tab deflection, in degrees from arrow.
placarded: FLAP - UP, APPROACH, and DOWN. The
amount of downward extension of the flaps is
2-44. Wing Flaps.
established by position of the flap switch, and is as
follows: UP - 0%, APPROACH - 35%, and DOWN -
The all-metal slot-type wing flaps are electrically
100%. Limit switches, mounted on the right inboard flap,
operated and consist of two sections for each wing.
control flap travel. The flap control switch, limit switch,
These sections extend from the inboard end of each
and relay circuits are protected by a 5-ampere circuit
aileron to the junction of the wing and fuselage. During
breaker, placarded FLAP IND, located on the right
extension, or retraction the flaps are operated as a
single unit, each section being actuated by a separate
APPROACH cannot be selected. For intermediate flap
jackscrew actuator. The actuators are driven through
positions between APPROACH and DOWN,
flexible shafts by a single, reversible electric motor.
APPROACH position acts as an off position. To return
Wing flap movement, either up or down, is indicated in
the flaps to any position between full DOWN and
percent of travel by a flap position indicator on the center
APPROACH, place the flap switch to UP and when
of the control pedestal. Full flap extension and retraction
desired flap position is obtained, return the switch to the
time is approximately 11 seconds. The flap control
switch is also located on the control pedestal. No
emergency wing flap actuation system is provided. The
b. Wing Flap Position Indicator. Flap position in
circuit is protected by a 20-ampere push-pull circuit
percent of travel from 0 percent (UP) to 100 percent
breaker, placarded FLAP MOTOR POWER, located on
(DOWN), is shown on an indicator, placarded FLAPS on
down or extended flap position is 15 and 43 degrees,
a. Wing Flap Control Switch. Flap operation is
respectively. The flap position indicator is protected by a
controlled by a three position switch with a flap-shaped
5-ampere circuit breaker, placarded FLAP IND, located
handle on the control pedestal (fig. 2-6). The handle of
this switch is discarded: FLAP and switch positions are
Section VI. PROPELLERS
accomplished by pulling the corresponding propeller
To unfeather, the
A three-bladed aluminum propeller is installed on
propeller lever is pushed forward into the governing
each engine, These propellers are hydraulically
range. An automatic feathering system, if armed, will
controlled, constant-speed full-feathering and reversible.
sense loss of torque oil pressure and will feather an
Each propeller is controlled by engine oil acting through
unpowered propeller. Feathering springs will feather the
an engine-driven propeller governor.
propeller when it is not turning.
accomplished by the feathering springs assisted by
centrifugal force applied to the blade shank
a. Automatic Feathering. Automatic feathering can
counterweights. Governor boosted engine oil pressure
occur only when the PROP AUTOFEATHER switch is in
moves the propeller blades to the high RPM (low pitch)
the ARM position, both power levers are above 88% to
hydraulic stop and into reverse pitch.
92% N1 and the torque value of one engine drops below
propeller position is determined by a mechanically
160 to 290 ft-lbs. The autofeather system has a cross-
monitored hydraulic stop. A back-up system, referred to
interlocking safety feature designed into the control
as the secondary low pitch stop, protects against
circuit to prevent automatic feathering of both propellers.
propeller reversing in the event of failure of the primary
Before a propeller feathers automatically, the interlock
hydraulic low pitch stop system. In the event of loss of
disarms, the autofeather circuit of the opposite propeller.
oil pressure, the propeller blades will go to the feathered
After autofeathering has occurred for one propeller the
opposite propeller can be feathered only by the manual
2-46. Feathering Provisions.
b. Propeller Autofeather Switch.
The aircraft is equipped with both manual and
automatic propeller feathering. Manual feathering is
Change 7 2-35