Ata 51-57 Structure

Training Manual ATA 51-57 – Structures

Boeing 737-300/400/500 –CFM56-3 ATA 104 - Level 3 B1/B2

FOR TRAINING PURPOSES ONLY 1

ATA 51 - 57 STRUCTURES

Revision 1/ October 2011



FOR TRAINING PURPOSES ONLY 2

For training purposes only.

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FOR TRAINING PURPOSES ONLY

TABLE OF CONTENTS

ATA 52-57……………………………………………………………………………………………………………………..9

DIMENSION AND AREAS…………………………………………………………………………………………………..10

INTRODUCTION……………………………………………………………………………………………………………..10

MAINTENANCE PRACTICES……………………………………………………………………………………………..12

PRINCIPAL DIMENSIONS AND AREAS…………………………………………………………………………………14

LIFTING AND SHORING / JACKING……………………………………………………………………………………..18

TOWING AND TAXING…………………………………………………………………………………………………….20

POWERPLANT AND INLET DANGER AREAS…………………………………………………………………...…….22

WARNING PLACARDS…………………………………………………………………………………………………….25

ATA 53 FUSELAGE………………………………………………………………………………………………………..27

53-00 GENERAL……………………………………………………………………………………………………………27

FUSELAGE GENERAL DESCRIPTION………………………………………………………………………………….29

FUSELAGE GENERAL DESCRIPTION………………………………………………………………………………….30

FUSELAGE GENERAL DESCRIPTION (CONT.)……………………………………………………………………….32

ATA 57 WINGS……………………………………………………………………………………………………………..34

57-00 GENERAL……………………………………………………………………………………………………………34

WINGS GENERAL DESCRIPTION……………………………………………………………………………………….34

WINGS GENERAL DESCRIPTION (CONT)……………………………………………………………………………..36

ATA 54 NACELLES / PYLONS…………………………………………………………………………………………...40

54-00 GENERAL…………………………………………………………………………………………………………….40

STRUT………………………………………………………………………………………………………………………..40

NACELLE…………………………………………………………………………………………………………………….43

3




ATA 55 STABILIZER……………………………………………………………………………………………………….46

55-10 HORIZONTAL STABILIZER……………………………………………………………………………………….46

GENERAL DESCRIPTION………………………………………………………………………………………………...46

GENERAL DESCRIPTION (CONT)………………………………………………………………………………………47

55-30 VERTICAL STABILIZER…………………………………………………………………………...………………52

GENERAL DESCRIPTION…………………………………………………………………………………………………52

ATA 52 DOORS…………………………………………………………………………………………………………….56

52-00 GENERAL……………………………………………………………………………………………………………56

INTRODUCTION……………………………………………………………………………………………………………56

52-10 PASSENGER / CREW……………………………………………………………………………………………..59

ENTRY DOOR………………………………………………………………………………………...……………………59

ENTRY DOOR MECHANISM……………………………………………………………………………………………..62

FORWARD ENTRY DOOR OPERATION……………………………………………………………………………….67

CAM PLATE OPERATION………………………………………………………………………………………………...69

UPPER HINGE / GUIDE ARM GEOMETRY…………………………………………………………………………….71

52-40 SERVICE……………………………………………………………………………………………………………..73

GALLEY SERVICE DOOR…………………………………………………………………………………………………73

LOWER NOSE COMPARTMENT ACCESS DOOR…………………………………………………………………….75

ELECTRONIC EQUIPMENT COMPARTMENT ACCESS DOOR…………………………………………………….77

ELECTRONIC EQUIPMENT COMPARTMENT ACCESS DOOR (CONT)…………………………………………..80

4




52-20 EMERGENCY EXIT………………………………………………………………………………………….82

EMERGENCY EXIT HATCH……………………………………………………………………………………….82

EMERGENCY HATCH DETAILS………………………………………………………………………………….84

EMERGENCY EXIT HATCH OPERATION………………………………………………………………………87

52-30 CARGO………………………………………………………………………………………………………..89

CARGO COMPARTMENT DOORS……………………………………………………………………………….89

CARGO DOOR OPERATION……………………………………………………………………………………...94

FLIGHT COMPARTMENT DOOR EMERGENCY EXIT FEATURE……………………………...……………97

FLIGHT COMPARTMENT DOOR LOCK…………………………………………………………………………99

DOOR LOCK OPERATION………………………………………………………………………………..……..101

FLIGHT COMPARTMENT DOOR EMERGENCY EXIT FEATURE………………………………………….103

52-70 DOOR WARNING………………………………………………………………………………………..…106

DOOR UNLOCK INDICATORS………………………………………………………………………………...…106

ATA 56 WINDOWS…………………………………………………………………………………………………109

56-00 GENERAL……………………………………………………………………………………………………109

INTRODUCTION……………………………………………………………………………………………………109

56-10 FLIGHT COMPARTMENT………………………………………………………………………………….111

FLIGHT COMPARTMENT WINDOWS……………………………………………………………………………111

WINDOW NO. 1……………………………………………………………………………………………………...114

WINDOW NO. 3 (CONFIG 1)………………………………………………………………………………………116

WINDOWS NO. 4 & 5……………………………………………………………………………………………….118

WINDOWS NO. 2……………………………………………………………………………………………………120

5




56-20 PASSENGER COMPARTMENT………………………………………………………………………………122

FUNCTIONAL DESCRIPTION………………………………………………………………………………………...122

SEAL LEAK DETECTION………………………………………………………………………………...……………124

EDGE DAMAGE…………………………………………………………………………………………………………126

WINDOW CONCAVITY…………………………………………………………………………………………………128

56-40 INSPECTION AND OBSERVATION…………………………………………………………………………..130

INSPECTION WINDOW………………………………………………………………………………………………...130

ATA 25 EQUIPMENT / FURNISHING…………………………………………………………………………………133

25-00 GENERAL…………………………………………………………………………………………………………133

INTRODUCTION…………………………………………………………………………………………………………133

25-10 FLIGHT COMPARTMENT………………………………………………………………………………………135

FLIGHT COMPARTMENT EQUIPMENT LOCATION……………………………………………………………….135

PILOTS’ SEAT……………………………………………………………………………………………………………137

PILOTS’ SEAT REMOVAL & INSTALLATION………………………………………………………………………..139

OBSERVER’S SEAT…………………………………………………………………………………………………….141

6




25-20 PASSENGER COMPARTMENT……………………………………………………………………………………….143

COMPONENT FUNCTIONAL DESCRIPTION……………………………………………………………………………….143

PASSENGER COMPARTMENT SEATS……………………………………………………………………………………..145

PASSENGER COMPARTMENT SEATS (CONT)……………………………………………………………………………147

SIDEWALL LININGS…………………………………………………………………………………………………………….149

WINDOW REVEAL ASSEMBLY……………………………………………………………………………………………….151

SIDEWALL RISER PANELS AND AIR GRILLES……………………………………………………………………………153

SCULPTURED CEILING PANELS…………………………………………………………………………………………….155

CEILING PANEL HINGE ASSEMBLY…………………………………………………………………………………………155

PASSENGER SERVICE UNITS………………………………………………………………………………………………..157

OVERHEAD STOWAGE COMPARTMENT…………………………………………………………………………………..160

OVERHEAD STOWAGE COMPARTMENTS (CONT)……………………………………………………………………….162

25-30 BUFFET / GALLEY………………………………………………………………………………………………………164

GALLEY LOCATIONS AND IDENTIFICATION……………………………………………………………………………….164

GALLEY INSTALLATION………………………………………………………………………………………………………..166

GALLEY SERVICE POWER (CONFIG. 1)…………………………………………………………………………………….168

GALLEY SERVICE POWER (CONFIG. 2)…………………………………………………………………………………….170

25-40 LAVATORIES……………………………………………………………………………………………………………..172

LAVATORIY EQUIPMENT………………………………………………………………………………………………………172

25-50 CARGO COMPARTMENTS……………………………………………………………………………………………..174

CARGO COMPARTMENTS……………………………………………………………………………………………………..174

CARGO NET………………………………………………………………………………………………………………………176

7




25-60 EMERGENCY……………………………………………………………………………………………………………..178

