AA.I.D.K7FAA-S-ACS-11A · Nov 2023Knowledge
Maximum Lift over Drag Ratio (L/DMAX).
Maximum Lift over Drag Ratio (L/DMAX).
Bottom line
The maximum lift/drag ratio (L/DMAX) occurs at one specific coefficient of lift and angle of attack. If the aircraft is operated in steady flight at L/DMAX, the total drag is at a minimum. For a given aircraft configuration, L/DMAX occurs at a particular AOA and lift coefficient and is unaffected by weight or altitude.
Key numbers
| Number | What it means |
|---|---|
| one specific CL and AOA | L/DMAX AOA |
| at L/DMAX | Max range |
| at highest L/D | Best glide |
FAA references
- PHAK ch. 5 (p. 5-5) — FAA-H-8083-25C (2023)
- PHAK ch. 11 (p. 11-10) — FAA-H-8083-25C (2023)
- AFH ch. 3 (pp. 3-22–3-23) — FAA-H-8083-3C
- AFH ch. 5, Slow Flight (p. 5-10) — FAA-H-8083-3C
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