG OF 320 DEGS. THE LOW ALT CTR CTLR REQUESTED WE SLOW FROM OUR SPD OF 300 KTS TO 250 KTS. HE SAID IT WAS FOR THE NEXT SECTOR'S REQUEST. 250 KTS WAS ENTERED INTO THE PMS AND THE ACFT STARTED TO CLB AT 4000 FPM, BURNING OFF SPD TO SLOW TO 250 KTS. WE WERE THEN HANDED OFF TO THE NEXT CTLR. I CHKED ON AND INFORMED CTLR THAT WE WERE DEVIATING E, AND ASSIGNED 250 KTS. WE WERE CLRED TO FL350. CLBING OUT OF FL230, I REQUESTED NORMAL SPD. THE CTLR CLRED US TO RESUME NORMAL SPD. THE CAPT SELECTED NORMAL CLB IN THE PMS, AND THE ACFT PITCHED NOSE DOWN TO 500 FPM CLB. WE ACCELERATED BACK TO 300 KTS. NOT 15 SECONDS LATER, AS WE WERE CLBING AT 500 FPM THROUGH FL250, THE CTLR CAME ON IN A VERY URGENT TONE OF VOICE AND GAVE US AN IMMEDIATE R TURN TO 090 DEGS. THE CTLR THEN GAVE ACR Y AN IMMEDIATE L TURN. THE CTLR ALSO TOLD US TO EXPEDITE THROUGH FL260. WE COMPLIED WITH BOTH ORDERS. AFTER COMPLAINING ABOUT WX, ACR Y DID ALSO. AS WE WERE TURNING R, WE SAW A TARGET AT OUR ALT ABOUT 5 MI AWAY AT OUR 11 O'CLOCK POS ON THE TCASII. THIS WAS AS CLOSE AS WE CAME TO ACR Y AND WE RECEIVED NO ADVISORIES FROM TCASII. UPON ASKING THE CTLR WHAT WAS GOING ON, THE CTLR TOLD US THAT WE PASSED 6 MI FROM THE OTHER ACFT, AND THAT WHEN WE WERE ISSUED NORMAL SPD, THE CTLR DID NOT EXPECT US TO STOP CLBING. I BELIEVE THAT THE PROB HERE WAS THAT THE CTLR DID NOT ANTICIPATE THAT WE WOULD SHALLOW OUR RATE OF CLB IN ORDER TO ACCELERATE TO NORMAL SPD. I WOULD HOPE THAT THIS BASIC CONCEPT OF RATES OF CLB/DSCNT VERSUS AIRSPD WOULD BE TAUGHT TO CTLRS. THE CTLR SHOULD HAVE CLRED US TO RESUME NORMAL SPD OUT OF FL260, SINCE WE HAD APCHING CONFLICTING TFC AT FL250. WE AS A FLC HAD NO WAY TO KNOW THIS, AND I AM AWARE OF NO REQUIREMENT TO INFORM ATC OF CLB PERFORMANCE UNLESS IT DROPS BELOW 500 FPM. SUPPLEMENTAL INFO FROM ACN 385615: ACR Y DEPARTED FLL FOR STL XX03 ON CLBOUT WITH ZMA. WE WERE INSTRUCTED TO CLB OUT AT 250 KTS (REDUCE FROM OUR OPT CLB SPD ON OUR PMS 310 KTS). WE COMPLIED AND WERE HANDED OFF TO THE NEXT SECTOR. ZMA CLRED US TO FL350. AS WE PASSED THROUGH FL240 WE REQUESTED NORMAL CLB SPD. AT ABOUT FL245, ZMA SAID 'RESUME NORMAL CLB SPD.' I THEN SELECTED OPT CLB AND OUR CLB SHALLOWED TO ABOUT 500 FPM AS THE ACFT ATTEMPTED TO ACCELERATE TO OPT SPD (ABOUT 290-300 KTS). ZMA WAS GIVING OTHER TFC VECTORS AROUND A STORM AHEAD OF AVOID TURB ON THE W SIDE. I QUERIED THE CTLR WHERE THE TURB WAS AND THE CTLR SAID, 'ACR Y TURN R IMMEDIATELY.'

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.