(b)
[The airspeedmust return to within the tolerances speci.edfor applicable categories of airplaneswhenthe controlforceisslowly released at any speed withinthe speed range speci.edinparagraph(a) of this section.The applicabletolerances are–
(1)
The airspeed must return to within plus or minus 10 percent of the original trim airspeed; and
(2)
For commuter category airplanes, the airspeed must return to within plus or minus 7.5 percent of the original trim airspeed for the cruising condition speci.ed in Sec. 23.175(b).]
(c)
The stick force must vary with speed so that any substantial speed change results in
a stickforce clearlyperceptibletothepilot. Amdt. 23-34, E.. 02/17/87
FAR 23.175 : Demonstration of static longitudinal stability.
(a)
[Climb. The stick force curve must have a stable slope at speeds between 85 and 115 percent of the trim speed, with–
(1)
Flaps retracted;
(2)
Landing gear retracted;
(3)
Maximum continuouspower; and
(4)
The airplane trimmed at the speed usedin determining the climbperformance required by Sec. 23.69(a).
(b)
Cruise. With .aps and landing gear retracted and the airplane in trim with power forlevel .ight at representativecruising speedsathigh andlowaltitudes,including speeds up to VNO or VMO/MMO as appropriate, except that the speed need not exceed VH –
(1) For normal, utility, andacrobatic category airplanes, the stickforce curve must have a stable slope atall speeds within a range thatis thegreater of15percent of the trim speed plus the resulting free return speed range, or 40 knots plus the resulting free return speed range, above and below the trim speed, except that the slope need not be stable–
(i)
At speeds less than 1.3 VS1 ; or
(ii)
For airplanes with VNE established underSec.23.1505(a), at speedsgrea-ter than VNE ; or
(iii) For airplanes with VMO/MMO established under Sec. 23.1505(c), at speeds greater than VFC/MFC.
′
Elodie Roux. Septembre 2003
Subpart B : Flight
(2) For commuter categoryairplanes, the stickforce curve musthave a stable slope at all speeds within a range of 50 knots plus the resulting free return speed range, above and below the trim speed, except that the slope need not be stable–
(i)
At speeds less than 1.4 VS1 ; or
(ii)
At speeds greater than VFC/MFC ; or
(iii) At speeds that require a stick force greater than 50 pounds.
(c)
Landing. The stick force curve must have a stable slope at speeds between 1.1 VS1 and 1.8 VS1 with–
(1)
Flaps in the landing position;
(2)
Landinggear extended; and
(3)
The airplane trimmed at–
(i) VREF, orthe minimumtrim speedifhigher, withpower o.; and
(ii)
VREF with enough power to maintain a 3 degree angle of descent.] Amdt. 23-50, E.. 3/11/96
FAR 23.177 : Static directional and lateral stability. 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址:FAA规章 美国联邦航空规章 Federal Aviation Regulations 1(135)