Amdt. 25-23, E. 5/8/70
FAR25.672:[Stability augmentation and automatic andpower-operated systems.]
[Ifthefunctioning of stability augmentationor other automatic orpower-operated systemsisnecessarytoshowcompliancewith the .ight characteristicsrequirements of this part, such systems must comply with Sec. 25.671 and the following :
(a)
A warning which is clearly distinguishable to the pilot under expected .ight conditions without requiring his attention must be provided for any failure in the stability augmentation system orin any other automatic orpower-operated system which could result in an unsafe condition if the pilot were not aware of the failure. Warning systems must not activate the control systems.

(b)
The design of the stability augmentation system or of any other automatic or power-operated system must permit initial counteraction of failures of the type speci.ed in Sec. 25.671(c) without requiring exceptional pilot skill or strength,by eitherthedeactivation of the system, or afailedportionthereof, or by overriding the failure by movement of the .ight controls in the normal sense.

(c)
It must be shown that after any single failure of the stability augmentation system or any other automatic or power-operated system–

(1) The airplane is safely controllable when the failure or malfunction occurs atany speed oraltitude withinthe approved operatinglimitationsthatis critical for the type of failure being considered;
′
Elodie Roux. Septembre 2003
Subpart D : Design and Construction
(2)
The controllabilityand maneuverability requirements of thispart are met withinapractical operational.ight envelope(forexample, speed,altitude, normal acceleration, and airplane con.gurations) whichisdescribedin the Airplane Flight Manual; and

(3)
The trim, stability, andstall characteristics are notimpairedbelow alevel needed to permit continued safe .ight and landing.]

Amdt. 25-23, E.. 5/8/70
FAR25.673 :[Removed.]
[Removed.]
Amdt. 25-72, E.. 8/20/90

FAR 25.675 : Stops.
(a)
[Eachcontrol system must have stops thatpositivelylimit the range of motion of each movable aerodynamic surface controlled by the system.]

(b)
Each stop must be located so that wear, slackness, or take-up adjustments will not adversely a.ect the control characteristics of the airplane because of a change in the range of surface travel.

(c)
Each stop must be able to withstand any loads corresponding to the design conditions for the control system.

Amdt. 25-38, E.. 2/1/77
FAR 25.677 : Trim systems.
(a)
Trim controls must be designed to prevent inadvertent or abrupt operation and to operate in the plane, and with the sense of motion, of the airplane.

(b)
There must be means adjacent to the trim control to indicate the direction of the control movement relative to the airplane motion. In addition, there must be clearly visible means to indicate the position of the trim device with respect to the range of adjustment.

(c)
[Trim control systems must be designed to prevent creeping in .ight. Trim tab controls must be irreversible unless the tab is appropriately balanced and shown to be free from .utter.]

(d)
If an irreversible tab control system is used, the part from the tab to the attachment of the irreversible unit to the airplane structure must consist of a rigid connection.

Amdt. 25-23, E.. 5/8/70
FAR 25.679 : Control system gust locks.
(a) There mustbe adevice topreventdamage to the control surfaces(including tabs), and to the control system,fromgusts striking the airplane whileit is on the ground or water. If the device, when engaged, prevents normal operation of the control surfaces by the pilot, it must–
(1)
Automaticallydisengage whenthepilotoperatestheprimary.ight controls in a normal manner; or
　
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本文鏈接地址：FAA規(guī)章 美國聯(lián)邦航空規(guī)章 Federal Aviation Regulations 3(76)