Date: 201504
Local time of day: 1201-1800
Location: LEE.Airport, FL
Flight conditions: VMC
Weather elements / visibility: 20
Light: Daylight
Aircraft: Light Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class E ZJX
ATC / advisory: Center ZJX; TRACON JAX
Reporter organization: Air Carrier
Reporter function: Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown; Confusion; Distraction; Situational Awareness; Workload
Anomaly: ATC Issue All Types; Conflict Airborne Conflict
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Became Reoriented; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Airspace Structure; Procedure; Aircraft
Primary problem: Airspace Structure

Narrative: The short duration of the flight and an icing MEL; factors combined to cause 4000 MSL to be the practical and prudent altitude for this flight. While still on radar vectors; our aircraft was approximately 10 NM SW of LEE on an approximate bearing of 239 from the facility. We observed three hang glider craft very close aboard (approximately 200 meters) to our starboard side at or very near our altitude. Comment was made to JAX approach which stated they observed no traffic in our area. Of course; being a personal flight craft it would not be equipped with anything that could provide a radar contact. Over the course of approximately the next four miles my first officer and I observed at least a total twelve hang gliders with no others being as high as the initial 3 that were visually contacted. Geographically they were approximately immediately above the Palatlakaha Environmental and Agricultural Reserve. We adopted a high alert and scan of the environment in or about our direct flight path in attempt to be ready [to] avert any collision that may have been imminent however there was no other incident as narrowly missed as the initial observation. The gravity of the situation; for the purpose of a pilot safety report; was emphasized to JAX approach and they indicated relaying the information to Orlando ATC for dissemination. Initial proximity to the flight craft notwithstanding; (the initial contact would have provoked deliberate avoidance maneuvering had it been observed with any amount of lead time); no flight deviation was needed for the remainder of the encounter.Perhaps in conjunction with hang glider manufacturers; some manner of; at least; 'self-reporting' intended flights by these sport aviators should be developed. Something approximating a warning area that can be included in regular NOTAMs. The density of hang gliders in this event represented a clear and present danger to the safety of all involved. It seems an awareness program could be developed for the hang gliding community to improve safety margins. My aviation career experience demonstrates this to be an exceedingly rare event and thus does not necessarily dictate a mandatory program; however as a safety improvement factor in geographic areas that may be popular for these activities it may be a warranted and prudent effort.




Synopsis: An air carrier Captain at 4;000 feet near LEE reported numerous hang gliders at or near his altitude which posed a collision hazard. ATC had no information about the glider activity.