Skyhawk 172/Cutlass 172
Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 10; Flight Crew Total 700; Flight Crew Type 660
Workload; Situational Awareness; Distraction; Confusion
Conflict Airborne Conflict; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem; Flight Crew Returned To Clearance; Flight Crew Became Reoriented
Human Factors; Weather; Procedure
On departure; the initial climb was pretty smooth; but winds were from the southwest with gusts to 20 knots. I started my turn to the north at about 400 feet AGL; and about then was hit with a burst of turbulence that really rocked the plane. The TAWS unit called out 'Obstacle'; then 'Sink Rate; Pull Up'. While recovering from this and re-establishing the climb; I continued my turn through the assigned 350 degree heading to about 60 degrees; toward the incoming aircraft on approach.During the turbulence; I had tried to flip-flop the radio from tower to departure; but the bumpy ride made me brush my finger against the wrong part of the GTN 650 touch screen; leaving the COM radio on the wrong frequency. While turning; I was re-tuning the radio; and when I got it to the correct frequency I immediately heard the departure controller instructing me to turn back to the 350 degree heading. I turned and climbed and followed the rest of the departure instructions correctly. I was instructed to call ATC on landing; since there was a possible loss of separation.Partly due to the turbulence and recovery; and partly due to confusion; once I had continued the turn to far toward the east; I misinterpreted the CDI guidance and would have continued the turn. I had turned the ZZZ VOR into the NAV2 radio; which meant that the needle was 'reverse sensing'. Following the needle at this point was leading me the wrong direction.I could have avoided some of the confusion if I had programmed the GTN 650 better. I had set it into OBS mode with the 286 radial off of ZZZ VOR; so that it was showing the same guidance as the NAV2 radio. If I had entered it as ZZZ VOR to ZZZZZ Intersection; then the map representation would have been more helpful.Before takeoff; I had briefed the departure; but had not actually pulled up the enroute chart and drawn in the route; which I would have normally done if it were IMC. I had a casual attitude about the departure procedure; thinking of it as an obstacle departure procedure that wasn't that important since it was VMC. In reality; it's more like a SID; to keep aircraft away from the approach path; but without the graphical representation. When I spoke with the departure controller; he said that they had a lot of problems with pilots not following the Departure Procedure. Perhaps this would be improved if it were published as a SID.
A C172 pilot reported becoming confused and disoriented after takeoff; due to a sudden and unexpected turbulence encounter. The resulting heading and altitude deviation generated both an obstacle and sink rate warning.