Sustained flight over an open-air assembly is allowed for Category 1, Category 2, and Category 4 only when that operation meets §89.110 or §89.115(a). Category 3 may not operate over an open-air assembly at all under §107.125(b). Sections 107.110(b), 107.115(b), and 107.140(a)(2) are the Remote ID conditions for the three categories that can make that flight.
The rule
Sustained flight over an assembly includes hovering above it, flying back and forth over it, or circling over any part of it. Circling one end of a packed stadium crowd to hold a camera angle is sustained flight, and it is flight related to the event. The exception is narrower than "a short pass." It is a brief, one-time transit over part of the assembly when that crossing is only incidental to a point-to-point flight unrelated to the assembly. Moving between camera positions to film the same crowd is related to the event, so it is not the exception. Hovering over an empty lot is not flight over the assembly. Flying parallel to the crowd along a boundary, without crossing over anyone, is not flight over the assembly either.
Remote ID in this sentence means the operation meets §89.110 or §89.115(a). Section 89.110 is a standard remote identification unmanned aircraft broadcasting the message elements in §89.305. Section 89.115(a) is a remote identification broadcast module. The assembly paragraphs do not name the FRIA path in §89.115(b). A crowd that has been told a drone might fly overhead is not a substitute. The Remote ID page keeps the three Part 89 paths separate from Subpart D.
Category 1 still has to be Category 1: 0.55 pounds or less throughout the flight, including everything attached, and no exposed rotating parts that would lacerate skin. That weight does not waive §107.110(b). Category 2 still has to be listed, labeled, and eligible. Category 4 still has to meet the airworthiness and Flight Manual rules. The category you are in is decided first. The assembly condition is added on top for Categories 1, 2, and 4, and it is a hard stop for Category 3.
How to apply it
Draw the flight path on a diagram of the crowd before you call the shot legal. If the path hovers, circles, or shuttles over any part of the gathering, treat it as sustained flight and ask two questions. Is the aircraft in Category 1, 2, or 4, with every condition of that category met? Does this operation meet §89.110 or §89.115(a)? If either answer fails, do not hold that path. A Category 3 aircraft does not get a third question. Section 107.125(b) says the remote pilot must not operate it over an open-air assembly. Remote ID does not open that door. A parade is one of the gatherings the rule treats as an open-air assembly, which the Category 3 page covers from the closed-site side.
A transit that qualifies is a flight whose purpose is somewhere else. A survey heading from one job site to another may cross the edge of a parade once, without hovering, returning, or filming the parade. That crossing is unrelated to the assembly. If the purpose of the pass is the parade, the game, or the festival, the flight is related to the event and the exception does not apply. A second pass to fix a frame is the same problem. Flying the boundary road with the aircraft offset so it never goes over a person is a different operation from flight over the assembly, and §107.39 still applies the moment the aircraft is over a person who is not participating or sheltered.
A stadium end zone
The assignment is a packed stadium. You have a Category 1 aircraft at 249 grams with shrouded propellers, no Remote ID broadcast, and you are not using a broadcast module. Orbiting the end zone to hold the angle is sustained flight over the assembly. Section 107.110(b) prohibits that operation unless it meets §89.110 or §89.115(a). Visual line of sight does not replace the broadcast. The aircraft's weight and the shrouds do not replace it. Telling the crowd, or getting a nod from the organizer, does not replace it.
Moving that same aircraft from the north lot to the south lot so the camera can cover the game is still a flight related to the event. A short hop between those lots is not the unrelated transit. The moment the pilot circles the end zone, the flight is sustained as well. A Category 4 aircraft with a legal Flight Manual faces the same Remote ID condition for a sustained orbit. A Category 3 aircraft cannot take the orbit at all. An unrelated example is a mapping flight whose route happens to cross the stadium's edge once on the way to a site that has nothing to do with the game, with no return and no camera on the crowd.
The trap
The multiple-choice trap offers all four categories "if Remote ID compliant," and it offers Categories 2 and 4 only, as if Category 1 were too light to need a condition. The correct set is Categories 1, 2, and 4, and only when the aircraft operation meets the Remote ID requirement in §89.110 or §89.115(a). Category 3 stays out. Organizer permission is not the condition. Category 1's weight limit is not a waiver of Remote ID for an assembly.
The sustained-flight trap treats every pass as identical. Circling the end zone is sustained, and a hop between filming positions for that game is related to the event. A brief point-to-point crossing counts as transit only when the flight is unrelated to the assembly. A track that stays beside the crowd without going over anyone is not flight over the assembly. The Category 1 item then tries the closed-site notice sentence, which is a Category 3 tool for people who are not an open-air assembly. Category 3 is forbidden over open-air assemblies entirely, so that notice cannot legalize a Category 1 orbit that has no standard Remote ID and no broadcast module.
Sort a few assembly paths on the free practice test. The course pairs each category's assembly sentence with the sustained-flight examples the test uses.