Commercial Fixed Wing
Flight Crew Total 9
Confusion; Situational Awareness; Communication Breakdown
ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Flight Crew Exited Penetrated Airspace; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action; Flight Crew Became Reoriented
Human Factors; Procedure
Over waypoint PERGA we requested climb from FL340 to FL360. PIARCO Control cleared us direct ANADA and to climb to FL360. Clearance was read back slowly and clearly and PIARCO said nothing. As aircraft climbed through FL350; another aircraft with a similar sounding call sign at FL360 several miles behind us called PIARCO and noted our converging altitudes. We began an immediate descent back to FL340 without further incident. PIARCO claimed he had not cleared us to climb; but we emphatically stated otherwise. Poor radio reception; poor controller English; and similar sounding callsigns were contributing factors. Closer attention to call signs and clearly understood clearance (by controller after readback by aircraft) must be maintained.
At FL355; both pilots noted the close proximity of the trailing aircraft and the climb was stopped. A descent was immediately made down to FL340 after clarification with ATC.Controller didn't respond after our clearance to climb was read back. If the Controller had responded; there would have been no confusion as to clearance or to whom it was issued (the climb clearance). Poor radio reception; poor radio quality and the lack of Controller acknowledgment was not helpful. Callsign similarity also led to clearance confusion.
Piarco Control granted the crew's climb request from FL340 to FL360. Another aircraft with a similar sounding call sign behind the climbing aircraft called Piarco to remind ATC their aircraft were converging at FL360 so the climbing crew descended to FL340.