EMERGENCY EQUIPMENT…………………………………………………………………………………………………….178

ESCAPE STRAP………………………………………………………………………………………………………………….180

DOOR MOUNTED ESCAPE SLIDES…………………………………………………………………………………………..182

ESCAPE SLIDE MAINTENANCE PRACTICES……………………………………………………………………………….184

8




ATA 52-57

9




DIMENSION AND AREAS

THE AIRPLANE IS A METAL LOW-WING MONOPLANE WITH A FULL CANTILEVER WING AND

TAIL SURFACES, SEMI-MONOCOQUE FUSELAGE, AND FULLY RETRACTABLE TRICYCLE-

TYPE LANDING GEAR.

THE TWO POWERPLANTS ARE LOCATED ON THE LEFT AND RIGHT WING ON SHORT

STRUTS BELOW AND FORWARD OF THE WING.

THE BOEING 737-300 / -400 / -500 TWIN ENGINE AIRPLANE IS DESIGNED FOR SHORT TO

MEDIUM RANGE OPERATION.

10




Figure 1

11




MAINTENANCE PRACTICES

General

The airplane is divided into stations, waterlines, and buttock lines. They are measured in inches. They will help you

quickly identify the location of components, the center of gravity and the weight distribution. Standard Abbreviations

and Definitions:

FUSELAGE

BSTA, BS, or STA

Body (Fuselage) Station. A plane that is perpendicular to the fuselage centerline. It is measured from a point 130.00

inches forward of the nose.

BBL or BL

Body (Fuselage) Buttock Line. A vertical plane that is parallel to the vertical centerline plane, BBL 0.00. It is found by

its perpendicular distance from the fuselage centerline plane. (It is a measurement of width.)

BRP

Body (Fuselage) Reference Plane. A plane that is perpendicular to the BBL plane and goes through BWL 208.10, the

top of the main deck floor beams.

BWL or WL

Body (Fuselage) Waterline. A plane that is perpendicular to the BBL plane, parallel to the fuselage centerline. It is

measured from a parallel imaginary plane, BWL 0.00, 148.5 inches below the lowest fuselage surface.

LBL

Left Buttock Line

RBL

Right Buttock Line

12




Figure 2

13




PRINCIPAL DIMENSIONS AND AREAS General

Dimensions are included for the wing, ailerons, flaps, horizontal stabilizer surfaces, vertical stabilizer surfaces and

body. Areas are included for the wing and stabilizer surfaces.

Dimensions Overall Airplane

- Length -- 109 feet-7 inches (737-300)



- Width -- 94 feet-10 inches

-Height (vertical stabilizer tip, top of the fairing to the ground) – 36 feet-6 inches

Fuselage

Height of the body reference plane (top of the floor beam WL 208.10).

Above the ground at the main gear -- 102.10 inches.

Height (constant cross section)

- Above the body reference plane -- 98.4 inches

- Below the body reference plane -- 59.60 inches

- Height to the centerline of the windows above the body reference plane

-- 38 inches

- Length -- 1267 inches (737-300)

- Length -- 1387 inches (737-400)

- Length -- 1173 inches (737-500)

Areas

Wing (basic) -- 980.0 square feet

Horizontal Stabilizer Surfaces (total, with the area in the fuselage) – 545 square feet

Vertical Stabilizer Surfaces (total) -- 370 square feet

14




Figure 3

B737-300

15




Figure 4

B737-400

16




Figure 5

B737-500

17




LIFTING & SHORING

JACKING

JACKING POINTS

The airplane has three main jack points and four auxiliary jacking points. The main points are wing jacking points A and B

and aft body jacking point C. The four auxiliary points are forward body jacking point D and three landing gear points, E

(nose) and F (Main Landing Gear). The airplane may be jacked at any gross weight provided the maximum load of any

jacking point is not exceeded. If the airplane is supported entirely by the three main jacks and the stabilizing jack at point D,

the maximum jacking weight of the airplane must not be exceeded.

Maximum jacking weight for the basic

- 737-300 is 43,092 kg (95,000 pounds);

- the 737-400 is 49,896 kg (110,000 pounds)

- and the 737-500 is 40,824 kg (90,000 pounds).

Axle jacking points E and F provide the means for changing two flat tires on the same axle up to maximum gross taxi weight.

Landing gear jack points are integral 3/4 inch spherical radius pads under main and nose gear axles.

The jacking points on the wing and body include special provisions for the attachment of bolt-on type jack adapters provided

with 3/4 inch spherical radius pads. To minimize the vertical lift during the jacking operation, main and nose gear shock strut

restrainers which lock the oleos in a de-pressurized and compressed condition may be used if gear retraction is not the

reason for jacking.

CAUTION: DO NOT LIFT THE AIRPLANE ON JACKS IN WINDS MORE THAN 35 KNOTS. IF YOU DO NOT OBEY

THESE INSTRUCTIONS DAMAGE TO THE AIRPLANE CAN OCCUR.

18




FIGURE 6

Jack Point Locations

19




TOWING & TAXIING

TOWING

TOWING AND TAXIING CLEARANCES

The airplane is normally towed or pushed by a tow bar attached to the nose gear. Maximum normal towing turning limits are

indicated by red stripes on the nose gear doors.

Maximum tow bar movement 78 either side. Tip clearances require special care during the turn. Brakes should not be used

during turns except in emergencies. Airplane should be moving before turning the nose wheel. Airplane nose wheel should

be fore and aft prior to parking.

20




FIGURE 7

21




POWER PLANT AND INLET DANGER AREAS

The wing-mounted engines require that the ground personnel be aware of the danger areas. The engine inlet efficiently

directs air into the engine.

The characteristics of jet engine operation require extreme care to prevent injury to personnel and/or damage to equipment.

An operating engine consumes large quantities of air and is capable of sucking large objects into the inlet including

humans. The exhaust of an operating engine has a velocity capable of overturning work stands, carts and at high engine

power can easily pick up humans. Also the noise of the operating engine can be harmful to the human hearing system.

Numerous incidents have been reported including injury to personnel by jet engines. One incident has resulted in a fatality.

The powerplant danger areas are the air inlet and exhaust from the fan and core sections of the engine. All these sections

provide hazards due to high air velocity and generated noise.

Operation

A typical engine inlet hazard area extends fan shaped forward from the inlet and aft from the inlet lip to the forward end of

the cowl panels. When the engine is operating above idle thrust the hazard area extends further forward from the inlet and

further aft of the nose cowl inlet lip. Personnel working on the engine aft of the inlet should take special care to strictly avoid

this hazard area.

WARNING: DURING GROUND RUNNING OPERATION THE ENGINE IS CAPABLE OF DEVELOPING ENOUGH

SUCTION AT THE INLET TO PULL A PERSON UP TO OR INTO THE DUCT WITH POSSIBLE FATAL RESULTS.

