PA.XI.A.K5FAA-S-ACS-6C · Nov 2023Knowledge
Night orientation, navigation, chart reading techniques and methods for maintaining nig...
Night orientation, navigation, chart reading techniques and methods for maintaining night vision effectiveness.
Bottom line
The rods can take approximately 30 minutes to fully adapt to darkness, and a bright light can completely destroy night adaptation. Without supplemental oxygen, an individual's night vision declines measurably at pressure altitudes above 4,000 feet. Off-center viewing requires looking 10° above, below, or to either side of an object so peripheral vision can maintain contact with it.
Key numbers
| Number | What it means |
|---|---|
| ~30 minutes for rods to fully adapt | Dark adapt |
| Above 4,000 feet pressure altitude without supplemental oxygen | Vision loss |
| Above 5,000 feet cabin pressure altitude | Adapt impaired |
| 10° above, below, or to either side | Off-center |
| No longer than 2 to 3 seconds each | Scan stops |
FAA references
- PHAK ch. 17 (p. 17-23) — FAA-H-8083-25C (2023)
- PHAK ch. 17 (pp. 17-24–17-25) — FAA-H-8083-25C (2023)
- AIM 8-1-6 (Vision in Flight) — AIM Basic 2/20/25 w/ Change 1 (8/7/25) & Change 2 (1/22/26)
- RMH ch. 6 (p. 6-2) — FAA-H-8083-2A
- AFH ch. 5, Human Factors (p. 5-3) — FAA-H-8083-3C
- AIM 5-4-24 (Charted Visual Flight Procedure (CVFP)) — AIM Basic 2/20/25 w/ Change 1 (8/7/25) & Change 2 (1/22/26)
- RMH ch. 3 (p. 3-4) — FAA-H-8083-2A
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