Definition
A note published on an instrument approach chart indicating that the standard helicopter visibility reduction is Not Authorized for that procedure. Normally, under 14 CFR Part 97, helicopters may use one-half the published Category A landing visibility minimum (down to a floor of 1/4 statute mile or 1200 RVR). When the chart carries the 'Visibility Reduction by Helicopters NA' notation, this allowance does not apply, and the helicopter must use the published Category A visibility minimum as charted.
Plain English
It is a note on an approach chart telling helicopter pilots they cannot use the usual rule that lets them fly the approach with half the published visibility. On this approach, helicopters must meet the same visibility minimum shown for small airplanes.
Context Anchor
Seen in the notes on an instrument approach chart, especially when a helicopter pilot is checking whether helicopter visibility reduction is allowed for that procedure.
Derivation
NA is FAA chart shorthand for “Not Authorized.” In this note, it means the visibility-reduction allowance is not permitted on that approach.
Why Pilots Care
Loss of visual references can lead to spatial disorientation, controlled flight into terrain, or aborted approaches; procedures must account for this risk at unprepared or contaminated landing zones.
Grounding Statement
When this note appears, treat the printed visibility minimum as fixed for helicopters.
Intuition Check
Do not read NA as “not applicable” here. It means “not authorized,” so the reduction is prohibited. Do not assume helicopters always get to use a lower visibility number. This note says they do not on this procedure.
Example Sentence 1
Briefing the approach, the pilot noted 'Visibility Reduction by Helicopters NA' and planned to use the full 3/4 SM Category A minimum rather than 3/8 SM.
Example Sentence 2
During the approach briefing the crew noted that visibility reduction by helicopters could occur if the snow-covered pad was disturbed.