PA.IV.E.K1FAA-S-ACS-6C · Nov 2023Knowledge
Effects of atmospheric conditions, including wind, on takeoff and climb performance.
Effects of atmospheric conditions, including wind, on takeoff and climb performance.
Bottom line
High density altitude reduces aircraft performance: it reduces normal horsepower output and propeller efficiency, increases runway length requirements for takeoffs and landings, and decreases rate of climb. A heavier gross weight results in a longer takeoff run and shallower climb.
Key numbers
| Number | What it means |
|---|---|
| 70 percent of lift-off airspeed by runway midpoint, or abort | Halfway check |
| broadcast at airports 2,000 feet elevation and higher when temperature reaches a predetermined level | DA advisory |
| 1,500 to 2,000 feet per minute on the leeward side of mountain passes | Leeward downdrafts |
FAA references
- AIM 7-6-7 (Mountain Flying) — AIM Basic 2/20/25 w/ Change 1 (8/7/25) & Change 2 (1/22/26)
- PHAK ch. 5 (p. 5-42) — FAA-H-8083-25C (2023)
- AIM 7-6-8 (Use of Runway Half-way Signs at Unimproved Airports) — AIM Basic 2/20/25 w/ Change 1 (8/7/25) & Change 2 (1/22/26)
- PHAK ch. 11 (p. 11-5) — FAA-H-8083-25C (2023)
- AFH ch. 9 (p. 9-12) — FAA-H-8083-3C
- RMH ch. 3 (p. 3-7) — FAA-H-8083-2A
- RMH ch. 3 (p. 3-6) — FAA-H-8083-2A
Build understanding you can use
Unlock the full lesson and continue studying this element.
- Full teaching sections: What it is; Key points; Rules and numbers; How it is done
- Check your understanding with answers you can reveal
- Common mistakes paired with the FAA facts that correct them