516 

14 CFR Ch. I (1–1–19 Edition) 

Pt. 135, App. A 

engine windmilling with the propeller con-
trols in the normal position except that, if 
an approved automatic feathering system is 
installed, the propellers may be in the feath-
ered position: 

(1) 

Takeoff: landing gear extended. 

The min-

imum steady gradient of climb must be 
measurably positive at the speed 

V

1

. 

(2) 

Takeoff: landing gear retracted. 

The min-

imum steady gradient of climb may not be 
less than 2 percent at speed 

V

2

. For airplanes 

with fixed landing gear this requirement 
must be met with the landing gear extended. 

(c) 

En route climb: one-engine-inoperative. 

The maximum weight must be determined 
for each altitude and ambient temperature 
within the operational limits established for 
the airplane, at which the steady gradient of 
climb is not less 1.2 percent at an altitude 
1,000 feet above the takeoff surface, with the 
airplane in the en route configuration, the 
critical engine inoperative, the remaining 
engine at the maximum continuous power or 
thrust, and the most unfavorable center of 
gravity. 

7. 

Landing. 

(a) The landing field length de-

scribed in paragraph (b) of this section must 
be determined for standard atmosphere at 
each weight and altitude within the oper-
ational limits established by the applicant. 

(b) The landing field length is equal to the 

landing distance determined under FAR 
23.75(a) divided by a factor of 0.6 for the des-
tination airport and 0.7 for the alternate air-
port. Instead of the gliding approach speci-
fied in FAR 23.75(a)(1), the landing may be 
preceded by a steady approach down to the 
50-foot height at a gradient of descent not 
greater than 5.2 percent (3

°

) at a calibrated 

airspeed not less than 1.3

V

S

1

. 

Trim 

8. 

Trim. 

(a) 

Lateral and directional trim. 

The 

airplane must maintain lateral and direc-
tional trim in level flight at a speed of 

V

H

or 

V

MO

/

M

MO,

whichever is lower, with landing 

gear and wing flaps retracted. 

(b) 

Longitudinal trim. 

The airplane must 

maintain longitudinal trim during the fol-
lowing conditions, except that it need not 
maintain trim at a speed greater than 

V

MO

/ 

M

MO

: 

(1) In the approach conditions specified in 

FAR 23.161(c) (3) through (5), except that in-
stead of the speeds specified in those para-
graphs, trim must be maintained with a 
stick force of not more than 10 pounds down 
to a speed used in showing compliance with 
section 7 or 1.4

V

S

1

whichever is lower. 

(2) In level flight at any speed from 

V

H

or 

V

MO

/

M

MO

, whichever is lower, to either 

V

x

or 

1.4

V

S

1

, with the landing gear and wing flaps 

retracted. 

Stability 

9. 

Static longitudinal stability. 

(a) In showing 

compliance with FAR 23.175(b) and with 
paragraph (b) of this section, the airspeed 
must return to within 

±

7

1

⁄

2

percent of the 

trim speed. 

(b) 

Cruise stability. 

The stick force curve 

must have a stable slope for a speed range of 

±

50 knots from the trim speed except that 

the speeds need not exceed 

V

FC

/

M

FC

or be less 

than 1.4

V

S

1

. This speed range will be consid-

ered to begin at the outer extremes of the 
friction band and the stick force may not ex-
ceed 50 pounds with— 

(1) Landing gear retracted; 
(2) Wing flaps retracted; 
(3) The maximum cruising power as se-

lected by the applicant as an operating limi-
tation for turbine engines or 75 percent of 
maximum continuous power for recipro-
cating engines except that the power need 
not exceed that required at 

V

MO

/

M

MO

; 

(4) Maximum takeoff weight; and 
(5) The airplane trimmed for level flight 

with the power specified in paragraph (3) of 
this paragraph. 

V

FC

/

M

FC

may not be less than a speed mid-

way between 

V

MO

/

M

MO

and 

V

DF

/

M

DF,

except 

that, for altitudes where Mach number is the 
limiting factor, 

M

FC

need not exceed the 

Mach number at which effective speed warn-
ing occurs. 

(c) 

Climb stability (turbopropeller powered 

airplanes only). 

In showing compliance with 

FAR 23.175(a), an applicant must, instead of 
the power specified in FAR 23.175(a)(4), use 
the maximum power or thrust selected by 
the applicant as an operating limitation for 
use during climb at the best rate of climb 
speed, except that the speed need not be less 
than 1.4

V

S

1

. 

Stalls 

10. 

Stall warning. 

If artificial stall warning 

is required to comply with FAR 23.207, the 
warning device must give clearly distin-
guishable indications under expected condi-
tions of flight. The use of a visual warning 
device that requires the attention of the 
crew within the cockpit is not acceptable by 
itself. 

Control Systems 

11. 

Electric trim tabs. 

The airplane must 

meet FAR 23.677 and in addition it must be 
shown that the airplane is safely control-
lable and that a pilot can perform all the 
maneuvers and operations necessary to ef-
fect a safe landing following any probable 
electric trim tab runaway which might be 
reasonably expected in service allowing for 
appropriate time delay after pilot recogni-
tion of the runaway. This demonstration 
must be conducted at the critical airplane 
weights and center of gravity positions. 

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