Date: 201412
Local time of day: 1201-1800
Location: ZID.ARTCC, IN
Aircraft: Light Transport; Low Wing; 2 Turbojet Eng
Flight plan: IFR
Flight phase: Climb
Airspace: Class A ZID
ATC / advisory: Center ZID
Second aircraft: Large Transport
Reporter organization: Government
Reporter function: Enroute
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Distraction; Confusion; Communication Breakdown; Situational Awareness
Anomaly: ATC Issue All Types; Conflict Airborne Conflict
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert
Contributing factors: Airport; Human Factors; Procedure
Primary problem: Procedure

Narrative: I accepted a handoff on Aircraft X climbing to FL400; I had no relevant traffic.  Exactly at the same time as the aircraft checked on to my frequency climbing out of 365 to 400; conflict activated with Aircraft Y; who was in ZDC airspace approximately 2 o'clock and 3 miles level at FL380.  My initial response to Aircraft X was 'Amend altitude; maintain FL370.'  The aircraft was climbing so rapidly that it could not stop in time; and climbed to FL378 with the Aircraft Y approximately 2 to 3 nm directly behind.  At that point separation had already been lost and the aircraft were at essentially the same altitude with Aircraft Y behind Aircraft X; so I wasn't sure whether it was better to resume the climb; initiate a descent; or just remain level; so I told the pilot were the traffic was.  The pilot then informed me that he had been climbing at a rate of approximately 6500 fpm.  Upon reflection; I realized that the previous sector had leveled Aircraft X for a couple of minutes for other traffic; and it appears to me that the pilot 'Zoom climbed' at more than 6000 fpm when given the clearance to FL400 by ZDC.  I don't think that ZDC expected the Learjet to climb nearly that rapidly and probably (my professional opinion) did not consider Aircraft Y as traffic. Because the Learjet 'Zoomed' into the climb so quickly; conflict alert processing could not give a timely alert to me or to ZDC until it was far too late.  This was a very serious situation that the ATC system; both with regard to controller expectation of pilot actions and with regard to automation features such as conflict alert; were not expecting.  If this 'Zoom climb' had begun just a couple of miles earlier; it could have resulted in a possible midair collision that perhaps even TCAS would have struggled to prevent. [Does TCAS expect aircraft near FL380 to be climbing at rates in excess of 6000 fpm?] Please note: None of the choices presented under the 'causal & contributing' factors seem to exactly fit this situation.  While I don't know that the pilot technically did anything wrong; clearly the rate of climb was completely out of conformance with what any controller would reasonably suspect in that situation; and so I checked the 'Non-conformance with a clearance: Altitude' box because it most closely describes what happened.In my opinion; this event was not a normal loss of separation; but was in fact a potentially deadly occurrence precipitated by a completely unexpected pilot action that the controllers and the automation were not prepared for. While controller training and an automation review (e.g. conflict alert; TCAS) might be warranted; this event should be brought to the attention of the pilot community through FAA Safety Briefings and the like; as an example of how such action can threaten safety.




Synopsis: ZID Controller reports of a loss of separation between two aircraft; one level and the other in what he calls a 'Zoom climb' of six thousand five hundred feet per minute.