Navigate / EASA

CS 25.397 Control system loads

ED Decision 2016/010/R

(a)     General. The maximum and minimum pilot forces, specified in sub-paragraph (c) of this paragraph, are assumed to act at the appropriate control grips or pads (in a manner simulating flight conditions) and to be reacted at the attachment of the control system to the control surface horn.  

(b)     Pilot effort effects. In the control surface flight loading condition, the air loads on movable surfaces and the corresponding deflections need not exceed those that would result in flight from the application of any pilot force within the ranges specified in sub-paragraph (c) of this paragraph. Two-thirds of the maximum values specified for the aileron and elevator may be used if control surface hinge moments are based on reliable data. In applying this criterion, the effects of servo mechanisms, tabs, and automatic pilot systems, must be considered.

(c)      Limit pilot forces and torques. The limit pilot forces and torques are as follows:

Control

Maximum forces or torques

Minimum forces or torques

Aileron:

Stick

Wheel*

 

445 N (100 lbf)

356 DNm (80 D in.lb)**

 

178 N (40 lbf)

178 DNm (40 D in.lbf)

Elevator:

Stick

Wheel (symmetrical)

Wheel (unsymmetrical)†

 

1112 N (250 lbf)

1335N(300 lbf)

 

445 N (100 lbf)

445 N(100 lbf)

445 N (100 lbf)

Rudder

1335 N (300 lbf)

578 N 130 lbf

*The critical parts of the aileron control system must be designed for a single tangential force with a limit value equal to 1·25 times the couple force determined from these criteria.

**D = wheel diameter in m (inches)

†The unsymmetrical forces must be applied at one of the normal handgrip points on the periphery of the control wheel.

(d)     For aeroplanes equipped with side stick controls, designed for forces to be applied by one wrist and not by the arms, the limit pilot forces are as follows:

(1)     For all components between and including the handle and its control stops:

PITCH

ROLL

Nose Up

890 N (200 lbf)

Roll Left

445 N (100lbf)

Nose Down

890 N (200 lbf)

Roll Right

445 N (100 lbf)

 

(2)     For all other components of the side stick control assembly, but excluding the internal components of the electrical sensor assemblies, to avoid damage as a result of an in-flight jam:

PITCH

ROLL

Nose Up

556 N (125 lbf)

Roll Left

222 N (50 lbf)

Nose Down

556 N (125 lbf)

Roll Right

222 N (50 lbf)

[Amdt 25/13]

[Amdt 25/18]