THEREFORE, WHEN APPROACHING ANY JET ENGINE, PRECAUTIONS MUST BE TAKEN TO KEEP CLEAR OF ALL

INLET AIR STREAM. THE SUCTION NEAR THE INLET CAN ALSO PULL HATS, GLASSES, LOOSE CLOTHING AND

WIPERAGS FROM POCKETS INTO THE ENGINE. ANY LOOSE ARTICLES MUST BE MADE SECURE OR REMOVED

BEFORE WORKING AROUND THE ENGINE.

22




FIGURE 8

Inlet and Exhaust Dangers Areas

23




FIGURE 9

Inlet and Exhaust Dangers Areas

24




WARNING PLACARDS

Warning

The danger areas associated with a running engine are identified by placards. The placards are located on each side of the

nacelle near the fan exhaust. The warning placard consists of a stripe, a silhouette of the engine indicating inlet and exhaust

danger areas, an international ―NO ENTRY TO PERSONNEL‖ sign and a warning text. The color of the placard is red.

25




FIGURE 10

Warning Placards

26




ATA 53 FUSELAGE

53-00 GENERAL

FUSELAGE GENERAL DESCRIPTION

Purpose

The fuselage is a structurally sound and aerodynamically contoured body which supports the wings, stabilizers and

landing gear. Most of it is pressurized for the coverage of payload.

System Description

A typical section through the fuselage consists of an upper and a lower oval which intersect approximately at the floor

level. At the intersection, the fuselage is reinforced by transverse floor beams. Above this floor structure, which extends

from the front pressure bulkhead at Body Station 178 to the rear pressure bulkhead at Body Station 1016, the upper

lobe of the fuselage encloses the cabin and is basically a continuous shell, with cutouts in the skin for doors and

windows. Below the floor the continuity of the lower lobe, which encloses the cargo compartments, is interrupted by

several major structural features: the nose landing gear wheel well, the cavity for the center wing box, and the main

landing gear wheel well. Aft of the rear pressure bulkhead, the floor is discontinued and this section of the fuselage, which

tapers towards its aft end, supports the vertical fin, the horizontal stabilizer, and contains a compartment for the APU.

27




B737-300

Figure 11

28




FUSELAGE GENERAL DESCRIPTION

General

Special design features maintain structural continuity between Body Stations 540 and 727 where the cavities for the center

wing box and the main landing gear interrupt the lower half of the basically tubular fuselage. A keel beam connects the

bottom of the fuselage frame at Station 540 with the bottom of the frame at Station 664 and passes below the center wing

box. The fuselage is divided into production or manufacturing sections, these being:

- Section 41 from STA 130 to STA 360



-Section 48 from STA 1016 to STA 1217

The fuselage is manufactured in four body sections connected by production or manufacturing breaks to form a complete

integral structure. The forward three sections form the pressurized shell of the fuselage and enclose the crew, passenger,

and cargo accommodations. The main frame includes frames, bulkheads, formers, longerons, stringers, keel beam and

frames around openings. Each frame is a zee-section circumferential member, with increased web depth at floor level.

The frames are generally spaced at twenty-inch intervals along the fuselage aft of the flight deck.

The bulkhead at Body Station 178 is the forward end of the pressure cabin and is composed of four vertical beams and a

flat pressure web which the beams divide into small panels.

At Body Station 227.8 a frame, with a web extending across the lower part of it, forms the forward wall of the nose landing

gear wheel well. At Body Station 294.5 a frame, with a web extending across the lower part of it, forms the aft

wall of the nose landing gear wheel well.

At Body Station 360, a bulkhead extends across the fuselage from floor level and down to form the forward wall of the

forward cargo compartment.

At Body Station 500D, a bulkhead extends across the fuselage from floor level and down. This bulkhead serves as the aft

wall of the forward cargo compartment.

29




-continued-

At Body Station 664, a bulkhead extends across the fuselage from floor level and down. This bulkhead serves as the aft spar

of the center wing box and the forward wall of the main landing gear wheel well.

At Body Station 727, a bulkhead extends across the fuselage from floor level and down. This bulkhead serves as the aft wall

of the main landing gear wheel well and the forward wall of the aft cargo compartment.

The pressure bulkhead at Body Station 1016 is a curved web extending aft like a dome in the vertical plane. The web is

reinforced with radii stringers all originating at the center of the web. The web forms the aft end of the pressurized

cabin. The vertical fin front spar attach fittings are at the top of the fuselage at Body Station 1016.

30




B737-400

Figure 12

31




FUSELAGE GENERAL DESCRIPTION (CONT.)

General (cont.)

The bulkhead at Body Station 1088 incorporates the vertical fin rear spar attach fittings. A rectangular cutout in the web

allows the forward part of the horizontal stabilizer center section truss to protrude through it. The horizontal stabilizer

jackscrew mechanism is attached to the forward side of the bulkhead web.

A non-retractable tail skid is located between Body Stations 1064 and 1088. (737-400) The bulkhead at Body Station 1156

incorporates the horizontal stabilizer center section truss hinge joints. Elevator control mechanisms are attached to the aft

side of the bulkhead. The lower part of the bulkhead is cut away to allow for the APU exhaust pipe.

The fuselage stringers, which start at Body Station 259.5, are hat-section members along the entire fuselage. The continuity

of the stringers is maintained across the production joints in the fuselage structure by terminating the stringers on each

section at a fitting which is attached to the production joint frame. The keel beams comprise the beam between the main

landing gear wheel wells and the beam which passes beneath the center wing box. The beam between the wheel wells is a

reinforced box structure which carries pressurization loads originating on the sealed floor structure across the wheel well

area. Both of the beams carry the bending loads acting along the lower fuselage across the cavities for the center wing box

and the wheel well.

The fuselage skin varies in thickness according to the loads it must bear in any given area, and it is designed with fail-safe

features to ensure alternate load paths in the event of a local failure. The thickest skin panels are those over the area where

the lower fuselage is cut away to accommodate the wing and the main landing gear wheel well. In this area the skin panels

are machined from thick sheets. Many of the skin panels are attached to each other by bonded longitudinal lap joints, which

provide pressure seals in addition to being structural joints. Circumferential skin splices exist aft of the control cabin, at the

front spar bulkhead, at the bulkhead aft of the wheel well, and at the aft pressure bulkhead. The skin is reinforced by means

of doublers bonded to the inside of the outer skin. These doublers function as tear stoppers by forming a complete, integral

fail-safe, circumferential and longitudinal ―waffle‖ grid.

32




-continued-

The fuselage structure around all door openings is reinforced to ensure adequate distribution of fuselage loads around the

opening. The passenger window openings are reinforced by doublers forming part of the inner waffled skin. The control cabin

window frames are reinforced fabrications of extruded sections.

Access panels are provided in the fuselage, refer to the Maintenance Manual, Chapter 12, Section 31, for location and

identification. Two overwing emergency exit doors are installed on each side of the fuselage. One between Body Stations

578 and 601, the other door between Body Stations 616 and 639. (737-400)

A horizontal beam extends along each side of the fuselage level with the top of the floor. These beams are known as the

crease beams because they are attached to the fuselage skin at the ―crease‖ formed by the intersection between the upper

and lower lobes of the fuselage cross-section.

The materials used for fuselage construction are:

- Frames - Aluminum Alloy 2024 and 7075

- Stringers - Aluminum Alloy 7075

- Keel beam - Aluminum Alloy 7075

- Skins - Aluminum Alloy 2024

- Floor beams - Aluminum Alloy 7075

- Radar Enclosure, APU tailcone - Fiberglass and Honeycomb

- APU exhaust area - Titanium

33




ATA 57 WINGS

57-00 GENERAL

WINGS GENERAL DESCRIPTION

The structure of the wing supports the two wing mounted powerplants, the

flight controls and provides a lifting airfoil for the airframe. The wing also supports the main landing gear beams.

