Date: 201501
Local time of day: 0601-1200
Location: HNL.Airport, HI
Flight conditions: VMC
Light: Daylight
Aircraft: Caravan 208B
Operator: Air Taxi
Operating under: Part 135
Flight plan: VFR
Mission: Passenger
Flight phase: Descent
Airspace: Class B HNL
ATC / advisory: TRACON HNL
Reporter organization: Air Taxi
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine
Human factors: Communication Breakdown; Confusion; Situational Awareness
Anomaly: ATC Issue All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural Clearance
Detector: Person Flight Crew; Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Separated Traffic; Air Traffic Control Issued Advisory / Alert; Flight Crew FLC complied w / Automation / Advisory; Flight Crew Requested ATC Assistance / Clarification
Contributing factors: Procedure
Primary problem: Procedure

Narrative: My captain and I were flying a part 135 flight to PHNL. Flying in Hawaii; and per 135.183; we're required to remain within gliding distance in our single-engine Cessna Caravan. The minimum altitude to cross the Molokai Channel is 5000 ft. MSL. The Caravan can glide roughly two miles per 1000 ft. of altitude; no wind. We had departed VFR and planned to do a visual approach into Honolulu. Upon switching to Honolulu Approach we requested the Freeway 2 arrival. The controller cleared us through the Bravo airspace and told us to turn to heading 230; descend and maintain 2000 ft. MSL. That heading brought us further off-shore; so we began a very slow descent down to 2000. After failing to receive a turn on-shore; we queried the controller about a turn inbound. The controller came on and said; 'If you don't increase your descent to 2000; I'm not going to be able to turn you in.' My captain got on the radio and informed the controller about our glide distance. The controller; in a much more agitated tone; told us once again that he could not turn us in unless we descended. My captain told him that we could not descend; reiterated our requirement to remain within glide; and requested a turn inbound. The controller; even more agitated; told us that he couldn't turn us unless we descended and informed us that we were in a departure corridor. When we asked what altitude we needed to be at before he could turn us; he told us that we needed to be below 4000 ft. MSL. We had to choose between descending slowly and going further outbound before turning on-shore or descending quickly; violating glide; and getting a quicker turn on-shore. In order to get into the airport; my captain complied with the controller's instructions. The request was a double-edge sword: either violate the controller's instructions or violate our glide requirement. I have been told that the approach control facility has been notified time and time again of our requirement to remain within glide; yet some controllers will not take that into consideration when issuing instructions.




Synopsis: A C208 flight crew inbound to PHNL requested a Freeway Visual approach but soon learned that the altitudes required for doing so overwater were incompatible with their requirement to remain within gliding distance of land when operating over water.