DOC AIRBUS | AMM A320FTRIMMABLE HORIZONTAL STABILIZER SPAR BOX - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General.
A. THS Spar Box.
- The horizontal stabilizer spar box is the primary structural component of the horizontal stabilizer. All other components are attached to it.
The completed horizontal stabilizer has a left-hand (LH) spar box, a right-hand (RH) spar box and a center joint. These three components make a single unit which you can not disassemble. They are made of laminations of Carbon Fiber Reinforced Plastic (CFRP).
Horizontal Stabilizer Spar BoxA. Primary Components.
- The primary components of the LH and the RH spar boxes are a front spar, a rear spar, 13 ribs (R2 thru R14) and an upper and a lower skin shell. Hi-Lok fasteners attach them. Integrated stringers make the skin shells stronger.
B. Rear Spar Attachments.
- Each rear spar has six hinge arms and a diagonal strut to hold the elevators. Two fittings for the attachment of the elevator servo control units are installed in line with R7 and R8. The rear spars also have the LH and RH aft attach fittings for the installation of the horizontal stabilizer. The attach fittings connect the horizontal stabilizer to the structure of the rear fuselage. They are installed in line with R3 and R4.
C. Hoisting Points.
- The LH and RH spar boxes each have two hoisting points on the upper surface. Each hoisting point has a hoisting plug which is installed in the spar box structure, the hoisting points make a smooth surface with the stabilizer. When you use the hoisting points you must remove the hoisting plugs and install the hoisting lugs in position.
D. Resting Points.
- To put the horizontal stabilizer on a support when it is removed, the spar box has resting points. Each side has four resting points on the lower surface. Each resting point has a plug which is installed in the spar box structure. When you use the resting points, you must remove the plugs and install the rest ing pins.
E. Levelling Points.
- The LH and RH spar boxes each have four levelling points on the lower surface.
F. Center Joint.
- The center joint connects the LH and RH spar boxes to make one unit. It has the forward attach fittings of the horizontal stabilizer. The attach fittings attach the horizontal stabilizer to the trim actuator.