Date: 201201
Local time of day: 1201-1800
Location: FDK.Airport, MD
Flight conditions: VMC
Weather elements / visibility: 10
Light: Daylight
Aircraft: Cessna Super Skywagon/Super Skylane
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Personal
Flight phase: Takeoff / Launch
Airspace: Class D FDK
ATC / advisory: TRACON PCT
Second aircraft: Small Aircraft; Low Wing; 2 Eng; Retractable Gear
Reporter organization: Personal
Reporter function: Single Pilot
Reporter qualification: Flight Crew Instrument; Flight Crew Private
Human factors: Communication Breakdown; Situational Awareness
Anomaly: Conflict NMAC; Conflict Airborne Conflict
Detector: Person Flight Crew
When detected: In-flight
Result: General None Reported / Taken
Contributing factors: Human Factors
Primary problem: Human Factors

Narrative: I departed FDK today; under an IFR flight plan to return to my home airfield. I taxied to the hold-short area for Runway 23; double checked preparations; and then made a call to Potomac Clearance Delivery. I received my clearance: EMI; Radar Vectors to Belts; climb and maintain 3;000 FT; expect 4;000 FT 10 minutes after departure. Departure Frequency 125.52; Transponder Code XXYZ. The Controller asked that I advise him when ready for departure. I entered the flight plan; made final checks; and told the Controller I was ready to depart; but that there was several planes in the pattern at FDK and it might take a few minutes to depart while waiting on landing traffic. I remained at the Hold-Short line and I watched and heard the radio call of a single engine Cessna do a low approach and go-around. I then watched a second aircraft; a larger single engine vintage yellow plane with 'Navy' on the side of the fuselage; land. I waited until that aircraft cleared Runway 23. I then announced on the UNICOM that I was taking the active Runway 23 for departure. I heard no aircraft announce they were on final. I did observe that the Cessna that had done a go-around was now abeam the numbers but still on the downwind leg of the pattern for Runway 23. I looked for landing traffic; saw none; and heard none. I entered the runway and proceeded with a normal takeoff. Several hundred feet down the runway; just the plane was becoming airborne; I looked up and saw the underside of a large twin aircraft. I estimate it was about 400-500 above me; slightly off to the left side of me and the runway and it was turning left away from the runway. I was already airborne and proceeded straight out to continue to open the distance between me and the twin. I quickly lost sight of the twin. I contacted Potomac Approach on the assigned Departure Frequency; turned towards EMI; and was subsequently vectored without incident. After turning towards EMI; I looked again for the twin or other traffic and saw none. If I inadvertently shifted to the wrong frequency; such as Clearance Delivery; then I never heard Potomac announce that I was on their frequency when I made the announcement of entering Runway 23 for departure.




Synopsis: C205 pilot reports a conflict with a light twin while taking off from Runway 23 at FDK. The reporter did not hear the light twin self announcing nor did he see it as he checked final taking the runway.