The trailing edges hold the flight control surfaces such as spoilers, ailerons and flaps. The trailing edge in the flap area holds the spoilers. The trailing edge in this area is used as a cover for the space between the rear spar/auxiliary spar and the flap. The trailing edge in the aileron area is used as a cover for the space between the rear spar and the aileron.

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The flaps are the devices used during takeoff and approach to give more lift to the aircraft. Each wing has one fowler-type flap. Each flap is installed on three tracks. The flaps have the components that follow:

Flaps

One fowler-flap is installed on each wing trailing edge between the inboard trailing edge and the aileron (WS73.00 and WS298.52). The flap has the components that follow:

• Front Spar
• Rear Spar
• Ribs
• Skin Panels
• Access Panels

Flap Fairings

The flap fairings are installed on the flap support assemblies at WS121.50, WS202.75, and WS263.90. The flap fairings decrease drag. They also give protection to the flap support structures. Each fairing is divided into three parts, forward, aft and tail. The forward fairing is attached to the flap support assembly and they do not move. The aft and tail fairings are attached to the forward fairing with the hinges and they move with the flap. The fairing skins are made from Aramid-Fiber Reinforced Plastics (AFRP). The frames and beams are made from clad aluminum-alloy sheets. The hinge fittings are made from machined aluminum alloy. The access panels are installed on the inner and outer sides of each fairing. The access panels are made from clad aluminum-alloy sheets.

Flap Support Assemblies

Three flap support assemblies are installed on the outer-wing box structure. The flap support assemblies include the components that follow:

• Flap Tracks
• Box Beam

Each track rail is an "I"-shape straight bar. The stop fittings are installed on the forward end of the inboard and outboard flap tracks to prevent the derailment of the carriages. The flap track is made from machined nickel-chromium molybdenum-steel bar. Each box beam has plates and the machined beam which has a channel shape. These parts are made from machined aluminum alloy.

Flap Support Structures

Three support structures are installed on the bottom side of the outer wing box and the bottom side of the flap panel. The flap support structures are made from the components that follow:

• Carriages
• Link Assemblies

The flap is held on the outer wing by carriages and the link assemblies. The carriages are installed on the flap tracks and the track support ribs. The link assemblies are installed on the flap support assemblies and the track support ribs. Each carriage has four main rollers and four side rollers. Each roller is the needle type bearing. The carriage is attached to the flap bottom surface by the pin joint. It is made from the machined aluminum alloy. Each link assembly connects the aft end of the flap support assembly and the trailing edge of the flap. It is made from machined aluminum alloy.

 

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The trailing edges of each wing consist of the inboard and outboard trailing edge sections.

The inboard trailing edge section is found on the inner side of the flap panels from WS37.92 to WS70.00. Each inboard trailing edge section includes the main landing-gear (MLG) trunnion fitting and the pulley (for the aileron control system). The MLG trunnion fitting is attached to the rear spar of the wing. The pulley and its support structure are installed aft of the MLG trunnion fitting and the auxiliary spar. The section also includes the main landing-gear bay area.

The outboard trailing edge section extends along the front of the flap and the aileron from WS80.28 to WS358.35. The outboard trailing edge section in the flap area holds the spoilers. The trailing edge section in this area is also used to cover the space between the rear spar of the wing and the flap. In the aileron area the outboard trailing edge section is used to cover the space between the rear spar and the aileron. The outboard trailing edge section is attached to the rear spar of the wing.

Both trailing edge sections have skins and ribs. The skins are made from chemically milled clad aluminum sheets. The ribs are made from machined aluminum alloy. The outboard trailing edge section includes the actuator fittings and hinge fittings to attach the spoilers and the hinge fittings aileron.

The trailing edges have the component that follows:

• Trailing Edge Access Panels

Nine access panels are installed on the trailing edges.

The inboard trailing edge section has three access panels. Two of the panels on the top outer side of the MLG trunnion fitting give access to the MLG auxiliary actuator. The other panel on the top and aft side of the MLG trunnion fitting gives access for the MLG pintle and the pulley.

The outboard trailing edge section has six access panels on the bottom. These access panels give access to the control systems of the flight control surfaces and the area that the flight control surfaces are attached.

Trailing Edge Access Panels

The access panels of the inboard and outboard trailing edge sections have skins that are made of chemically-milled aluminum alloy sheet. On the outboard trailing edge section, two types of seals that are made of silicon rubber are installed aft of each access panel. They touch the leading edge of the flap in its retracted position.

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