Date: 201601
Local time of day: 1801-2400
Location: MKK.Airport, HI
Flight conditions: VMC
Light: Night
Aircraft: Medium Transport
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Initial Approach
Airspace: Class E ZHN
ATC / advisory: Center ZHN
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Anomaly: Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural FAR; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter CFTT / CFIT; Inflight Event / Encounter Unstabilized Approach
Detector: Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Company Policy
Primary problem: Company Policy

Narrative: During the enroute phase; I received a briefing on the approach and likely visual we would conduct using the MKK VOR approach. I was serving as FO and the PM.Being a night time; black hole visual and having done it hundreds of time before; it is always my desire to receive an extra briefing as to how the PF intends to negotiate the terrain when descending for the airport; VOR inbound; with the intention of a straight-in approach. Something that can be accomplished safely and within Standard Operating Procedures (SOPs); but requires experience and planning.When I asked the PF about this; he mentioned he would descend to 1;900 feet (600 feet above terrain) by the VOR and then descend from there and watch the radar altimeter to make sure we didn't get too close to terrain. I mentioned there were a few valleys and that this was not the safest and best idea. I instead mentioned the profile I adopted when I first started that provides for conservative terrain clearance no matter what the wind conditions; and aligns the aircraft with the runway at 500 feet with less than 1;000 FPM descent from this point forward. The PF expressed interest in this and ask me to repeat it as we went VOR inbound.As we began our visual approach with a clearance for the VOR-A approach; I became task saturated with radio calls and checklists. As we approached the VOR I realized the PF had begun a slow descent below 2;400 feet which is the minimum altitude for the VOR approach to 1;900 feet. I realized this as we approached the VOR and the PF began a descent again; at this time the radar altimeter was reading 600 feet. I verbalized I was not comfortable with this and they should stop the descent until we passed further from the VOR. The PF responded we're okay and pointed to the Radio Altimeter (RA). They then made a right turn towards the red light and of the 070 VOR course inbound from the VOR that is on top of the last ridge before the airport. This turn is towards more terrain. The PF continued his descent towards terrain to my horror and I carefully watched the RA which stayed around 600 feet. At this point; I was along for the ride having to rely on a Captain whose experience in an airplane and airport was extremely limited. They have a lot of experience flying all over the world so these action further surprised me.Two problems here:1) There is a common misconception among the majority of the pilots here that you can disregard minimum IFR altitudes when on an instrument approach clearance and outside the runway's circling radius.2) The methods; or lack thereof for no moon light; night time; VMC approaches to Runway 5.What the PF didn't seem to understand is that there are small valleys in this terrain and use of the Radar Altimeter (RA) should not be the primary aid in terrain clearance especially at 600 feet AGL. The RA provides no help when you're heading towards a mountain where one could easily end up being unable to out climb above rising terrain.I have total confidence in many of my fellow pilots and myself when flying into MKK. But whether you're a new pilot or a bigger risk taker; the level of confidence goes down drastically. I've even had a few other pilots express their discomfort and lack of confidence with flying into MKK at night. This raises a flag for me; help us help the company operate with the highest level of safety and efficiency.I have observed too many pilots taking [risks] at terrain separation with no visual reference to it and radar altimeters below 1;000 feet AGL. This is an unsafe practice. My wishes are not to prevent us from flying to MKK by any means. But we need to come up with a profile or profiles for guidance purposes because there are too many variations; many unsafe; that I find I have to guess at when I fly into MKK at night with no moon light. I really hope this will never be the case; but these practices are setting us up for an incident or worse someday.




Synopsis: A first officer reported unsafe practices for flying night-time approaches into MKK airport using the published MKK VOR Approach. The practice of using radar altimeter for terrain clearance at night reduced adequate altitude clearance above terrain of varying heights.