The structure of the wing between left and right tips consists of the left, center and the right wing boxes. The left and right

wing boxes are cantilevered from the center wing box which is enclosed within the fuselage. The thickness and chord of

each wing tapers down toward the tip and in plain view, both wings sweep back from the center wing box. The landing

gear support beam is attached at its outboard end to the rear face of the wing rear spar. Short struts underneath each

wing support the two powerplants.

Flight controls consist of slats, flaps, ailerons and spoilers and are attached at front and rear spars.

Vortex generators are installed on the upper wing surface.

The wing boxes and the center wing box consists of upper and lower skin panels, ribs and front and rear spars. The skin

panels are reinforced by spanwise stringers, the spars by vertical stiffeners, and the wing boxes by a series of chordwise

ribs. The center wing box is reinforced by spanwise beams. Access panels are provided in the wing. The landing gear

support beams are two-piece I-section forgings bonded and bolted together and connected at their outboard ends to the

left and right wing rear spars and at their inboard ends to the left and right sides of the fuselage.

34




Leading Edge Slats

Three leading edge slats are installed on each wing outboard of the engine. The slats consist of ribs attached to a beam,

inner and outer skins and a trailing edge. A void between the inner and outer skins provides a path for thermal anti-icing.

Leading Edge Flaps

Two leading edge flaps are installed on each wing. Each flap is a machined casting containing integral ribs and stiffeners.

Trailing Edge Flaps

The inboard and outboard trailing edge flaps consist of a midflap, a foreflap, and an aftflap.

The inboard midflap consists of ribs, three spars, honeycomb trailing edge and skins.

The outboard midflap consists of ribs, two spars, a trailing edge beam, two honeycomb trailing edge panels and skins.

The foreflap is a monospar structure with a honeycomb trailing edge panel and skins.

The aftflap is also a monospar structure with a honeycomb trailing edge panel and skins.

Aileron

Each aileron is a frame structure consisting of leading and trailing edge spars, ribs and skin. An aileron tab is attached to

the rear spar of the aileron by four hinges. Ailerons together with flight spoilers provide roll control of the aircraft.

Spoilers

The spoiler panels are of graphite/epoxy construction. They are constructed with upper and lower skins and with a

honeycomb core. A continuous phenolic rubstrip is bonded to the lower surface at the trailing edge.

Attach Fittings - Wing Terminal Fitting

The wing terminal fitting is a heavy three-flanged forging. There are four of these fittings, the two forward ones and the two

aft ones. The flanges of the fitting act as a means of connection between the wing boxes and the center wing box. The wing

box to center wing box connection is accomplished by the use of the three flanges of the wing terminal fitting. The places of

connection are at the four corners of the center wing box where three main members join: a wing box spar, a center wing

box spar, and a wing root rib. At any one corner of the center wing box, the two spars and the wing root rib are attached to

the three flanges of the fitting.

35




-continued-

Attach Fittings - Flight Controls

The aileron attachment fittings consist of hinge and actuation mechanism fittings and these are mounted on the aft side of

the rear spar and to structure mounted on that spar. The trailing edge flap attachment fittings on each wing consist

primarily of two pairs of flaptracks, one pair for each flap assembly.

Attach Fittings - Flight Controls (Cont)

The leading edge flap attachment fittings consist of hinge fittings mounted along the forward edge of the leading edge

structure. The leading edge slat attachment fittings consist of brackets which support the guide rollers and the actuators,

all of which are attached to the forward face of the wing front spar. The spoiler attachment fittings consist of hinge fittings

and the fittings which support the actuation mechanisms. The fittings associated with the outboard set of spoilers are

mounted on the aft face of the wing rear spar and those for the inboard spoilers are on the aft face of the wing rear spar

and landing gear support beam.

The wing is divided into reference planes measured in inches. This provides a means of identifying the location of

components or particular points. Two reference planes are used for the wing.

36




WSTA - Wing Station

A plane perpendicular to the wing chord plane, and normal to the rear

spar, measured from the intersection of the wing leading edge line extension

and Wing Buttock Line 0.00.

WBL - Wing Buttock Line

A plane perpendicular to the wing chord plane and parallel to the body

buttock line. It is measured from intersection of wing chord plane and

Body Buttock Line 0.00.

37




Materials

The materials used for construction of the wings are:

WING CENTER SECTION

- Beams - Aluminum Alloy 7178

- Stringers - Aluminum Alloy 2024

WING

- Spars - Aluminum Alloy 2024 and 7178

- Ribs — Aluminum Alloy 7075

- Upper Skin and Stringers - Aluminum Alloy 7150

- Lower Skin and Stringers Aluminum Alloy 2324 and 2224

VORTEX GENERATORS

- Aluminum Alloy 2024

LEADING EDGE SLATS


LEADING EDGE FLAPS

- Aluminum Alloy A356 (Casting)

TRAILING EDGE FLAPS

- Aluminum Alloy 2024 and Honeycomb

AILERON

- Graphite/Epoxy and Honeycomb

SPOILERS

- Graphite/Epoxy and Honeycomb

LANDING GEAR BEAM


38




FIGURE 13

39




ATA 54 NACELLES / PYLONS

54-00 GENERAL

STRUT

The engine struts are attached to the wing front spar and provide a structurally sound attachment point for the two airframe

powerplants.

The two engine struts are cantilevered from the front spar of each wing and are structurally similar but not interchangeable.

The basic structure consists of a torque box attached to the wing structure by linkages and braces with fuse pins. Engine

attachment points are located at forward and mid sections of the torque box. Between the two engine attachments are two

thrust links connecting the torque box to the engine. On the bottom section of the torque box is the engine firewall. Forward

of the torque box is the fan cowl support beam and forward fairing. Behind the torque box is the aft fairing, and the trailing

edge flap track fairing. Access panels are provided in the strut. Refer to the Maintenance Manual, Chapter 12, Section 31

for location and identification.

40




Materials

The materials used for strut construction are:

TORQUE BOX

Aluminum Alloy 7075 and 2024

FIREWALL

Stainless Steel

FAN COWL SUPPORT BEAM SKIN AND FORWARD FAIRING

Graphite/Epoxy composite and Kevlar

AFT FAIRING

Aluminum Alloy and Aluminum Honeycomb

41




FIGURE 14

42




NACELLE

The nacelle provides an aerodynamically sound enclosure for the strut mounted engines. It provides for smooth airflow

around and into each engine while causing a minimum amount of drag. It also protects the components mounted on the

engine from physical damage from outside sources.

The nacelle, which encloses the engine, consists of the inlet cowl, fan cowls, thrust reverser, and trailing edge fairing.

The cowlings and thrust reverser fairing consist of frames and skins. The interior skin of the inlet cowl is treated with

sound suppression material.

The nacelle is divided into reference planes measured in inches. This provides a means of identifying the location of

components of particular points. Two reference planes are used for the nacelle.

NAC WL Nacelle Waterline

A plane 10 38’ down from the wing chord plane.

NAC STA Nacelle Station

Distance measured parallel to nacelle CL from a point 120.47 inches forward of the nacelle.

43




Materials

Materials used in construction of the nacelles are:

INLET COWL

Aluminum Alloy 2024, Fiberglass and Aluminum Honeycomb

FAN COWLS

Kevlar, Graphite/Epoxy and Honeycomb

THRUST REVERSER FAIRING

Graphite/Epoxy and Aluminum Honeycomb

TRAILING EDGE FAIRING

Kevlar Honeycomb - Upper Stainless Steel Cap

44




FIGURE 15

45




ATA 55 STABILIZER

55-10 HORIZONTAL STABILIZER

GENERAL DESCRIPTION

The horizontal stabilizer provides aerodynamic pitch trim and control of the airplane.

