Date: 201511
Local time of day: 1201-1800
Location: HCF.TRACON, HI
Flight conditions: VMC
Light: Daylight
Aircraft: Light Transport; Low Wing; 2 Turboprop Eng
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Final Approach
Airspace: Class D LIH
ATC / advisory: TRACON HCF
Second aircraft: Medium Large Transport; Low Wing; 2 Turbojet Eng
Reporter organization: Government
Reporter function: Approach; Local
Reporter qualification: Air Traffic Control Fully Certified
Human factors: Situational Awareness
Second reporter function: Captain; Pilot Flying
Anomaly: Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Procedure; Human Factors; Airspace Structure; Weather
Primary problem: Procedure

Narrative: Aircraft X was on a visual approach following Aircraft Y. Aircraft X asked for a three sixty degree turn for spacing because Aircraft Y went into a cloud and Aircraft X lost sight of the preceding aircraft. I instructed Aircraft X to turn left heading 180 for spacing. I had less than 3 miles between the aircraft. Aircraft Y was on approach 030 descending. I'm not positive the aircraft lost separation but they may have.The Aircraft X pilot did not sound confident in his requests. I should have been more positive in my control of the situation. I should have been suspicious of the weather and Aircraft X's ability to follow Aircraft Y when the Aircraft Y pilot reported being IMC. Sector 2 is an oceanic sector that also deals with oceanic non radar separation as well as approach control. Recently it seems the radar assist has been combined during the day when it probably should not be. It may be a staffing issue.


Second narrative: We were cleared to descend and for the visual approach into Lihue runway 35; with runway 3 on request. While descending through approximately seven thousand feet; Aircraft Y overtook us. We were descending at approximately 250 knots; while the TCAS showed the traffic at two thousand feet above us and holding altitude. After passing us the traffic reduced its airspeed and was cleared for the ILS Approach. After being cleared for the Visual Approach before the traffic was cleared for the ILS Approach; were instructed to follow the traffic to the airport. We complied and started to reduce airspeed and open the distance between ourselves and the traffic. As the traffic turned onto final approach for the ILS it descended into some clouds. We immediately notified ATC that we lost visual and asked for a left 360 degree turn to help us with spacing. We were then given a left 180 degree turn and then shortly after another 180 degree turn. Upon being cleared back into the airport; ARTCC advised us to contact tower for possible pilot deviation. We complied and called on ground. Was advised they may or may not call me back.


Synopsis: HCF Controller and turboprop Captain reported possibly losing separation when a turbojet on approach overtook the turboprop and entered IMC. The turboprop aircraft was no longer able to maintain visual separation and requested a 360 turn for spacing.