VERTICAL STABILIZER SPAR BOX - DESCRIPTION AND OPERATION

** ON A/C NOT FOR ALL

1. General
The vertical stabilizer spar box is the primary structural component of the vertical stabilizer. All other components of the vertical stabilizer are attached to it.

** ON A/C NOT FOR ALL

2. Component Location

Vertical Stabilizer Spar Box

** ON A/C NOT FOR ALL

3. Description

A. Spar Box Structure

(1) The vertical stabilizer spar box has a front, center and rear spar, ribs and side shells. All components are made of laminations of the Carbon Fiber Reinforced Plastic (CFRP).

(2) Seven ruddre hinge arms, the hinge arm fittings and three actuator fittings are made of aluminum alloy. They are attached to the rear spar and the side shells. Hi-Lok fasteners are used to attach them.

(3) The left-hand and right-hand side shells are made by a one-shot-bonding technique. The skin, stringers, webs and three fuselage attachment fittings are one unit.

(4) The front spar and the rear spar are riveted between the two side shells. Hi-Lok rivets are used for the installation. The spars have a number of holes to give access to the inside of the spar box. An intermediate spar is riveted between rib 1 and rib 2. Each spar has a transverse-load fitting at its lower end.

(5) The spar box has eleven ribs. Except for rib 1 and rib 2, they are at right angles to the rear spar. The center spar divides rib 1 into two. All ribs are riveted to the side shells, webs and through angles to the spars. Hi-Lok fasteners are used to attach them.

(6) Two hoisting points are installed on each side of the spar box. Each hoisting point has a threaded sleeve which is bonded into the side shell. There is a plastic plug in each hoisting point, that must be removed before the hoist fitting is installed. When the hoisting points are not in use they are covered with self adhesive disks.

(7) Each side shell has four levelling points.

[Rev.10 from 2021] 2026.04.01 02:05:45 UTC