CA.I.C.K3lFAA-S-ACS-7B · Nov 2023Knowledge
l. Obstructions to visibility (e.g., smoke, haze, volcanic ash, etc.)
Meteorology applicable to the departure, en route, alternate, and destination under visual flight rules (VFR) in Visual Meteorological Conditions (VMC), including expected climate and hazardous conditions such as: l. Obstructions to visibility (e.g., smoke, haze, volcanic ash, etc.)
Bottom line
If no visible horizon can be seen due to clouds, whiteouts, haze over the ocean, night over a dark ocean, etc., it is IMC for practical and safety purposes.
Key numbers
| Number | What it means |
|---|---|
| 15 to 20 minutes old by the time the mosaic data sets are assembled and displayed in a cockpit | NEXRAD age |
| first 12 hours of the forecast period | SIGWX ash window |
| significant changes expected within 1 hour before and after the ETA | Destination forecast |
FAA references
- PHAK ch. 13 (p. 13-7) — FAA-H-8083-25C (2023)
- AFH ch. 3 (p. 3-4) — FAA-H-8083-3C
- AC 91-92, paras. 4.17, 7.6, 7.7 — AC No: 91-92
- AWH ch. 3 (p. 3-25) — FAA-H-8083-28A
- AC 91-92 Appendix A — AC No: 91-92
- RMH ch. 3 (p. 3-8) — FAA-H-8083-2A
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