The horizontal stabilizer assembly consists of left and right outboard sections attached to a center section truss located

within the fuselage. The stabilizer pivoted on two hinge joints attached to a bulkhead in the fuselage. The angle of attack

is adjusted by means of an electrically driven or manually operated ballnut and jackscrew attached to the forward side of

the center section truss. An aerodynamic seal fills the gap between the stabilizer left and right outboard sections and the

fuselage. A sliding plate seal is located at points where the front and rear spars pass into the fuselage. A leading edge is

attached to the front spar. The trailing edge and elevator hinge structure is attached at the rear spar. Access panels are

provided in the horizontal stabilize refer to the Maintenance Manual, Chapter 12, Section 31 for location and

identification.

The front and rear spars, the ribs and the skin of the horizontal stabilizer outboard sections together with the center

section truss form a beam which is the main structural member of the stabilizer. Attachment of the outboard sections

and the center section is at the front and rear spars only, with no structural tie between the outboard section skins and

the center section.

46




-continued-

The structure aft of the rear spar consists of ribs which incorporate hinge bearings for the elevator. The upper and lower

surfaces of the area between the rear spar and the elevator hinge bearings are covered by skin panels attached to the

ribs. Some of the skin panels are removable for maintenance purposes. The gimbals surrounding the jackscrew ballnut are

supported by a rigidly built-up framework of members on the forward face of the center section truss front spar. The basic

structure of the elevator is dual spar at the inboard end and monospar at the outboard end, with all areas reinforced with

ribs. The elevators are attached to hinge ribs extending aft from the rear spar of the stabilizer by elevator hinges on the

front spar of the elevator. The elevator balance panels project forward of the hinge line and are housed in the space

between the hinge ribs on the stabilizer rear spar. An elevator tab is attached to the rear spar of the elevator.

Empennage flight control surface attach fittings are aluminum alloy forgings. The fittings on which the horizontal stabilizer

outboard sections are mounted to the center section truss are at the inboard ends of the center section truss front and rear

spars. The fittings, incorporating the hinges on which the center section truss pivots are mounted on the aft face of the

truss rear spar and the bulkhead at Body Station 1156. Fittings associated with the elevators include elevator and tab

hinge fittings and fittings for the actuation mechanisms. The horizontal stabilizer is divided into reference planes measured

in inches. This provides a means of identifying the location of components or particular points.

47




THREE REFERENCE PLANES ARE USED FOR HORIZONTAL STABILIZER

STAB STA Horizontal Stabilizer Station. A plane perpendicular to the stabilizer chord plane and normal to the stabilizer rear

spar, measured from Stabilizer Station 0.000, the intersection of the leading edge line extension and Body Buttock

Line 0.000.

STAB LE STA Horizontal Stabilizer Leading Edge Station. A plane perpendicular to the horizontal stabilizer leading edge,

measured from the Stabilizer Leading Edge Station 0.00, the intersection of the leading edge line extension and

Body Buttock Line 0.00.

ELEV STA Elevator Station. A plane perpendicular to the elevator hinge centerline measured from the intersection of elevator

hinge centerline and Body Buttock Line 0.00.

48




FIGURE 16

49




Materials

Materials used in construction of the horizontal stabilizer are:

STABILIZER

Spars and Ribs - Aluminum Alloy 7075

Skin - Aluminum Alloy 2024

Skin aft of rear spar - Kevlar and Honeycomb

ELEVATOR

Spar and Ribs - Aluminum Alloy 2024

Skin - Graphite/Epoxy

TAB

Spar - Aluminum Alloy 2024

Skin - Graphite/Epoxy

STABILIZER TRUSS

Aluminum Alloy - 7075

50




FIGURE 17

51




55-30 VERTICAL STABILIZER

GENERAL DESCRIPTION

The vertical stabilizer gives stability in the yaw axis for the airplane and provides for directional control with the use of a

rudder during takeoff and landing and for trim during cruise conditions.

The vertical stabilizer (fin) is attached to body Section 48 at two points. The leading edge is detachable. The dorsal fin is

not structurally connected to the main vertical fin. The fittings on which the vertical fin is mounted are at Body Stations

1016 and 1088 and Fin Waterline 0.

The front and rear spars, the ribs and the skin of the vertical fin form a beam which is the main structural member of the

fin. The structure aft of the rear spar consists of ribs which incorporate hinge bearings for the rudder. The left and right

surfaces of the area between the rear spar and the rudder hinge bearings are covered by skin panels attached to the

ribs to form a trailing edge fairing. A removable leading edge structure is attached to the forward side of the fin front

spar. A fairing is attached at the top of the fin. Access panels are provided in the vertical stabilizer, refer to the

Maintenance Manual, Chapter 12, Section 31 for location and identification.

The rudder structure consists of a complete front spar and a partial rear spar, chordwise ribs, and skin panels. The

rudder has hinge fittings forward of its front spar. Forward of the rudder front spars are leading edge fairings and nose

sections, which are housed within the vertical fin trailing edge fairing. In one nose section is located a rudder balance

weight. The vertical stabilizer is divided into reference planes measured in inches. This provides a means of identifying

the location of components or particular points.

52




Four reference planes are used for the vertical stabilizer.

FIN STA - Vertical Stabilizer Station

The plane perpendicular to the center line of the vertical stabilizer rear spar, measured from Fin

Station 0.00, the intersection of the leading edge line extension and Fin Waterline 0.00.

FIN WL - Vertical Stabilizer Waterline

A horizontal plane measured parallel to a Body Waterline. Fin Waterline 0.00 is Body Waterline

300.50.

FIN LE STA - Vertical Stabilizer Leading Edge Station

A plane perpendicular to the vertical stabilizer leading edge, measured from the Fin Leading Edge

Station 0.00, the intersection of the leading edge line extension and Fin Waterline 0.00.

RUD STA - Rudder Station

A plane perpendicular to the rudder hinge centerline, measured from Rudder Station 0.00, the

intersection of the rudder hinge centerline and Fin Waterline 0.00.

53




Materials

Materials used in construction of the vertical stabilizer are:

STABILIZER

Spars and Ribs - Aluminum Alloy 7075

Skin - Aluminum Alloy 2024

Skin aft of rear spar - Kevlar and Honeycomb

DORSAL

Ribs - Aluminum Alloy 2024

Skin - Graphite/Epoxy and Honeycomb

RUDDER

Spar and Ribs - Aluminum Alloy 2024

Skin - Graphite/Epoxy and Honeycomb

54




FIGURE 18

55




ATA 52 DOORS

52-00 GENERAL

INTRODUCTION

The purpose of the doors is to permit entry to or exit from the various airplane compartment and areas.

Entry Doors:

- Provide for entry and exit for passengers and crew members. Located on the left side, forward and aft.

Galley Service Doors:

- Located forward and aft on the right side, they are normally used for servicing the galleys. They also serve as

emergency exits.

Emergency Exits:

- The overwing emergency hatches are available as emergency exits on both sides.

Cargo Compartment Doors:

- Provide access to the cargo compartments; located forward and aft of the wing on the right side.

External Service Doors:

- These doors are used by ground personnel for maintenance and servicing. The two doors in the pressurized portion

are located in the lower fuselage forward and aft of the nose gear.

The flight compartment door is a secure door controlled by the flight crew. It provides positive separation between the

flight compartment and passenger compartment.

