205 

Federal Aviation Administration, DOT 

§ 23.207 

(6) 

Trim:  At 1.5 V

S1

or the minimum 

trim speed, whichever is higher. 

(7) 

Propeller: Full increase r.p.m. posi-

tion for the power off condition. 

[Doc. No. 27807, 61 FR 5191, Feb. 9, 1996, as 
amended by Amdt. 23–62, 76 FR 75755, Dec. 2, 
2011] 

§ 23.203

Turning flight and accelerated 

turning stalls. 

Turning flight and accelerated turn-

ing stalls must be demonstrated in 
tests as follows: 

(a) Establish and maintain a coordi-

nated turn in a 30 degree bank. Reduce 
speed by steadily and progressively 
tightening the turn with the elevator 
until the airplane is stalled, as defined 
in § 23.201(b). The rate of speed reduc-
tion must be constant, and— 

(1) For a turning flight stall, may not 

exceed one knot per second; and 

(2) For an accelerated turning stall, 

be 3 to 5 knots per second with steadily 
increasing normal acceleration. 

(b) After the airplane has stalled, as 

defined in § 23.201(b), it must be possible 
to regain wings level flight by normal 
use of the flight controls, but without 
increasing power and without— 

(1) Excessive loss of altitude; 
(2) Undue pitchup; 
(3) Uncontrollable tendency to spin; 
(4) Exceeding a bank angle of 60 de-

grees in the original direction of the 
turn or 30 degrees in the opposite direc-
tion in the case of turning flight stalls; 

(5) Exceeding a bank angle of 90 de-

grees in the original direction of the 
turn or 60 degrees in the opposite direc-
tion in the case of accelerated turning 
stalls; and 

(6) Exceeding the maximum permis-

sible speed or allowable limit load fac-
tor. 

(c) Compliance with the require-

ments of this section must be shown 
under the following conditions: 

(1) 

Wings flaps: Retracted, fully ex-

tended, and each intermediate normal 
operating position as appropriate for 
the phase of flight. 

(2) 

Landing gear: Retracted and ex-

tended as appropriate for the altitude. 

(3) 

Cowl flaps: Appropriate to configu-

ration. 

(4) 

Spoilers/speedbrakes: Retracted and 

extended unless they have no 
measureable effect at low speeds. 

(5) 

Power: 

(i) Power/Thrust off; and 
(ii) For reciprocating engine powered 

airplanes: 75 percent of maximum con-
tinuous power. However, if the power- 
to-weight ratio at 75 percent of max-
imum continuous power results in 
nose-high attitudes exceeding 30 de-
grees, the test may be carried out with 
the power required for level flight in 
the landing configuration at maximum 
landing weight and a speed of 1.4 V

SO

, 

except that the power may not be less 
than 50 percent of maximum contin-
uous power; or 

(iii) For turbine engine powered air-

planes: The maximum engine thrust, 
except that it need not exceed the 
thrust necessary to maintain level 
flight at 1.5 V

S1

(where V

S1

corresponds 

to the stalling speed with flaps in the 
approach position, the landing gear re-
tracted, and maximum landing weight). 

(6) 

Trim:  The airplane trimmed at 1.5 

V

S1.

 

(7) 

Propeller:  Full increase rpm posi-

tion for the power off condition. 

[Amdt. 23–14, 38 FR 31820, Nov. 19, 1973, as 
amended by Amdt. 23–45, 58 FR 42159, Aug. 6, 
1993; Amdt. 23–50, 61 FR 5191, Feb. 9, 1996; 
Amdt. 23–62, 76 FR 75755, Dec. 2, 2011] 

§ 23.207

Stall warning. 

(a) There must be a clear and distinc-

tive stall warning, with the flaps and 
landing gear in any normal position, in 
straight and turning flight. 

(b) The stall warning may be fur-

nished either through the inherent aer-
odynamic qualities of the airplane or 
by a device that will give clearly dis-
tinguishable indications under ex-
pected conditions of flight. However, a 
visual stall warning device that re-
quires the attention of the crew within 
the cockpit is not acceptable by itself. 

(c) During the stall tests required by 

§ 23.201(b) and § 23.203(a)(1), the stall 
warning must begin at a speed exceed-
ing the stalling speed by a margin of 
not less than 5 knots and must con-
tinue until the stall occurs. 

(d) When following procedures fur-

nished in accordance with § 23.1585, the 
stall warning must not occur during a 
takeoff with all engines operating, a 
takeoff continued with one engine in-
operative, or during an approach to 
landing. 

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