* Units: cross out if not applicable, reading Error ≤ 2,5% acceptable
** left and right half of elevator separately
Measuring of Static Hinge Moment
The relation between hinge moment and force is:
static hinge moment M = F • r,
wherein F is the force measured at the trailing edge of the control surface, and r is the horizontal distance between trailing edge
and hinge axis. F may be measured with a spring balance or another suitable scale with an error in measurement not exceeding
2.5%.
The friction of the hinge bearing should be less than 2.5 % of the maximum permissible hinge moment. If the detached control
surface is curved to the front or to the back at least three points should be used to ensure that the curvature is eliminated and
thus cannot falsify the measurement.
Measuring Procedure with Attached Control Surface (not applicable with rudder):
The surface is to be kept in horizontal position by means of the spring balance. Then move the balance slowly upwards (by
hand) and enter the force and direction of movement in the record at which the control surface overcomes the static friction and
starts going (e.g.: 11.2 N ↑ ).
After that, starting from the horizontal position again, the spring scale is to be slowly lowered until the control surface starts
moving. Note again force and direction (e.g. 10.8 N ↓ ).
Both results must be within the limits given in the above table.
Site, date Stamp Sign
Inspector Statement
The control surface masses and hinge moments are within the allowable ranges and correspond to the
production and maintenance instructions of the type.
Site, date Stamp Sign