Small Transport
Air Traffic Control Fully Certified
Air Traffic Control Time Certified In Pos 1 (yrs) 3
Communication Breakdown; Confusion
ATC Issue All Types; Airspace Violation All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Human Factors; Environment - Non Weather Related; Procedure
Aircraft X was in level flight at 060 on V8 and instructed to depart MKK Vortac heading 195 for radar vectors to the GPS-B approach and would be number 2 to the airport following a small transport also inbound on the GPS-B approach.  Aircraft X acknowledged the clearance and in the meantime another aircraft was cleared out of MKK on the HAPAI2 departure to HNL via BAMBO climbing to 40 expecting higher en route.  When Aircraft X got about 10 miles NE of MKK she reported the field insight and then arbitrarily made a right 360 and started to descend.At this point the departure was about 10 miles north of MKK on the HAPAI2 and was now climbing to 050.  Once Aircraft X started her turn and descent the departure was less than 5 miles away; but still climbing out of 042 to 050.  Plus the MVA in that area is also 070.  The R-Side then advised Aircraft X that she was not cleared for the visual approach and she was descending below the MVA's in that area and to say intentions.  Then Aircraft X said they were climbing back up to 060 and going on the 195 heading as previously cleared.  Then the R-Side advised Aircraft X to continue climb to 070 for the MVA's and issued the MSAW alert.  Once level at 070 she was then vectored for the GPS-B approach and MKK Tower issued the Brasher Warning to Aircraft X.By the R-Side taking immediate action.  It prevented Aircraft X from being in real imminent danger.
This report is in response to HCF requiring PIC (me) to telephone them post flight because they thought I may have deviated from one of their people's instructions in flight. I assume they must be referring to this:Enroute to MKK on IFR flight plan.  I was asked by HCF what approach I wanted.  My SIC radioed back; per my command; GPS-B RWY 5.  I was advised by HCF to expect visual approach RWY 5.  Roger.  Leading up to this and during; radio congestion was very high.  Too high.  HCF demanded that those on frequency listen first before keying the mike.  Pilots were stepping on each others calls; blocking clear communication.Near MKK I spotted the field; radioed; 'Field in sight'. I heard; 'Number two to the field cleared visual.' I began a descent.  HCF radioed to me; 'I did not clear you for the visual.'  So I climbed back to my assigned altitude and heading as quickly as possible and responded 'correcting.'  HCF was concerned that I dropped below their MVA but quick enough I reached my previously assigned altitude and heading and they gave me a new series of vectors to the IAF to GPS B 5 MKK and cleared me for the approach.  We called field in sight again and confirmed cleared for the visual RWY 5.  We were switched over to Tower; cleared to land and did so without further concern. Overall I think this is the bracket of time where HCF must be focusing their concerns.MKK Ground relayed a message to me to call HCF.  I made the call. As of today; 27 hours after I called HCF; I have heard nothing further about this event but felt compelled to make this report anyway. If HCF thinks there was a deviation they're probably referring to that moment when I descended for the visual the first time.  Compounding radio congestion mixed with expectation bias played a big part in this event.  (I believe I was told to expect visual and indeed it is how I executed and terminated the approach/landing). If this situation arises again; I will probably cancel IFR; switch to Tower (different frequency); and just land the plane.
HCF Controller and aircraft pilot report of confusion related to approach clearance given/not given and MVA violation as a result of confusion.