Small Transport; Low Wing; 2 Turbojet Eng
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 21
Communication Breakdown
ATC Issue All Types; Conflict Airborne Conflict; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance
Air Traffic Control Provided Assistance; Flight Crew Returned To Clearance
Aircraft; Human Factors; Procedure
Was working the LOGAN and the western half of the BURBN which overlays the LOGAN sector.  Not much going on when was relieved by the training team.  When doing the overlap; the Developmental asked for a D-Side; since I already knew what was going on I sat on the D-Side.  Developmental was quickly falling behind and the instructor had to take over the frequency.  This was I believe the Developmentala's 2nd day of training on a R-Side position in her career. Aircraft Y was requesting FL400 from FL380 due to chop.  Aircraft X was already pointed out to the RAN(47) sector going to BRO and points south into MEXICO.  The instructor coordinated with RAN to climb reference Aircraft Y that was coming our way from RAN going to the east coast from DEN. It was determined that in 4 minutes the two aircraft would lose separation if not level at 400; so the instructor inquired how long it would take Aircraft X to be level. The pilot responded that it would take 2 1/2 minutes to be level.  The instructor then climbed with the restriction to be level in 2 1/2 minutes of which the pilot read back and acknowledged the restriction.  The instructor then went about shipping and working the sector as it was now becoming moderately busy with aircraft trying to check on.  I was busy making and taking handoffs and coordinating info with other sectors.About 1 1/2 [minutes] into the climb Aircraft X was out of 393 and doing well when it all changed.  For some reason Aircraft X climb started to drastically reduce and the instructor tried several times to get a response from the Aircraft as to what his abilities were.  Eventually after getting no answer the instructor cleared Aircraft X to turn 20 degrees left to buy himself an extra minute for Aircraft X to be level.  The pilot acknowledged the turn and then I received a call from the RAN sector as to what our intention was for the Aircraft X and Aircraft Y situation.  I stated we're going left and RAN stated they were going left as well.  In an effort to get Aircraft X to turn tighter the instructor then issued a 090 heading to Aircraft X.The pilot acknowledged and started what appeared to be a very slow turn.  For some reason the highest altitude I saw was 396 then Aircraft X started a descent.  When the instructor asked the pilot what he was doing the pilot stated he could not turn and climb at the same time.  The pilot stated he was going back down to FL390; of which he never had a clearance to do so.  This to the best of knowledge is what happened; but keep in mind I was doing coordination with other sectors at the same time so some of the above events may be off.In my belief a big part of what happened is in our training program.  If I was still working the sector I would have not needed a D-Side and probably this event would never have occurred.  The same is true if the instructor had been the one to relieve me.  This is not to say the Developmental can or cannot do the job; but she was getting way behind the power curve from the very second she took over for me and never got caught up. The instructor was only trying to let her get caught up in a teaching role; that from time to time in very small spurts a lot happens at once and you have to learn duty priority.  The overall effort to make everyone who comes into our building a CPC I believe has led to many people who are not equipped to handle a mod/heavy workloads sporadically without it compromising the sector's safety and efficiency.  I know I'm considered old school; but when someone who is [age given] and been doing this job for some time and is more efficient than even some of the junior CPC's in their late 20's and early 30's; this is a concern to me.  When I'm gone in a few years and these other controllers are the ones who are left; where does that put us?  These are the people who will be expected to do all the training and if we don't take some steps to properly screen out the ones who don't have the speed to keep upwhere does that leave us?
I was performing OJT at LOGAN 34R. Aircraft X was on frequency level at FL380. Aircraft X had been pointed out to Sector 47 at FL380 direct BRO and was flashing at sector I99. Aircraft X requested FL400. I responded that I had his request and coordinated with Sector 47 to apreq the climb to FL400.  Sector 47 referenced Aircraft Y at FL390 westbound.  My trainer told me to reply 'Roger' and we discontinued the call.  We ran out the vector lines and the point of conflict would have been between 3-4 minutes.  My trainer then took over the frequency and asked what Aircraft X's rate of climb would be.  Aircraft X stated they could be level in 2-2 1/2 minutes.  My trainer cleared Aircraft X to climb to FL400 and to be level in 2 1/2 minutes or less and report level.About 3 minutes later conflict alert went off.  My trainer asked Aircraft Y their altitude.  Aircraft X stated FL393.  My trainer issued a ninety degree heading via a left turn.  Aircraft Y appeared to have turned twenty degrees left to avoid Aircraft X.  Sector 47 still had control and was talking to Aircraft Y. After a 1 minute or so; Aircraft X data block reflected that they were descending and in a slow left turn.  My trainer asked them what they were doing.  Aircraft X stated that they could not climb and turn at the same time.  My trainer issued Aircraft X direct BRO when level at FL400.When the pilot realized he couldn't comply with the clearance he should have immediately stated it and his climb should have been altered and or turns could have been used to prevent conflict alert.
ZAU ARTCC controllers describe a training session where the instructor had to take over; with two aircraft that were on opposite courses; and one pilot finally advising the Controller that he couldn't climb and turn at the same time.