Date: 201808
Local time of day: 1201-1800
Location: ZBW.ARTCC, NH
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: Small Aircraft; High Wing; 1 Eng; Fixed Gear
Operator: FBO
Operating under: Part 91
Flight plan: VFR
Mission: Skydiving
Flight phase: Cruise
Airspace: Class E ZBW
ATC / advisory: Center ZBW
Second aircraft: Small Aircraft
Reporter organization: FBO
Reporter function: Single Pilot; Pilot Flying
Reporter qualification: Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Commercial
Human factors: Communication Breakdown
Anomaly: ATC Issue All Types; Conflict Airborne Conflict
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Took Evasive Action
Contributing factors: Human Factors; Environment - Non Weather Related; Procedure
Primary problem: Human Factors

Narrative: I was pilot flying on a recent skydive flight. This was a specially authorized flight by the FAA; therefore outside the area we typically fly and skydivers jump from. We initially landed at a public non-towered airport; but were asked by individuals on the ground (unclear if they were airport managers or what their title was) not to use the airport as a base for the jump run (something about a recent skydiving incident and not wanting to draw additional attention by letting us launch from there too); so we moved to a nearby towered airport. We were about 1.5 hours early; so had plenty of time to coordinate with the airport manager on the ground; and the Class D Tower and communicate our intentions to fly jump run outside their airspace in Class E at 4;500 MSL. The professionals at this Class D airport were very inquisitive (asked lots of questions to make sure they fully understood our intentions and that everyone was on the same page); and coordinated with Approach control for our handoff for jump run. Accordingly; due to the correct filing and authorization from the FAA; the NOTAM filed with FSS; and clear communication with the relevant ATC facilities; we truly felt we had done everything 'Pre' flight to make sure everyone knew our intentions; and I had a heightened sensitivity to the importance of this communication because we launched out of this busy Class D airport which typically does not handle parachute operations and I considered that the local approach controller may not be as comfortable with the operation as our local approach controller at the airport we routinely fly skydivers from.The safety issue that concerns me and generates this report is what happened during the jump run. I visually cleared the area and communicated about 3 or 4 times with Approach control the altitude and timing of jump run; including a radio call about 1 minute prior to jump operations. If I recall correctly; approach control did confirm the '1 minute prior' message and relayed that over frequency. The skydivers also visually cleared the area before jumping; and after all three launched; Approach asked me to hold over the area and wait until they were all on the ground so I could report and they could broadcast an 'all-clear' on frequency. As the next minute or two elapsed; I observed Aircraft Y fly north to south and directly through the area I had dropped the jumpers. This location was several miles south of the non-towered; Class E airport we had originally tried to launch from; and I had seen that distinct aircraft on the ground there when we first landed. Because this was a specially authorized flight; and [it was for a special occasion] on the ground; our skydivers had prepared extravagant visual displays (smoke streams; trailing flags; lots of color; etc) and were therefore - in my mind - completely impossible to miss at this stage; with their canopies deployed. To my extreme consternation; I observed Aircraft Y continue a visual flight path directly through the path of the jump operation; with no lateral deviation for clearance from the jumpers whatsoever. I didn't sense the pilot climbing or descending to put a visual distance between himself and the jumpers; and at no time did ATC announce to me; either before or after dropping the jumpers; that this traffic was in the vicinity. I would estimate his altitude to be about 3000 ft; and horizontal and vertical distance from the jumpers to be within 500 ft each; but can't be entirely sure. Given that we had originally landed at this non-towered airport; and had filed NOTAMs appropriately; I have a lot of trouble imagining this pilot was unaware of our jump operations south of the field (maybe 5 miles south or so). I believe he wasn't on frequency with ATC; otherwise I would have expected to hear him while I was communicating with Approach control. And last; even if the pilot didn't know we had authorization to do this jump run during a very specific window of time;hadn't seen us when we first landed there; and wasn't talking to ATC - I have a lot of trouble imagining he did not visually acquire our skydivers as they descended under canopy - again; due to their extremely distinct visual and colorful profile.From a safety and action perspective; my best guess is that ATC either had too high a workload; or was insufficiently familiar with parachute operations; to identify the need for providing that traffic alert to me. When I made my last radio call of '1 minute prior' it would have made a huge difference if ATC had notified me of traffic north of our position; 3000 ft; heading directly over our jump run area. I am keenly aware of my PIC responsibility to visually clear the area before dropping jumpers; but in a case where I do a visual scan and do not pick up traffic; ATC alerts of traffic trending to our position are my last line of defense. Last; I don't want to be put in the position of determining what the Aircraft Y pilot's intentions were; but I cannot rule out the possibility that he was intentionally trying to intimidate our operation. In essence; my responsibility for the safety of flight and my skydivers; and knowledge that this special operation was likely to be unfamiliar to local ATC facilities; made me hyper sensitive to providing clear and frequent communication; and I felt let down that I didn't get that traffic alert in return.




Synopsis: Pilot of a single engine piston aircraft in a parachute jumping event reported an airborne conflict with an aircraft intruding into the jump airspace.