You are departing a Class D airport and are receiving VFR flight following. After you are handed off to the nearest tracon and establishing communication, the controller issues a vector for traffic and provides you with a heading and altitude. You acknowledge the vector, but quickly realize that continuing at this heading and altitude will put your aircraft into Class B airspace. However, the frequency becomes so congested that you can't communicate with the controller, and the Class B airspace is rapidly approaching.
Is the vector for traffic with the heading and altitude assignment a clearance for you to enter Class B airspace? Consider 14 CFR 91.131: Operations in Class B airspace. This regulation provides that “no person may operate an aircraft within a Class B airspace area except in compliance with 14 CFR 91.129,” and “the operator must receive an ATC clearance from the ATC facility having jurisdiction for that area before operating an aircraft in that area.”
In this case there is no clearance to enter Class B airspace, because you must specifically receive an ATC clearance to enter the Class B airspace. The vector you received is not a clearance to enter the Class B airspace. The FAA has specifically stated that the “issuance of a vector provides navigation information but does not provide clearance from ATC to enter the subject airspace.”
So, if you are not cleared to enter the Class B airspace and cannot obtain a clearance due to a congested frequency, would turning to avoid the Class B airspace constitute a FAR violation? This time, the most relevant regulation is 14 CFR 91.123: Compliance with ATC clearances and instructions, which provides, in part, that no pilot in command may deviate from an ATC clearance “unless an amended clearance is obtained, an emergency exists, or the deviation is in response to a traffic alert and collision avoidance system resolution advisory.”
According to the FAA, turning to avoid the Class B airspace is not a violation because “the pilot only received the vector for traffic from ATC, the pilot did not receive a clearance or instruction from ATC. Therefore, any maneuvering by the pilot is not a violation of FAR 91.123.”
However, the FAA has cautioned, “in maneuvering the aircraft, the pilot must comply with FAR 91.111: Operating near other aircraft and not operate the aircraft so close to another aircraft as to create a collision hazard.”
The above hypothetical and questions were presented to the FAA’s Office of Chief Counsel for legal interpretation in the Doremire Letter (Jan. 14, 2010). Read the complete letter of interpretation here.