CA.I.C.K3kFAA-S-ACS-7B · Nov 2023Knowledge
k. Frost
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: k. Frost
Bottom line
Frost is the formation of thin ice crystals on the ground or other surfaces on solid objects below the freezing point of water. Frost disrupts the flow of air over the wing and can drastically reduce the production of lift.
Key numbers
| Number | What it means |
|---|---|
| 110 knots — Type II and IV fluids are not appropriate for aircraft rotating below this speed | Fluid rotation speed |
| 0 degrees C (32 degrees F) — at or below, for frost formation from water vapor | Frost surface temp |
FAA references
- PHAK ch. 12 (p. 12-15) — FAA-H-8083-25C (2023)
- AC 91-74, para. 7-1 — AC No: 91-74A
- AC 135-17 — AC 135-17
- AWH ch. 21 (p. 21-5) — FAA-H-8083-28A
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