Then how do you explain this?
On Oct 1, 2021, at 10:51 AM, Taylor, Alex Q (FAA) <
[email protected]> wrote:
Good morning,
VLOS is defined in the reg as seeing the drone well enough to meet ALL of those criteria (LAADON) with unaided vision other than spectacles. If you don't meet all of LAADON criteria, you don't have VLOS, as far as the reg is concerned. 107.31 requires the RP to be able to have the ability to determine VLOS at all times during the flight, even if a VO is used and even if a VO is exercising the VLOS ability. As far as momentarily looking away, I suggest you read AC 107-2A, or the preamble to the final rule part 107. Both of those documents discuss "momentary" looking away as being an acceptable practice, but the documents also emphasize that the requirement for VLOS is not excused by looking away momentarily (to check telemetry, for example)
The VLOS requirement of 107.31 is required for both day and night operations, in all operating conditions. The 107.29 requirements are additional, and applicable for night. So if 107.31 applies at night, we can deduce that simply seeing an anti-collision light is not sufficient for meeting VLOS. The night visual illusions show why simply seeing the lights alone will not help determine LAADON, which is still required. It can be moving away from the pilot at a constant angle, for example, and the pilot won't know direction of flight or altitude in that example.
We know that visual acuity is much less at night, so we can also deduce from eye physiology that the distance one can determine LAADON is much less at night than it is during the day. The 3SM requirement for the anti-collision lighting is for the benefit of manned pilots to see the drone in time to maneuver away if needed, not for the drone pilot to use as the sole means of meeting VLOS at night.
I hope this helps you out.
Regards,
Alex Q. Taylor
Aviation Safety
Aviation Safety Technician
Springfield FSDO
1250 North Airport Drive, Suite 1
Springfield, IL 62707-8417
Office: (217) 744-1910
Desk: (217) 744-1913
Cell: (202) 642-5245