CA.I.D.K2FAA-S-ACS-7B · Nov 2023Knowledge
Altitude selection accounting for terrain and obstacles, glide distance of airplane, VF...
Altitude selection accounting for terrain and obstacles, glide distance of airplane, VFR cruising altitudes, and effect of wind.
Bottom line
The pilot must be sure that the aircraft is flying high enough to clear the highest terrain or obstruction along the intended route. To avoid terrain and obstacles, especially at night or in low visibility, determine safe altitudes in advance by using the altitudes shown on VFR and IFR charts during preflight planning.
Key numbers
| Number | What it means |
|---|---|
| More than 3,000 feet above the surface, in level cruising flight under VFR | VFR rule |
| Extra thousand feet or so of altitude from the leeward side of a mountain range | Leeward add |
FAA references
- PHAK ch. 8 (p. 8-6) — FAA-H-8083-25C (2023)
- PHAK ch. 2 (p. 2-9) — FAA-H-8083-25C (2023)
- 14 CFR 91.159 (VFR cruising altitude or flight level.) — eCFR current as of 2026-03-05
- AIM 7-6-7 (Mountain Flying) — AIM Basic 2/20/25 w/ Change 1 (8/7/25) & Change 2 (1/22/26)
- RMH ch. 3 (p. 3-7) — FAA-H-8083-2A
- AIM 3-1-5 (VFR Cruising Altitudes and Flight Levels) — AIM Basic 2/20/25 w/ Change 1 (8/7/25) & Change 2 (1/22/26)
- AFH ch. 18 (p. 18-4) — FAA-H-8083-3C
- AFH ch. 16 (p. 16-18) — FAA-H-8083-3C
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