56




FIGURE 19

57




FIGURE 20

58




52-10 PASSENGER / CREW

ENTRY DOOR

The purpose of the entry doors is to provide the primary entrance and exit for the passengers and flight crew.

The entry doors are located on the left side of the airplane at the fore and aft ends of the passenger compartment.

The forward entry door is 34 inches wide and 72 inches high, the aft entry door is 30 inches wide and 72 inches

high. Both are inward - outward opening plugtype doors. An upper and lower hinge assembly support the door on

its forward edge; the doors may be closed or opened from inside or outside the airplane.

The door is opened by manually operating the centrally located handle. This action causes the internal

mechanism to release the latches, folds the gates inward, and moves the door to its most inward position. The

door is manually swung through the door opening and stowed in the open position forward of the opening.

59




FIGURE 21

60




FIGURE 22

61




ENTRY DOOR MECHANISM

The entry door mechanism consists of several assemblies that accomplish the following functions:

Handle Mechanism:

- This mechanism, through a duplex arm, converts the rotary motion of the handles to a push-pull motion of two cranks.

One crank actuates the latches, and upper and lower gates during initial handle rotation. The other crank moves the

forward edge of the door inward to its open position during further rotation.

Door stops and latching assembly:

- These devices transmit pressure loads from the door to body structure, and latch the door in the closed position.

Centering Guide:

- A pin on the aft edge of the door slides into a guide track on the frame to align the stops and latches.

Lower Hinge:

- A rigid hinge arm is attached to the lower end of both the body and door torque tube assemblies. A hydraulic snubber

impedes door movement at its travel extremities.

Upper Hinge:

- A rigid hinge arm is attached to the body and door torque tube assembly.

A guide arm parallel to the hinge arm rides in an ―S‖ shaped track to control the door rotation about its torque tube.

Spring Assist Torque Tube (counterbalance assembly):

- The upper and lower hinge arms are attached to a vertical, body mounted torque tube to support the door when it is

open. Torsion springs around this torque tube provide opening and closing assistance.

62




FIGURE 23

63




FIGURE 24

64




FIGURE 25

65




FIGURE 26

66




FORWARD ENTRY DOOR OPERATION

Two cam rollers are moved by a cam plate that is rotated by the door handle action. This action provides the force

required to operate the latches, the upper and lower gates and orient the door through the opening by the torque tube.

The camming action is transmitted by pushrods to the latches, torque tube and end gates by control rods.

The aft entry door operates in the identical manner.

67




FIGURE 27

68




CAM PLATE OPERATION

Unlatching

Initial rotation of the cam plate transmits angular movement to the latching crank assembly. The control rods at each end

of the latching crank, turn the latch rods and withdraw the latch rollers. The latch rods also operate the control rods

attached to the upper and lower gates, causing them to fold inward. These control rods all have adjustable end bearings

for latch and gate rigging. During this initial movement, the cocking crank roller is riding on a surface of constant radius

from the cam plate pivot center; no angular movement is imparted to the cocking crank assembly.

Cocking

Rotation of the cam plate to its full travel transmits angular movement to the cocking crank assembly. The cocking crank

operates the push rod connected to the torque tube. An adjustable end bearing on the cocking crank pushrod moves the

door laterally for latch engagement rigging. Movement of the pushrod is resisted by the torque tube, causing the door to

rotate and pivot about the torque tube axis.

Opening

The door is swung forward through the opening manually until the door is approximately parallel with the airplane exterior.

The door will lock in this position

69




FIGURE 28

70




UPPER HINGE / GUIDE ARM GEOMETRY

Operation

As the cam plate is rotated by the handle, the cocking crank pushrod rotates the door torque tube and upper hinge arm

counterclockwise (viewed from above). This moves the door inward. The guide arm at the upper hinge, riding in the ―S‖

shapes cam track, changes the hinge geometry causing the door to rotate about the door torque tube to the cocked

position. From the cocked position, the door is manually swung to its fully open position pivoting about the body torque

tube. The guide arm causes the door to also pivot about the door torque tube so that it is parallel to the fuselage when fully

open. The guide arm end bearing is adjustable to fair the door with the fuselage.

71




FIGURE 29

72




52-40 SERVICE

GALLEY SERVICE DOOR

The purpose of the galley service doors is to provide an entrance for servicing the airplane galleys on the right side of the

airplane. They may also be used as a secondary entrance and exit for passengers and crew.

The galley service doors are located on the right side of the airplane at the fore and aft ends of the passenger

compartment.

The galley service doors are 30 inches wide and 65 inches high. Except for the size, the physical description and features

of the galley service doors are the same as the entry doors.

The operation of the galley service doors is identical to the entry doors.

73




FIGURE 30

74




LOWER NOSE COMPARTMENT ACCESS DOOR

The purpose of the lower nose compartment access door is to permit access to the compartment below the flight

compartment. Many flight control cables and brake accessories pass through this area.

The lower nose compartment access door is located in the bottom of the fuselage forward of the nose wheel well and aft of

the radome.

The door is an inward opening, plug-type door that can be opened only from outside the airplane. Two hinge arms extend

aft from the door to hinge fittings on the forward face of the nose wheel well forward bulkhead. The door latching

mechanism consists of a latch pin which protrudes through the forward edge of the door to engage a hole in the fuselage

structure.

The door is opened from outside the airplane by pushing the trigger in the door handle; the handle springs out from its flush

position. Rotating the handle counterclockwise retracts the latch pin and allows the door to be hinged upward. When the

door is closed, a clockwise rotation of the handle pushes the latch pin into the structure forward of the door. The handle

must be pushed back flush with the door skin.

75




FIGURE 31

76




ELECTRONIC EQUIPMENT COMPARTMENT ACCESS DOOR

The purpose of the electronic equipment compartment access door is to permit access into the compartment containing the

avionics, the battery, and the dc external power connection.

The electronic equipment compartment door is located aft of the nose wheel well and forward of the wings in the bottom of

the fuselage.

The electronic equipment compartment external access door is a plug-type, inward opening, sliding door on the bottom side

of the fuselage aft of the nose wheel well. The door is operated from outside the fuselage and is included in the door

warning system, sharing a common warning light in the control cabin with the lower nose compartment access door. The

door tracks inside the fuselage guide the door inward, upward, and to the right. The door has an alclad frame and skin

construction. A continuous seal around the periphery of the door prevents loss of cabin air when the airplane is in flight.

Four latch pins transmit pressurization loads from the door to the fuselage structure. The stop fittings on the door and the

door lock fittings on the structure will transmit the pressurization loads if the door is accidentally not latched. Rollers at the

end of an angle on the door engage with roller guides on the fuselage to keep the door in position.

Latch Mechanism

The door latching mechanism has a latch stop and lock fitting on each side of the door. The latch pins are operated through

a common rack and pinion mechanism. The inner end of each pin is in the form of a rack and all four racks engage with

a pinion on the central actuator shaft. The shaft has an outer handle to operate the door from outside the airplane.

Door Tracks

The door tracks are inclined upward and outboard from door opening. The door tracks are attached to the electronic rack

supports and the electronic rack stanchions.

77




Top and Bottom Web Assembly

The bottom web holds the door when you move it up the tracks. Flexible leaf-spring brackets attach the bottom web to the

door. The top and bottom webs have eight rollers which keep the webs between the door tracks. The bottom web retracts

into the top web as the door moves to its stowed position.

Uplatch (if installed)

An uplatch is on the inner right side of the door. The uplatch holds the door to the bottom web as it is retracted. The uplatch

engages the latch pin after you move the door up and to the right 1/2 to 1 inch. A lever disconnects the uplatch from the

bottom web as you close the door. If you let the door roll to the left when it is opened, the door will disengage from the

tracks. A cable assembly with a spring in the door decreases the rate of fall of the door after the uplatch releases the door. A

guard over the striker prevents accidental release of the uplatch.

