Air carrier flight crew reported a NMAC with a VFR jet departing from an uncontrolled field just outside Class C airspace.
Synopsis
Air carrier flight crew reported a NMAC with a VFR jet departing from an uncontrolled field just outside Class C airspace.
Narrative
We were being vectored to intercept the final for Runway 26 at JAX; on approximately a 12 mile right dogleg at 2000 ft. I observed a jet rolling down the runway to the southwest at FHB; Fernandina Beach; an uncontrolled field; off our left side. As I watched I anticipated that he would be talking to the same Approach Controller we were. He lifted off and began a runway heading climb. At this time the Approach Controller asked if we had JAX in sight. We both looked right to confirm JAX still in sight. I looked back to the left and acquired the jet in a climbing right turn approximately 500 below us at 1 mile away. We then received a TA showing him 200 ft. below us. Our trajectory was such that he passed behind us at our altitude at a near distance; as we turned to the right to join final for Runway 26. I saw the nose of the jet with his lights illuminated at a close range. It looked like a cover photo from Flying Magazine. The Approach Controller stated he was not talking to him after issuing us the traffic warning.Had that aircraft had an inoperative transponder; an ADSB malfunction; visibility been different; or we been just a few second later; the outcome may have been different. He was in a climbing right turn; VFR; and most likely we were blocked from his vision by the upper cockpit ceiling of the other aircraft until he had closed to within a mile and was nearly 90 degrees to us in trajectories. I received a telephone number for Approach Control from Ground and initiated a call with the JAX Approach Manager. Person A called back later to say the distance was less than 1/2 a mile at our altitude; and this is an ongoing problem with this field. She also stated she would bookmark the tape at this spot and email me a copy. I have not received a copy as of this writing. In this situation a mid-air collision is highly probable. The traffic warning issued by JAX ATC; while as prompt as it could be; would not have assisted in acquiring or avoiding this traffic. We never heard the other aircraft on our frequency.Unfamiliarity with the local traffic area. As airlines pilots we only have our Jeppesen charts and flight release to provide very limited info in regards to this immediate traffic conflict. The pop ups occur directly below flight path. Visiting GA pilots. An immediate solution would be to issue a NOTAM prohibiting a pop up IFR departure from this field; as it should easily be within radio range of JAX. An additional item could be included on the ATIS/AWOS to prevent the pop up VFR departures from an immediate westerly turn on course due to traffic/ airspace conflict. Perhaps this airspace needs a redesign to prohibit the possibility of a mid-air collision or near miss in the future; such as NRB or CRG has. There has been a noticeable increase of traffic to this field in recent years.As well; the AFD should be updated to prohibited Right turn / West Turn departures into the conflicting JAX protected airspace. A Tower would be the safest course of action at FHB to mitigate this in normal business hours. I'm aware of the departure procedure or warnings issued to FHB traffic; at large; only locally. The traffic area to local JAX flyers does not reach the affluent fast traffic with pop up IFR or VFR westbound jets that are not familiar with this area. This conflict was too close to risk any single life we had on board; much less the 198 souls traveling collectively on us.
Second reporter narrative
On vectors to final for Runway 26 JAX in VFR conditions Captain stated he observed a jet at Fernanadia Airport on the takeoff roll to our left. From my seat I could not observe any of this. Shortly following his observation JAX Approach asked if we had the JAX airport in sight. We both looked to 2 o'clock; confirmed JAX was in sight; and Approach cleared us for the visual approach to Runway 26. Immediately after clearance the Captain observed the other jet traffic in a climbing right turn tracking on course to collide with us or near miss at best. Simultaneously JAX Approach issued a traffic alert; and our TCAS system generated a TA advisory. No RA was generated; but it was very close and behind us traffic passed.It was afternoon so the sun may have impaired the other aircraft pilot's vision; and acquiring a visual for him may have been blocked by his aircraft's upper panel. The Captain called JAX Approach and was told the distance between the two aircraft was .5 mi. The climbing aircraft was a VFR popup so prohibiting a climbing westward turn on takeoff from Fernandia airport would be a good idea. JAX Approach informed the Captain this is a trouble spot for this reason. The proximity to JAX I'm sure would allow radio contact on the ground from JAX Approach so this could be controlled better.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.