229
Federal Aviation Administration, DOT
Pt. 60, App. C
2.c.3.a.
........
Long-Term Response.
±
10% of calculated period,
±
10% of time to
1
⁄
2
or dou-
ble amplitude, or
±
0.02 of
damping ratio.For non-peri-
odic responses, the time
history must be matched
within
±
3
°
pitch; and
±
5 kts
airspeed over a 20 sec pe-
riod following release of the
controls.
Cruise Augmentation On and
Off.
For periodic responses,
record results for three full
cycles (6 overshoots 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 re-
sults are becoming uncon-
trollably divergent.
X
X
X
The response may be
unrepeatable throughout
the stated time for certain
helicopters. In these cases,
the test should show at
least that a divergence is
identifiable. For example:
Displacing the cyclic for a
given time normally excites
this test or until a given
pitch attitude is achieved
and then return the cyclic
to the original position. For
non-periodic responses, re-
sults should show the
same convergent or diver-
gent character as the flight
test data.
2.c.3.b.
........
Short-Term Response.
±
1.5
°
Pitch or
±
2
°
/sec. Pitch
Rate.
±
0.1 g Normal Accel-
eration.
Cruise or Climb. Augmenta-
tion On and Off.
Record results for at least
two airspeeds.
X
X
X
A control doublet inserted at
the natural frequency of the
aircraft normally excites
this test. However, while
input doublets are pre-
ferred over pulse inputs for
Augmentation-Off tests, for
Augmentation-On tests,
when the short-term re-
sponse exhibits 1st-order
or deadbeat characteristics,
longitudinal pulse inputs
may produce a more co-
herent response.
2.c.4.
...........
Maneuvering Stability.
Longitudinal Control Posi-
tion—
±
10% of change from
trim or
±
0.25 in. (6.3 mm)
or Longitudinal Control
Forces—
±
0.5 lb. (0.223
daN) or
±
10%.
Cruise or Climb. Augmenta-
tion On and Off.
Record results for at least
two airspeeds at 30
°
–45
°
roll angle. The force may
be shown as a cross plot
for irreversible systems.
May be a series of snap-
shot tests.
X X X
2.d.
.............
Lateral and Directional Handling Qualities
2.d.1.
..........
Control Response
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