B767-300 and 300 ER
Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Training / Qualification; Confusion; Situational Awareness; Communication Breakdown
ATC Issue All Types; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance
Flight Crew Returned To Clearance
Procedure; Human Factors
On mid-level climb out from ZZZ. Preceding departure traffic was 20 plus miles ahead and climbing; but at a slower airspeed. LA Center cleared us to FL340 and slow to 280 knots; we were registering approximately 315 knots for the climb. The airplane pitched rapidly for FL340 as it slowed and pitched to attain 280 knots climb speed. Center then requested we level and stop climb at FL180. We received this radio request as the airplane was passing 18;500 ft. and climbing rapidly towards FL340! We advised we were passing and thru FL180; on our way for FL340. Center requested we descend back to FL180. We leveled at FL190 and began the descent back to FL180 as quickly as safely possible. We then proceeded at FL180 for a short period of time; and were then re-cleared to FL340. Nothing adverse was observed and no TCAS warnings or resolutions occurred. We proceeded to ZZZ1 without further incident. This report is to establish the sequence of events; should there be any issues with our compliance with ATC instructions. ATC unreasonable level off request; and non-timely manner of request delivery to flight-crew. Note rate of aircraft climb to clearance altitude; and deliver level off change requests in a timely; attainable; reasonable performance fashion for flight-crew.
B767 pilot reported being unable to comply with an ATC request; resulting in an altitude deviation.