Date: 201909
Local time of day: 1201-1800
Location: ZZZ.Tower, US
Flight conditions: Mixed
Light: Daylight
Aircraft: Gulfstream G280
Operator: Corporate
Operating under: Part 91
Flight plan: IFR
Mission: Ferry / Re-Positioning
Flight phase: Initial Climb
Airspace: Class D ZZZ
ATC / advisory: Tower ZZZ
Second aircraft: Beechcraft Twin Turboprop or Jet Undifferentiated or Other Model
Reporter organization: Corporate
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Human factors: Distraction; Confusion; Communication Breakdown; Situational Awareness
Anomaly: Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Air Traffic Control Separated Traffic; Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Returned To Clearance
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: Our aircraft; Aircraft X was cleared for departure from ZZZ. The crew had switched seats from the previous inbound leg to ZZZ and was preparing for the reposition leg to our home base at ZZZ1. We were cleared for departure from Runway XX and told to fly the ZZZ departure. The takeoff roll was initiated and the departure was flown. A similarly sounding tail-number departed shortly after we did [Aircraft Y]. The co-pilot and I flew the departure and we heard some commotion over the radio with Aircraft Y. As the Pilot Flying; and hand-flying at that stage of flight; I was paying more attention to the flight of the aircraft but could hear some confusion in the controllers regarding the similar sounding tails of the two aircraft (ours; and Aircraft Y). As a result of my hearing the similar sounding call-signs; I must have unintentionally delayed my required turnout at 800 ft. as per the departure. This resulted in our aircraft making the right hand turn to the desired heading specified in the departure at a later than anticipated time. This delayed turn then must have caused a loss of separation with the following Aircraft Y. [We were] given a heading to fly and we complied with the instruction. Aircraft Y was also given a heading to fly and to my knowledge they also complied. Nothing further was mentioned to our aircraft and I do not recall having heard anything being discussed over the radio about a loss of separation.I did not at the time believe that we (the pilots of Aircraft X) had done anything in error and was not aware that a loss of separation had occurred. I found out today that a loss of separation had occurred as a result of our delayed turn; and am writing this to bring attention to this matter. The corrective action that I would suggest for myself and my crew-member(s) is to maintain vigilance concerning heavy traffic environments and to verify; both as a crew; as well as with ATC; when particular instructions are given which aircraft those instructions are for; especially when there are similar sounding aircraft in the immediate vicinity of one another. Additionally; and most importantly regarding this particular issue; strict adherence to the published or given instructions as per what is discussed and expected by ATC will further alleviate issues with aircraft losing the desired amount of separation. As a continued practice; special emphasis will be given to altitudes; headings; and speed restrictions in high volume areas; specifically concerning the airport terminal area with arrivals and departures.




Synopsis: G280 Captain reported an accidental deviation from a SID resulted in a loss of separation.