Spring Spool Assembly

The spring spool assembly helps to retract the door and holds the door in the open position. The assembly is attached to

the fuselage at the end of the tracks.

Airplane with an Uplatch

One end of the flat spring is attached to the bottom web.

Airplane with a Trolley

One end of the flat spring is attached to a hinge on the trolley.

Trolly if installed

The trolley moves in a track to support the right side of the door and direct it as it moves to its stowed position.

78




FIGURE 32

79




ELECTRONIC EQUIPMENT COMPARTMENT ACCESS DOOR

(CONT)

Operation

OPEN THE DOOR FROM OUTSIDE THE AIRPLANE:

Push the trigger in the outer handle, to get access to the handle.

-A spring will push the handle from its flush position.

Turn the handle counterclockwise.

-The four latch pins will retract into the door.

-The door warning lights in the control cabin will come on.

Push the door up and to the right.

- The right side of the door will pivot about the track attach brackets on the left side of the door.

Airplanes with an Uplatch

-The uplatch, on the right side of door, engages the latch pin on bottom web.

Move the door up the track to its stowed position.

- The door will move easily with help from the assist spring.

CLOSE THE DOOR FROM OUTSIDE THE AIRPLANE:

Pull the door down the tracks with the handle.

Airplane with an Uplatch

-At the bottom of the track, the lever will disengage the uplatch, and release the door from the bottom web.

Make sure the door is seated correctly.

Pull down on the door handle to compress the door pressure seal and turn

the handle clockwise.

- The four latch pins will lock the door in its closed position.

-The door warning lights in the control cabin will go off.

Push the handle up to its flush position.

80




FIGURE 33

81




52-20 EMERGENCY EXIT

EMERGENCY EXIT HATCH

The purpose of the emergency exit hatch is to provide a means of exiting the passenger compartment in the event of an

emergency.

These identical hatches are located on each side of the fuselage at the overwing area.

82




FIGURE 34

83




EMERGENCY HATCH DETAILS

The hatches are 20 inches wide by 38 inches high and are classified as Type III emergency exits. The hatches are plug-

type and can be opened from inside or outside the airplane. Each hatch is supported by a lower pivot fitting which

engages a lower pivot hook on the sill of the opening. Two heel pads attached the hatch rest on the sill. The handle is an

integral casting formed with a pull- lever on the inside and a push-type panel on the outside. The lower end of the handle

is attached to a torque tube; on each end of the torque tube is a latch roller which engages the latch fittings attached to

the forward and aft frames of the hatch opening. Adjustable stop pins attached to the forward and aft edges of the hatch

contact stop fittings attached to the forward and aft frames of the hatch opening. The stops transmit the pressurization

loads on the hatch to the fuselage structure.

84




FIGURE 35

85




FIGURE 36

86




EMERGENCY EXIT HATCH OPERATION

Inside Removal

The hatch is opened from the inside by pulling down and in on the handhold pocket which is attached to the operating

handle. The action of the handle rotates the torque tube and turns the latch rollers. The latch rollers disengage from the

latch fittings and the top edge of the hatch moves inward.

Continuing to hold the upper handle, the lower handhold is grasped with the other hand and the hatch is pulled inward at

the top edge. The hatch is then lifted upwards and inwards away from the opening, disengaging the lower pivot fitting from

the lower pivot hook.

Outside Removal

The hatch is opened from the outside by pushing in on the panel at the top of the hatch and then pushing the hatch into

the airplane.

87




FIGURE 37

88




52-30 CARGO

CARGO COMPARTMENT DOORS

The purpose of the cargo compartment doors is to provide access to the forward and aft cargo compartments. The forward

cargo compartment door also permits access to the flight crew oxygen cylinder.

The cargo compartment doors are located on the right side of the airplane; the forward cargo compartment door is forward

of the wing and the aft cargo compartment is aft of the wing.

Both cargo compartment doors are plug-type, inward opening, manually operated, and hinged at the upper edge. Both

doors are the same in design and operation; however, they are not interchangeable. The forward door is 48 inches wide by

35 inches high and the aft door is 48 inches wide by 33 inches high.

Each door is hinged from the fuselage structure by two hinge arms on the upper edge. Pressurization loads are

transmitted to the fuselage by twelve stop fittings. Each door is equipped with a balance mechanism to counterbalance

the weight of the door. A snubber is installed between the hinge arms to restrain the free—fall of the door if the balance

mechanism cable fails.

Latch Mechanism

The door latching mechanism consists of two latching rollers, one at each end of a horizontal torque tube. The latching

rollers engage latch fittings attached to the fuselage. The torque tube is connected to the operating handle assembly.

The operating handle assembly has a handle on the inside of the door and a handle on the outside. The inside handle is

stationary but the outside handle is spring-loaded so that it retracts flush with the door when released after use.

89




Balance Mechanism

Balance Mechanism on airplanes with an uplatch,

- door balance is maintained by springs attached to the upper aft inner edge of the door between the inner web and outer

skin.

- The springs connect to a cable assembly wound on a cable drum mounted on the forward inner structure of the door. From

the cable drum, the cable runs over two pulleys mounted on the inner structure of the door and connects to an overhead

floor beam.

- The cable grooves in the cable drum have a decreasing radius in order to provide a constant tension in the cable system as

the door is opened and closed.

- The balance mechanism is arranged so that the springs are stretched when the door is closed. When the door is opened,

the springs contract to raise the door to or near the open latched position.

On airplanes with a counterbalance assembly,

- door balance is maintained by a spring-driven idler crank that drives a cam fixed to a cable drum.

- The springs, idler crank, cam and drum are all located in the counterbalance assembly mounted on the inner structure of

the door.

- From the drum the cable runs over a pulley mounted on the inner structure of the door and connects to an overhead floor

beam.

- The counterbalance mechanism is arranged so that the springs are compressed when the door is closed.

- When the door is opened the springs extend to drive the idler crank, cam and drum to raise the door.

90




FIGURE 38

Airplane with Uplatch

91




FIGURE 39

Airplane with Counterbalance

92




FIGURE 40

Airplane with Counterbalance

93




CARGO DOOR OPERATION

The door is opened from outside the airplane by pulling the door handle out of the recess and rotating the handle

counterclockwise. Rotation of the handle actuates a torque tube to withdraw the latch rollers from the latch fittings. As the

door swings inboard, under tension of the door balance mechanism, the door warning proximity switch is actuated to

energize the appropriate door warning light in the control cabin.

As soon as the door has moved clear of the latch fittings, the handle may be released. springs within the handle will cause

the handle to return to the normally locked and recessed position. With little manual effort, the door may be swung open to

the open latch position.

On airplanes with an uplatch,

- the door is latched open when the spring-loaded mechanical latch on the lower edge of the door engages with a fitting

under the fuselage floor structure.

On airplanes with counterbalance assembly,

-the idler crank engages a detent on the cam inside the counterbalance assembly to latch the door open.

The door may be opened from inside the airplane, using the nonretracting inner handle. In this case, the procedure is similar

except that rotation of the handle appears clockwise to the operator.

Access to the inside handle is obtained by pulling aside the cargo net which extends from the ceiling to the lower edge of the

door.

94




On airplanes with an uplatch,

- the door is closed by pulling on the lanyard to release the latch. The lanyard is adjacent to the cargo retaining net just

inside and forward of the door opening and is accessible to personnel standing on the ground.

- The lanyard design requires that the handle must be pulled outside the door opening before the latch will disengage.

