spaschal on DSK3GDR082PROD with CFR

Federal Aviation Administration, DOT

Section 25.231

and O of this part, as applicable, in accordance with Section 25.21(g), for the en
route configuration;
(3) The most critical of the holding
ice accretion(s) defined in Appendices C
and O of this part, as applicable, in accordance with Section 25.21(g), for the holding
configuration(s);
(4) The most critical of the approach
ice accretion(s) defined in Appendices C
and O of this part, as applicable, in accordance with Section 25.21(g), for the approach configuration(s); and
(5) The most critical of the landing
ice accretion(s) defined in Appendices C
and O of this part, as applicable, in accordance with Section 25.21(g), for the landing
and go-around configuration(s).
(f) The stall warning margin must be
sufficient in both non-icing and icing
conditions to allow the pilot to prevent
stalling when the pilot starts a recovery maneuver not less than one second
after the onset of stall warning in slowdown turns with at least 1.5 g load factor normal to the flight path and airspeed deceleration rates of at least 2
knots per second. When demonstrating
compliance with this paragraph for
icing conditions, the pilot must perform the recovery maneuver in the
same way as for the airplane in nonicing conditions. Compliance with this
requirement must be demonstrated in
flight with - 
(1) The flaps and landing gear in any
normal position;
(2) The airplane trimmed for straight
flight at a speed of 1.3 VSR; and
(3) The power or thrust necessary to
maintain level flight at 1.3 VSR.
(g) Stall warning must also be provided in each abnormal configuration
of the high lift devices that is likely to
be used in flight following system failures (including all configurations covered by Airplane Flight Manual procedures).
(h) The following stall warning margin is required for flight in icing conditions before the ice protection system
has been activated and is performing
its intended function. Compliance must
be shown using the most critical of the
ice accretion(s) defined in Appendix C,
part II, paragraph (e) of this part and
Appendix O, part II, paragraph (d) of
this part, as applicable, in accordance
with Section 25.21(g). The stall warning mar-

gin in straight and turning flight must
be sufficient to allow the pilot to prevent stalling without encountering any
adverse flight characteristics when:
(1) The speed is reduced at rates not
exceeding one knot per second;
(2) The pilot performs the recovery
maneuver in the same way as for flight
in non-icing conditions; and
(3) The recovery maneuver is started
no earlier than:
(i) One second after the onset of stall
warning if stall warning is provided by
the same means as for flight in nonicing conditions; or
(ii) Three seconds after the onset of
stall warning if stall warning is provided by a different means than for
flight in non-icing conditions.
(i) In showing compliance with paragraph (h) of this section, if stall warning is provided by a different means in
icing conditions than for non-icing conditions, compliance with Section 25.203 must
be shown using the accretion defined in
appendix C, part II(e) of this part. Compliance with this requirement must be
shown using the demonstration prescribed by Section 25.201, except that the deceleration rates of Section 25.201(c)(2) need not
be demonstrated.
[Doc. No. 5066, 29 FR 18291, Dec. 24, 1964, as
amended by Amdt. 25-7, 30 FR 13118, Oct. 15,
1965; Amdt. 25-42, 43 FR 2322, Jan. 16, 1978;
Amdt. 25-108, 67 FR 70827, Nov. 26, 2002;
Amdt. 25-121, 72 FR 44668, Aug. 8, 2007; Amdt.
25-129, 74 FR 38339, Aug. 3, 2009; Amdt. 25-140,
79 FR 65526, Nov. 4, 2014]

GROUND AND WATER HANDLING
CHARACTERISTICS
Section 25.231 Longitudinal
control.

stability

(a) Landplanes may have no uncontrollable tendency to nose over in any
reasonably expected operating condition or when rebound occurs during
landing or takeoff. In addition - 
(1) Wheel brakes must operate
smoothly and may not cause any undue
tendency to nose over; and
(2) If a tail-wheel landing gear is
used, it must be possible, during the
takeoff ground run on concrete, to
maintain any attitude up to thrust line
level, at 75 percent of VSR1.
(b) For seaplanes and amphibians,
the most adverse water conditions safe

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