First-person-view goggles do not satisfy §107.31. That section requires the remote pilot in command, the visual observer if one is used, and the person manipulating the controls to be able to see the unmanned aircraft throughout the flight with vision unaided by any device other than corrective lenses. AC 107-2A paragraph 5.9.1 says first-person-view devices may be used and still do not satisfy visual line of sight.
The rule
The four purposes of that sight are in §107.31(a): know the aircraft's location; determine its attitude, altitude, and direction of flight; observe the airspace for other traffic or hazards; and determine that the aircraft does not endanger life or property. A video picture can help you frame a shot. It is not one of those four acts performed with your eyes on the aircraft.
Section 107.31(b) lets the ability to see the aircraft be exercised by the remote pilot and the person on the controls, or by a visual observer. Section 107.31(a) still requires the remote pilot and the person manipulating the controls to be able to see the aircraft throughout the flight. AC 107-2A paragraph 5.9.2 states that capability even when an observer is used. Staying below 400 feet does not remove it. A controller screen watched by the observer does not satisfy it either.
Corrective lenses are the one aid the rule names. Prescription glasses and contact lenses count. Binoculars do not. Section 107.31 requires vision unaided by any device other than corrective lenses, so binoculars cannot be the primary or continuous means of maintaining visual line of sight. FAA guidance allows only brief scanning use. Handing the pilot binoculars so a shrinking aircraft stays "in view" for the rest of the inspection fails the rule. An assistant who then watches the controller adds nothing, because a camera view is not visual line of sight.
A true beyond-visual-line-of-sight flight needs a waiver of §107.31. How that waiver is requested is on waivers and authorizations. The observer's own duties, when you choose to use one, are on the visual observer page.
How to apply it
If the shot needs the goggles, put an observer where that person can see the aircraft with unaided vision, and keep a way for you to see it too. Lifting the goggles is the example the test uses. Brief the observer under §107.33 so communication, the scan, and awareness of position are real. Flying the entire shot alone in the goggles, with no waiver, leaves nobody exercising visual line of sight with their eyes.
Treat momentary occlusion as a capability problem, not as a timer. AC 107-2A paragraph 5.9 says the person maintaining visual line of sight may have brief moments of not looking at or not seeing the aircraft if that person still retains the capability to see it or can quickly maneuver it back to visual line of sight, and must regain visual line of sight as soon as practicable. No fixed time interval is authorized. The aircraft passing behind a large tree for about two seconds, then reappearing when the pilot sees it again immediately, can fit that guidance when the crew retains the capability to see it or maneuvers it back as soon as practicable. The controller screen during those two seconds is not what makes the moment legal.
The opposite case is the aircraft that has become too small to see. Binoculars held up for the rest of the line inspection do not restore §107.31. Bring the aircraft back to a distance where unaided vision works, or stop.
A cinematic orbit and a transmission line
You are alone and you want the goggles down for the whole orbit. No waiver is on the aircraft. That operation is not legal merely because the goggles show a continuous picture, and it is not legal if a friend watches the controller. It can be conducted with a visual observer who keeps unaided visual contact with the aircraft while you remain able to see it, for example by lifting the goggles.
Later the aircraft slips behind a tree for about two seconds. You still know where it is, you can pitch it back into view, and you do that as soon as practicable. You do not keep flying the hidden arc on the screen. The visual line of sight page is the home for the four purposes. This page is the goggle, the tree, and the binoculars.
On the transmission-line job the aircraft is getting hard to see. An assistant offers binoculars for the rest of the flight, and offers to watch the screen. Both offers leave the operation noncompliant. Brief scanning with binoculars is the limited use the guidance allows. Continuous use as the means of line of sight is the failure.
The trap
The goggle item says the camera view is already legal, or that the observer may watch the screen. Paragraph 5.9.1 rejects the devices as visual line of sight. The legal pattern is the observer on the aircraft and the pilot still able to see it.
The tree item's wrong answer says any period when no one can see the aircraft, however brief, fails §107.31 and that FAA guidance states no exception. The section is a capability standard, and paragraph 5.9 is the brief-moment guidance. The other wrong answer credits the controller screen. No fixed number of seconds is printed in the rule. A planned disappearance down the line is a different flight from a two-second occlusion you immediately undo.
The binocular item equates binoculars with glasses, or adds a screen-watching assistant. Glasses are the allowed device. Binoculars are not the means of maintaining the line of sight.
Run these three on the free practice test. The course pairs the goggle setup with the observer rules so the waiver is reserved for a flight that truly leaves visual line of sight.