We agree that, for purposes of section 61.57(b), an authorized instructor providing instruction in an aircraft is not considered a passenger with respect to the person receiving instruction, even where the person receiving the instruction is acting as PIC. (The instructor must be current, qualified to instruct, and hold a category, class and type rating in the aircraft, if a class and type rating is required.) The instructor is not a passenger because he is present specifically to train the person receiving instruction. Neither is the person receiving instruction a passenger with respect to the instructor. This training may take place, even though neither pilot has met the 61.57(b) requirements.
That paragraph, quoted from the previously named night currency thread (legal interpretation contained therein) makes a fairly clear statement regarding the relationship of the student and instructor in the airplane.
Several posters have tried to expand on this concept by including flight attendants and passengers on an airliner, however, the legal interpretation goes on to state that this concept applies ONLY to the instructor-student relationship. Therefore, attempting to enlarge the view by adding examples outside a cockpit instruction scenario has no relevancy.
Further, while the specific question cited in that legal interpretation, the question which spurred the authoring of that interpretation involves an instructor and a rated pilot certificate holder, we may infer that it applies beyond the only flying with a private pilot and instructor because of the use of the word "even." We find that word in the first sentence, showing that the instructor would not be a passenger with or without the student holding a pilot certificate. Likewise, the student is not a passenger.
I believe there's some confusion here becuase an assumption is being made in this thread that one is either a required crewmember, or a passenger. This is not necessarily the case...any more than one must be either PIC or SIC in the cockpit. A student is neither...we even have a category for logging flight time (a separate issue) which involves "dual" or instruction received...it's not PIC, nor is it SIC. Can a student be neither a required crewmember, nor a passenger? This would appear so.
Perhaps one should look closely at the purpose of the flight. The purpose is flight instruction. If the purpose were otherwise, such as flying to another location to drop off a case of beer, the reationship and the definition might change, even though instruction might take place during the flight. Much of the regulation regarding PIC issues is closely tied to additional consideration, such as purpose...this spills over into other regulations we frequently address as well, such as quasi-135 type issues.
Were the instructor on board to pilot the airplane to another location to drop the student in order to visit his sick poodle Millie, at the vets, perhaps the student might become passenger rather than student. Whereas the purpose of the flight is instruction, and the student-instructor relationship has been presumed to exist for the purposes of this discussion, might we contemplate an additional aspect of one's standing on board beyond required crewmember, and passenger?
The interpretation certainly would make it appear so.