The empennage/tail is found between FS669.76 and FS928.00. It is made from external sheet metal skins and is made stronger with stringers, machined frames. The empennage/tail includes the aft equipment compartment, wing fairings (which has the battery compartment), auxiliary power unit (APU) and the tail-cone. It also has the attachment points for the vertical stabilizer. The forward skin panels and wing fairings (including the battery compartment) also extend into the aft fuselage area.

The tail-cone is a fairing that contains the auxiliary power unit (APU). It also contains related systems which include the APU mounting struts and the APU muffler. The tail-cone is a one piece component made from an epoxy/graphite composite material. The tail-cone structure is made stronger by co-cured stiffeners. Two panels which can be removed give access to the internal components.

The aft equipment compartment is an area which is part of the empennage/tail. It is made from the same skins, frames, stringers, door surround structure as the empennage/tail. The aft equipment compartment extends from FS669.76 to FS801.00 and has a walkway. The aft equipment compartment gives an area for the installation of different components from other aircraft systems.

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The skins are made from aluminum-alloy sheets and made stronger with the stringers and the frames. The lower skin has a latch door for the access to the ground air servicing-connection. The stringers are made from extruded Z-sections and attached to the frames. They extend the full length of the aft equipment compartment. At the bottom, the stringers are assembled differently because there is a surround structure for the aft equipment-compartment door.

The surround structure for the aft equipment-compartment door extends between FS724.70 and FS756.25. The frames at FS724.70 and FS756.25 are the forward and the aft structural parts of the surround structure. They are made stronger with the intercostals, angles, gussets and doublers.

The attachment fittings for the vertical stabilizer to the fuselage are made from a machined aluminum-alloy. They are attached to the front, middle and rear spars of the vertical stabilizer at the top of the fuselage at FS808.00, FS839.00 and FS871.00.

There are seven frames installed at FS688.45, FS707.00, FS724.70, FS740.00, FS756.25, FS772.19 and FS788.53. The two frames at FS724.70 and FS772.19 are made from a machined aluminum-alloy to hold the power plant. The other five frames are made from clad aluminum-alloy sheets.

The wing fairings support-structure includes three frames, two longitudinal webs, the battery compartment and angles. The three frames are made from clad aluminum-alloy sheets and are attached to the lower skin at FS669.76, FS707.00 and FS724.40. The two longitudinal webs are made from clad aluminum-alloy sheets and attached to the frame and lower skin.

The battery compartment extends from the empennage/tail section to the aft fuselage section. The aft part of the battery compartment which is in the empennage/tail section is found between FS669.76 and FS680.00 at LBL14.37. It has two webs, an aft and a longitudinal angle which are all attached to the fuselage skin panels. The floor of the battery compartment is made from clad aluminum-alloy sheets and is attached to the tracks of the battery tray.

There are four APU support-mounting attachment-fittings installed on the aft side of the rear canted frame and made from machined stainless steel.

The wing fairings and the vertical stabilizer also attach to the empennage/tail structure.

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The tail-cone is found at the rear of the aircraft empennage/tail. The tail-cone is attached to the rear part of the empennage/tail with rivets.

The tail-cone contains the auxiliary power unit (APU). The APU has support mounting and attachment fittings which attach the APU to the canted frame of the empennage/tail. The APU muffler connects to the tail-cone at the rear, through an exhaust embellisher.

The muffler has two side supports on its front that attaches thru two insulation blocks to the two muffler mounts on the tail-cone sides. The muffler mounts are attached to the tail-cone sides with rivets.

A large panel at the bottom of the tail-cone gives access to remove and install the APU. A smaller panel on the left side gives access to components in the tail-cone which helps to remove and install the APU. These panels attach to the aluminum support frames of the panel openings in the tail-cone.

The tail-cone has two titanium firewalls. The forward firewall gives fire protection to the fuselage area forward of the tail-cone. The upper firewall gives fire protection to the empennage structure above the tail-cone. Both firewalls are attached to the tail-cone with rivets.

The tail-cone skin is made from a carbon composite material (graphite). It has five plies of carbon fabric with a ply of copper mesh on the external side for lightning protection. The tail-cone is made from two pieces, a top and bottom half. There are six more plies of carbon fabric with an overlap along the splice line of these two halves to make it stronger.

There are six more plies of carbon fabric around the edges of the panel openings to make them stronger. There is an aluminum support frame and one layer of fiberglass fabric on the internal surface of each opening for protection against a galvanic potential.

The tail-cone has 15 co-cured stiffeners from the front to the rear along its internal surface. The part of the tail-cone which connects to the empennage/tail has six more plies of carbon fabric around the edges to make them stronger. The part which connects to the empennage/tail also has one layer of fiberglass fabric on the internal surface for protection against a galvanic potential. The rear part of the tail-cone has two more plies of carbon fabric with an overlap to make it stronger. Two NACA inlets give ram air to decrease the temperature of the inner side of the tail-cone and the APU generator. The APU inlet duct on the right side gives airflow to the APU.

There are three vents which give an exhaust to the air in the tail-cone. There is one vent on the bottom center, one on the top left side, and one on the top right side of the tail-cone. The cold ram air which flows through the compartment of the tail-cone then exits to the ambient air by these three vents.

There is a drain hole connected to a tail-cone drain mast on the forward bottom of the tail-cone. The tail-cone drain mast removes liquids which can collect in the compartment of the tail-cone. There are two openings in the APU access panel. They are immediately aft of the tail-cone drain hole and give an exhaust for the muffler drain, and the fuel and inlet plenum drain.

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The aft equipment-compartment floor includes three floor panels and the floor support structure. The first floor panel extends from FS685.00 to FS724.00. The second floor panel extends from FS756.25 to FS 772.19. The last floor panel extends from FS772.19 to FS801.00. The area between the first and the second floor panel (FS724.70 to FS756.25) has the opening at the bottom of the fuselage for the aft equipment-compartment door.

All three floor panels are made from a Nomex honeycomb core which is bonded with fiberglass. Each panel attaches to the floor support structure with screws, washers, and nut plates. The top surface of each panel has antiskid tape bonded to it to give a surface which is not slippery. The antiskid tape makes it safer for personnel to do their work in that area.

Also, below the first floor panel there is an aluminum cover and some aluminum shields to prevent hydraulic fluid contamination to the other system units.

The floor support structure is made from legs, beams and angles. They attach to the structure of the empennage/tail at frames FS688.45, FS707.00, FS724.70, FS756.25, FS772.19 and FS788.53 with rivets.

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Component Location Index
IDENT	DESCRIPTION	LOCATION	IPC REF
-	AFT EQUIPMENT-COMPARTMENT FLOOR FROM FS685.00 TO FS724.00	PANEL(S) 311ALF	53-52-01
-	AFT EQUIPMENT-COMPARTMENT FLOOR FROM FS756.25 TO FS772.19	PANEL(S) 311BLF	53-52-01
-	FT EQUIPMENT-COMPARTMENT FLOOR FROM FS772.19 TO FS801.00	PANEL(S) 311CLF	53-52-01

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