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451 

Federal Aviation Administration, DOT 

Pt. 60, App. D 

2.d.2. .....................

Directional Static Sta-

bility.

Lateral Control Position—

±

10% of 

change from trim or 

±

0.25 in. 

(6.3 mm) or Lateral Control 
Force—

±

0.5 lb. (0.223 daN) or 

10%. Roll Attitude—

±

1.5 Direc-

tional Control Position—

±

10% 

of change from trim or 

±

0.25 in. 

(6.3 mm) or Directional Control 
Force—

±

1 lb. (0.448 daN) or 

10%. Longitudinal Control Posi-
tion—

±

10% of change from trim 

or 

±

0.25 in. (6.3 mm). Vertical 

Velocity—

±

100 fpm (0.50m/ 

sec) or 10%.

Cruise; or Climb 

(may use Descent 
instead of Climb if 
desired) Aug-
mentation On and 
Off.

Record results for at least two 

sideslip angles on either side of 
the trim point. The force may 
be shown as a cross plot for ir-
reversible systems. May be a 
series of snapshot tests.

X  This is a steady heading 

sideslip test at a fixed 
collective position. 

2.d.3. .....................

Dynamic Lateral and Directional Stability. 

2.d.3.a. ..................

Lateral-Directional Oscil-

lations.

±

0.5 sec. or 

±

10% of period. 

±

10% of time to 

1

2

or double 

amplitude or 

±

0.02 of damping 

ratio. 

±

20% or 

±

1 sec of time 

difference between peaks of 
bank and sideslip. For non-peri-
odic responses, the time history 
must be matched within 

±

10 

knots Airspeed; 

±

5

°

/s Roll Rate 

or 

±

5

° 

Roll Attitude; 

±

4

°

/s Yaw 

Rate or 

±

4

° 

Yaw Angle over a 

20 sec period roll angle fol-
lowing release of the controls.

Cruise or Climb Aug-

mentation On and 
Off.

Record results for at least two air-

speeds. The test must be initi-
ated with a cyclic or a pedal 
doublet input. Record results 
for six full cycles (12 over-
shoots after input completed) or 
that sufficient to determine time 
to 

1

2

or double amplitude, 

whichever is less. The test may 
be terminated prior to 20 sec if 
the test pilot determines that 
the results are becoming un-
controllably divergent.

X X X 

2.d.3.b. ..................

Spiral Stability ...............

±

2

° 

or 

±

10% roll angle .................

Cruise or Climb. Aug-

mentation On and 
Off.

Record the results of a release 

from pedal only or cyclic only 
turns for 20 sec. Results must 
be recorded from turns in both 
directions. Terminate check at 
zero roll angle or when the test 
pilot determines that the atti-
tude is becoming uncontrollably 
divergent.

X X X 

2.d.3.c. ...................

Adverse/Proverse Yaw ..

Correct Trend, 

±

2

° 

transient side-

slip angle.

Cruise or Climb. Aug-

mentation On and 
Off.

Record the time history of initial 

entry into cyclic only turns, 
using only a moderate rate for 
cyclic input. Results must be 
recorded for turns in both direc-
tions.

X X X 

3. Reserved 

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