Date: 201508
Local time of day: 0601-1200
Location: OTH.Airport, OR
Flight conditions: VMC
Weather elements / visibility: Haze / Smoke; 6
Light: Daylight
Aircraft: Small Aircraft; Low Wing; 1 Eng; Fixed Gear
Operator: Personal
Operating under: Part 91
Flight plan: None
Mission: Personal
Flight phase: Final Approach
Airspace: Class D OTH
ATC / advisory: Tower OTH
Second aircraft: Helicopter
Reporter organization: Personal
Reporter function: Pilot Flying; Single Pilot
Reporter qualification: Flight Crew Instrument; Flight Crew Private
Human factors: Communication Breakdown; Confusion; Workload; Distraction; Situational Awareness
Anomaly: ATC Issue All Types; Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued Advisory / Alert; Flight Crew Became Reoriented; Flight Crew Took Evasive Action
Contributing factors: Human Factors; Environment - Non Weather Related; Procedure
Primary problem: Procedure

Narrative: I was descending from the NE at about 15 nm and 6;500 feet and contacted the OTH tower on 118.45 requesting a flyby. The tower responded acknowledging the call sign and asked at what altitude. I asked what altitude would work and the tower asked that is requested so I indicated 500 feet. The tower said to report 2 miles. The tower as I got closer to the airport asked if a Cessna was in sight that was making an approach to landing at the airport. I responded that the Cessna was in sight and would make a 360 to stay out of the Cessna's way. After rolling out near the RWY 22 heading; I was going to communicate nearing 2 miles however the tower was on frequency with another aircraft. By the time I was able to communicate with the tower; it was approaching RWY 22. The altitude was estimated to be at or near pattern altitude and well above the 500 feet requested. At the time of the approach; a Helicopter was given clearance to takeoff by the tower. The Helicopter had me in sight and altered it's normal takeoff procedure to ensure there was no conflict with me. Once realizing that the Tower was upset that I overflew his runway without a clearance to do so; I executed a right 160 degree turn and proceeded up the coast and out of the Tower's Class D airspace.The issue I believe arose as the Tower thought that I was requesting permission to transit the area. I assumed the Tower knew that a flyby down (low approach) was requested when the tower asked me to report 2 miles and I had requested 500 feet. It's hard to imagine that the Tower would think that I would want to transit the area at 500 feet. The miss-communication I believe was on both ends. I should have utilized the correct terminology with an airport potentially unfamiliar with overhead passes. I should have executed a maneuver to avoid overflight of the airport as clearance to make an approach was not received. The Tower should have questioned the intention of me if it really thought I wanted to transit the area at 500 feet. In addition; the tower had sight of me performing the right 360 and in fact confirmed this with me after the tower had pointed out my position in a turn to another aircraft. The Tower also added during the commentary to the other aircraft that I was turning in fog bank. The Tower's perception must have been off as I was well clear of the fog off of the coast by at least an estimated 2 miles. I thought that this was an odd comment by the Tower to state this without really knowing but I did not respond to this commentary by the tower.Bottom line is that the lack of good communication between myself and the tower led to what could have been a serious situation as another aircraft had been cleared to take off. It also lured me into a situation that could probably have been avoided since communication at a critical juncture (2 miles) was unable to be made. Since I remained higher than requested and most likely above or close to pattern altitude; the threat of possible mid-air was probably not that high but should have been avoided just the same.




Synopsis: A pilot requested a low pass over OTH Runway 22; but after the maneuver ATC was upset because the 500 FT altitude was understood to be a transit request through Class D; not a low pass over traffic.