Question: I was flying in Class E airspace and receiving radar service from air traffic control. The controller then instructed me to change my heading. The new heading was going to take me off of my intended course and I was in airspace that did not require me to be in contact with ATC. Did I need to comply with their instructions?
Answer: Yes. According to 14 CFR Part 91.123, pilots may not operate an aircraft contrary to ATC instructions in an area in which air traffic control is exercised. Pilots are not required to communicate with ATC in Class E airspace, but if a pilot chooses to be in contact with ATC, then the pilot must comply with the instructions that are given. A recent interpretation from the FAA Office of the Chief Counsel has brought clarity to this situation. As always, the pilot in command is the final authority as to the operation of the aircraft.