AA.I.B.K4FAA-S-ACS-11A · Nov 2023Knowledge
Aerodynamics and how it relates to performance.
Aerodynamics and how it relates to performance.
Bottom line
Test data indicate that ice, snow, or frost formations having a thickness and surface roughness similar to medium or coarse sandpaper on the leading edge and upper surface of a wing can reduce wing lift by as much as 30 percent and increase drag by 40 percent. The aircraft's aerodynamic characteristics in high-altitude flight may differ significantly from those in lower altitude flight.
Key numbers
| Number | What it means |
|---|---|
| up to 30 percent | Lift loss |
| 40 percent | Drag increase |
| above 25,000 ft MSL | High-alt training |
FAA references
- AC 120-58 — AC 120-58
- AC 61-107, para. 1-7, 1-8 — AC No: 61-107B
- AC 61-138, para. 14.1.2.2 — AC No: 61-138A
- AC 91-74 Appendix 1 — AC No: 91-74A
- AC 135-17 — AC 135-17
- 14 CFR 91.103 (Preflight action.) — eCFR current as of 2026-03-05
- AC 20-117, para. 4g — AC No: 20-117
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