AI.XIII.C.K5bFAA-S-ACS-25 · Nov 2023Knowledge

b. Wing flaps extended

ACS element text (the applicant demonstrates understanding of)

Effects on performance of various configurations including: b. Wing flaps extended

Bottom line

When extended, flaps move simultaneously downward to increase the lifting force of the wing for takeoffs and landings. VFE is the highest speed permissible with the wing flaps in a prescribed extended position, because of the air loads imposed on the structure of the flaps.

Key numbers

Key numbers for b. Wing flaps extended
NumberWhat it means
VFE — highest speed permissible with flaps in a prescribed extended positionFlap speed
Do not pass VNE, VLE, or VFE, as applicableEmergency descent

FAA references

  1. PHAK ch. 3 (p. 3-5) — FAA-H-8083-25C (2023)
  2. PHAK ch. 11 (p. 11-19) — FAA-H-8083-25C (2023)
  3. AFH ch. 18 (p. 18-9) — FAA-H-8083-3C
  4. AFH ch. 12, Operational Procedures (pp. 12-4–12-5) — FAA-H-8083-3C
  5. PHAK ch. 5 (p. 5-50) — FAA-H-8083-25C (2023)
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