()
de
1. da :[Downwash factor].
Amdt. 23-42, E.. 02/04/91
FAR 23.427 : Unsymmetrical loads.
(a)
[Horizontalsurfaces other than main wing and their supporting structure must be designed for unsymmetrical loads arising from yawing and slip-stream e.ects, in combination with the loads prescribed for the .ight conditions set forth in Secs.

23.421 through 23.425.

(b)
Inthe absenceof morerationaldatafor airplanesthatareconventionalin regard to location of engines, wings, horizontal surfaces other than main wing, and fuselage shape–]

′
Elodie Roux. Septembre 2003
Subpart C : Structure
(1)
100 percent of the maximum loading from the symmetrical .ight conditions may be assumed on the surface on one side of the plane of symmetry; and

(2)
Thefollowingpercentage of thatloading mustbe applied to the opposite side : % = 100 . 10(nz . 1), where nz is the speci.ed positive maneuvering load factor,butthis value may notbe morethan80percent.

(c) [For airplanesthat are not conventional(suchas airplanes withhorizontal surfaces other than main wing having appreciable dihedral or supported by the vertical tail surfaces) the surfaces and supporting structures must be designed for combined vertical andhorizontal surfaceloadsresultingfromeachprescribed .ightcondition taken separately.]
Amdt. 23-42, E.. 02/04/91
30.5 Vertical Surfaces
FAR 23.441 : Maneuvering loads.
(a)
At speeds up to VA, the vertical surfaces mustbedesignedto withstand thefollowing conditions.In computing theloads,theyawing velocity maybe assumedtobe zero :

(1)
With the airplane in unaccelerated .ight at zero yaw, it is assumed that the ruddercontrolissuddenlydisplaced tothe maximumde.ection,aslimitedby the control stops or by limit pilot forces.

(2)
[With the rudderde.ected as speci.edinparagraph(a)(1) of this section,it is assumed that the airplane yaws to the overswing sideslip angle. In lieu of a rational analysis, an overswing angle equal to 1.5 times the static sideslip angle ofparagraph(a)(3) of this section may be assumed.]

(3)
A yaw angle of 15'with the rudder control maintainedinthe neutralposition (except as limited by pilot strength).

(b)
[For commuter category airplanes, the loads imposed by the following additional maneuver must be substantiated at speeds from VA to VD/MD. When computing the tail loads–

(1)
The airplane must be yawed to the largest attainable steady state sideslip angle, with the rudder at maximum de.ection caused by any one of the follo-wing :

(i)
Control surface stops;

(ii)
Maximum available booster e.ort;

(iii) Maximum pilot rudder force as shown below :

(2)
The rudder must be suddenly displaced from the maximum de.ection to the neutral position.]

(c)
Theyaw angles speci.edinparagraph(a)(3) of this section maybe reducedif the yaw angle chosen for a particular speed cannot be exceeded in–

(1)
Steady slip conditions;

(2)
Uncoordinated rolls from steep banks; or

(3)
Sudden failure of the critical engine with delayed corrective action. Amdt. 23-48, E.. 03/11/96

RPM control knob

Mixture control knob

Carb heat or alternate air control knob

Supercharger control knob
Fig. 30.2 – Maximum Pilot Rudder Force.
FAR 23.443 : Gust loads.
(a)  Vertical surfaces must be designed to withstand, in unaccelerated .ight at speed VC, 
lateral gusts or the values prescribed for VC in Sec. 23.333(c). 
′ 

Elodie Roux. Septembre 2003
Subpart C : Structure
(b)
　
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