Date: 201211
Local time of day: 0001-0600
Location: SDF.Airport, KY
Flight conditions: VMC
Light: Daylight
Aircraft: B737-700
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Flight phase: Initial Climb
Airspace: Class C SDF
ATC / advisory: Tower SDF
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Human factors: Confusion; Communication Breakdown
Second reporter function: Pilot Flying; First Officer
Anomaly: ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Air Traffic Control
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented
Contributing factors: Procedure; Human Factors
Primary problem: Human Factors

Narrative: The SDF Tower Controller cleared me for takeoff on Runway 17R and said to RNAV TAYVL. We were departing on the FEDRA ONE RNAV Departure and I read back; 'Cleared for takeoff direct TAYVL.' I selected and executed TAYVL while the First Officer selected LNAV on the MCP. Departure Control told us to turn to a heading of 180; traffic off the left; and we were to be on the FEDRA ONE Departure. We turned to the heading and I told ATC that I thought we were instructed to proceed direct to TAYVL. I am still confused as to why the instruction is not FEDRA ONE RNAV Departure TAYVL if they want you to stay on the departure. I really thought the instruction was to RNAV to TAYVL; miscommunication with ATC.


Second narrative: We were cleared to line up and wait on Runway 17R. Captain transferred aircraft control to me (the pilot flying). We were cleared for takeoff and I understood the clearance to fly the RNAV departure we had briefed; loaded; and verified. I selected LNAV prior to takeoff and announced my selection. The takeoff sequence was normal and we were on profile. I noticed that the command bars were directing me to turn to the left although I thought we were to continue on the 168 degree heading per the FEDRA1 Departure. I was confused because in my mind I believed we were to fly further away from the runway before turning towards TAYVL. I looked at the departure page quickly and tried to find my misunderstanding and verify what the correct lateral path was. There is no DME information prior to turning east toward TAYVL. I recall thinking that it must be an altitude that we obtain and perhaps that dictated a turn to the east. We were above 3;000 FT AGL and I was near VFS still. My attention was diverted further because I was still handing flying the aircraft at this point. I asked the Captain why the command bars were commanding a left turn so quickly once I could not figure it out for myself. I said that it did not make sense to me as I thought we were to fly further south than we had. The Captain responded that we were cleared direct TAYVL and that was what the Captain had selected. I did not see the Captain line select direct but once I was informed we were cleared direct via ATC by the Captain; I initiated the turn toward TAYVL. I thought that while I was hand flying and trying to figure out the correct lateral path that I missed a radio transmission from ATC clearing us direct to TAYVL. Again; my focus was on flying the aircraft and attempting to solve the discrepancy presently. The coordination between us was a factor as well as the clearance as it was understood from SDF Tower Controller. Rather quickly; we were told to fly a heading of 170 and then 180. I complied and turned immediately. When we were told to do so I realized that something was wrong. I should have placed the aircraft on autopilot sooner. It would have 'freed' me from having to hand fly and correct a navigation and communication issue. I should have asked the Captain to verify with ATC immediately when the initial doubt about our lateral path came into question. I didn't hear 'cleared direct' but simply accepted that was the clearance given after I queried the Captain. The Captain was sure of the direct clearance so I complied. But; I should have asked the Captain to verify that because my attention was on hand flying and in being confused as to why the flight director was commanding an easterly turn. I should have backed up the Captain in that respect and should have been more assertive and helpful. The clearance from SDF Tower may have been non-standard in delivery. We were informed that SDF is encountering many of these types of deviations. Perhaps clearer verbiage would be advantageous.


Synopsis: Air Carrier departure from SDF failed to comply with ATC instructions partly due to miscommunication in the cockpit and the ATC instructions.