2A-27-80: Flight Controls Gust Lock
1. General Description:
The flight controls gust lock secures the aircraft moveable surfaces in stabilized
positions to prevent damage to the surfaces and attached control linkages from
high winds or jet blast. A GUST LOCK handle on the copilot side of the cockpit
center console (see Figure 23) is connected through a system of cables, pulleys
and rods to hooks or latches that engage the mechanical linkages of flight controls
to prevent movement. The control surfaces are locked in positions that offer the
best protection to the aircraft. The ailerons and rudder are locked in neutral faired
positions, and the elevators are locked in a slightly trailing edge down position so
that any wind force would tend to maintain weight on the nosewheel to preserve
aircraft stability.
NOTE:
The gust lock is effective in preventing flight control
movement during wind speeds up to sixty knots (60
kts). If weather conditions are forecast to include
stronger winds, consideration should be given to
securing the aircraft within a hangar or other suitable
shelter.
2. Description of Subsystems, Units and Components:
A. GUST LOCK Handle:
The aircraft gust lock is engaged with the T-shaped handle on the cockpit
center console. In order to move the handle from either the engaged or
disengaged position, a spring loaded latch on the back of the handle must
be depressed. The spring latch prevents inadvertent engagement and also
maintains engagement of the gust lock once selected. The handle rotates
aft from the horizontal disengaged position up to a ninety degree (90°)
vertical position when engaged in order provide a strong visual cue that the
aircraft flight controls are locked.
B. Flight Control Latches:
As the GUST LOCK handle is rotated aft and up, the motion is translated
by a cable, rods and pulleys to the locking mechanisms on the flight control
linkages. The lateral motion of the single cable rotates pulleys that in turn
move latching arms into position to engage the command input links of the
flight controls. The latches will not lock in the engaged position until the
flight control is placed in the specified position necessary to minimize the
effect of wind forces on the aircraft. Section 03-06-20: After Landing /
Shutdown contains the following CAUTION notification:
ENSURE HYDRAULIC PRESSURE IS DEPLETED PRIOR TO
ENGAGING THE GUST LOCK. IF IT IS NOT POSSIBLE TO READ
HYDRAULIC PRESSURES BECAUSE THE AIRCRAFT IS WITHOUT
ELECTRICAL POWER, CYCLE THE CONTROLS WITH THE CONTROL
COLUMN, YOKE AND RUDDER PEDALS TO DEPLETE RESIDUAL
HYDRAULIC PRESSURE.
C. Mechanical Power Lever Interlock:
A mechanical interlock within the cockpit center pedestal prevents
advancing the power levers more than six percent (6%) forward of ground
OPERATING MANUAL
PRODUCTION AIRCRAFT SYSTEMS 2A-27-00
Page 91
August 14/03
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