---
kind: "section"
citation: "14 C.F.R. § 25.479"
title: "14"
number: "25.479"
heading: "Level landing conditions."
url: "https://uscodex.org/cfr/14/25.479"
---

# §25.479. Level landing conditions.

- (a) In the level attitude, the airplane is assumed to contact the ground at forward velocity components, ranging from VL1 to 1.25 VL2 parallel to the ground under the conditions prescribed in [§ 25.473](/cfr/14/25.473.md) with—
  - (1) VL1 equal to VS0 (TAS) at the appropriate landing weight and in standard sea level conditions; and
  - (2) VL2 equal to VS0 (TAS) at the appropriate landing weight and altitudes in a hot day temperature of 41 degrees F. above standard.
  - (3) The effects of increased contact speed must be investigated if approval of downwind landings exceeding 10 knots is requested.
- (b) For the level landing attitude for airplanes with tail wheels, the conditions specified in this section must be investigated with the airplane horizontal reference line horizontal in accordance with Figure 2 of Appendix A of this part.
- (c) For the level landing attitude for airplanes with nose wheels, shown in Figure 2 of Appendix A of this part, the conditions specified in this section must be investigated assuming the following attitudes:
  - (1) An attitude in which the main wheels are assumed to contact the ground with the nose wheel just clear of the ground; and
  - (2) If reasonably attainable at the specified descent and forward velocities, an attitude in which the nose and main wheels are assumed to contact the ground simultaneously.
- (d) In addition to the loading conditions prescribed in [paragraph (a)](#a) of this section, but with maximum vertical ground reactions calculated from [paragraph (a)](#a), the following apply:
  - (1) The landing gear and directly affected attaching structure must be designed for the maximum vertical ground reaction combined with an aft acting drag component of not less than 25% of this maximum vertical ground reaction.
  - (2) The most severe combination of loads that are likely to arise during a lateral drift landing must be taken into account. In absence of a more rational analysis of this condition, the following must be investigated:
    - (i) A vertical load equal to 75% of the maximum ground reaction of [§ 25.473](/cfr/14/25.473.md) must be considered in combination with a drag and side load of 40% and 25% respectively of that vertical load.
    - (ii) The shock absorber and tire deflections must be assumed to be 75% of the deflection corresponding to the maximum ground reaction of [§ 25.473(a)(2)](/cfr/14/25.473.md?p=a-2). This load case need not be considered in combination with flat tires.
  - (3) The combination of vertical and drag components is considered to be acting at the wheel axle centerline.

## Notes

### Amendments

[Amdt. 25-91, 62 FR 40705, July 29, 1997; Amdt. 25-91, 62 FR 45481, Aug. 27, 1997]

### Authority

Authority: 49 U.S.C. 106(f), 106(g), 40113, 44701, 44702 and 44704; Pub. L. 115-254, 132 Stat 3281 (49 U.S.C. 44903 note).

### Source

Source: Docket No. 5066, 29 FR 18291, Dec. 24, 1964, unless otherwise noted.

### Amendments

[Amdt. 25-91, 62 FR 40705, July 29, 1997; Amdt. 25-91, 62 FR 45481, Aug. 27, 1997]