- After the latch is disengaged, a continued pull on the lanyard brings the door down until the operating handle is within

reach. The handle is then lifted out of the recess. The lanyard is then released to return to normal position within the cargo

compartment.

- Counterclockwise rotation of the operating handle aligns the latch rollers with the latch fittings and allows the door to be

pulled down and latched by a clockwise rotation of the handle. This final movement engages both latch rollers in the fittings

and actuates the door warning proximity switch to de-energize the appropriate warning light in the control cabin. When the

door is thus closed and latched, the handle may be released.

On airplanes with counterbalance assembly,

- the door is closed by pulling on the lanyard to move the door down until the operating handle is within reach.

- The handle is then lifted from its recess and the lanyard is released. Counterclockwise rotation of the operating handle

aligns the latch rollers with the latch fittings and allows the door to be pulled down and latched movement engages both latch

rollers in the fittings and actuates the door warning proximity switch to de-energize the appropriate warning light in the

control cabin.

- When the door is thus closed and latched, the handle may be released.

95




FIGURE 41

96




FLIGHT COMPARTMENT DOOR EMERGENCY EXIT FEATURE

An emergency exit feature is provided which permits the release and removal of the two upper blowout panels from the door.

The removal of the two upper panels permits an emergency exit through the door. The emergency exit door release handle

is located on the forward side of the door between the two upper blowout panels. The release handle is grasped and pulled

forward. This movement of the handle operates a cable assembly and linkage which disengages retaining pins located on

each side of the handle at the door channel and allows the release handle to move forward.

The panels are then pulled forward of the door structure and allowed to drop. The panels are free of the door structure and

the emergency exit is available for use. The first observer’s seat can be released from stowed position and used as a step

when using the emergency exit in the door.

97




FIGURE 42

Control Cabin Door (Front Side)

98




FLIGHT COMPARTMENT DOOR LOCK

Power

The source of power for the electric feature of the flight compartment door lock is 28 volt dc bus No. 2.

Control

Control of the electric door lock is through a switch/light located on the aft P8 panel.

Operation

When the switch/light is illuminated, the door is unlocked. The door can be opened with a pull of 10 pounds, minimum.

When the switch/light is pressed, and the light extinguishes, the electric strike in the door frame is energized and the door is

locked.

Flight Compartment Doors are changed by new improved Flight Security Doors

within FAA regulative

99




FIGURE 43

100




DOOR LOCK OPERATION

Unlocked

When the door is unlocked, the striker will pivot out of the way when a force of 10 pounds is exerted to open the door from

the passenger compartment. From the flight compartment, the door may be opened by either pushing aft or turning the

knob.

Locked

When the switch/light on the P8 panel is pressed and the light extinguishes, the solenoid in the door frame is energized and

a shear pin is driven into a recess in the striker. The striker is now held rigid and the door is locked. The shear pin will break

if a force greater than 250 pounds is exerted. The door can be opened without breaking the shear pin by retracting the latch

bolt in the door with a key or turning the door knob. The key must be used when opening the door from the passenger

compartment and the door is locked. From the flight compartment, the latch bolt can be withdrawn by turning the door knob.

In the event of a power failure, the solenoid will de-energize and the shear pin will drop from the recess in the striker. The

door will be unlocked and can be opened in the normal manner.

101




FIGURE 44

102




FLIGHT COMPARTMENT DOOR EMERGENCY EXIT FEATURE

Operation

An emergency exit feature is provided which permits the release and removal of the two upper blowout panels from the door.

The removal of the two upper panels permits an emergency exit through the door. The emergency exit door release handle

is located on the forward side of the door between the two upper blowout panels. The release handle is grasped and pulled

forward. This movement of the handle operates a cable assembly and linkage which disengages retaining pins located on

each side of the handle at the door channel and allows the release handle to move forward.

The panels are then pulled forward of the door structure and allowed to drop. The panels are free of the door structure and

the emergency exit is available for use. The first observer’s seat can be released from stowed position and used as a step

when using the emergency exit in the door.

103




FIGURE 45

Control Cabin Door (Front Side)

104




FIGURE 46

Control Cabin Door Emergency Exit Panels Installation

105




52-70 DOOR WARNING

DOOR UNLOCK INDICATORS

The individual warning lights for the doors are located on the overhead panel, P5. The electronic equipment compartment

access door and the lower nose compartment door activate the same light, EQUIP, through individual microswitches. The

circuit is such that both doors must be latched in order to extinguish the warning light. The other warning lights are activated

by sensors operated by each individual door.

When a door is unlatched, the sensor or microswitch completes a circuit and illuminates the appropriate warning light on the

P5 panel. Closing and latching the door will extinguish the warning light. When all of the doors are closed and latched, the

DOORS annunciator light will extinguish.

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FIGURE 47

Door Unlock Indication

107




FIGURE 48

Door Warning System Schematic

108




ATA 56 WINDOWS

56-00 GENERAL

INTRODUCTION

The purpose of the airplane windows is to provide:

- Visual means to fly the airplane and for collision avoidance,

- emergency exit from the flight compartment,

- and an opening in the opaque fuselage through which the environment may be viewed.

The windows on the airplane are grouped as follows:

- Flight Compartment windows

- Passenger Compartment windows

- Inspection windows

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FIGURE 49

110




56-10 FLIGHT COMPARTMENT

FLIGHT COMPARTMENT WINDOWS

There are ten windows symmetrically located around the flight compartment. Windows No. 1, 3, 4 and 5 are fixed in

place. Window No. 2 is a sliding window, mounted on tracks, to permit ventilation and communication on the ground.

The construction of control cabin windows No. 1 and No. 2 consists of a glass pane laminated to each side of a polyvinyl

butyral (vinyl) interlayer or core. The inner glass pane is the thicker of the two and is the primary load carrying member.

The vinyl interlayer acts as the ―fail-safe‖ load carrying member and prevents the window from shattering if the inner

pane should break. The outer pane has no structural significance, but provides rigidity and a hard, scratch resistant

surface. A thin strip of parting medium is laminated around the window edges between the vinyl interlayer and each

glass pane. This is to prevent edge chipping of the glass under conditions of differential expansion and contraction.

A conductive coating of indium oxide applied on the inner face of the outer glass pane permits electrical heating for anti-

icing and defogging. The construction of No. 3 window consists of two stretched acrylic panes separated by a phenolic

spacer. The spacer is attached to the perimeter of the panes by pressure sensitive tape which also acts as an air seal.

The spacer provides an insulation cavity which prevents fogging on the inner surface of the windows. There is a small

hole in the upper forward corner of the inner pane. This hole must be open at all times to allow pressure in the air space

to equalize with pressure in the cabin.

Windows No. 4 and No. 5 are similar in construction in that both consist of a glass pane laminated to each side of a

polyvinyl butyral core. A conductive film, applied on the outer face of the inner glass permits electrical heating for

antiicing and defogging. No. 4 window, however, has an additional vinyl layer laminated to the inboard surface of the

inner pane. A cast acrylic sheet 15 laminated to the additional vinyl layer. These additional layers prevent glass from

scattering throughout the cabin in the event of bird impact. The additional layers are of no structural importance. A thin

parting medium is laminated around the window edges between the vinyl interlayers and each glass pane.

111




This is to prevent edge chipping of the glass under conditions of differential expansion and contraction. The window seals

which are used on the flight compartment windows consist of fixed window pressure seals, which are used on windows No.

1, 3, 4, and 5, and the sliding window pressure seals installed on windows No. 2. The primary purpose of the two types of

pressure seals is to prevent cabin pressurization leakage around the windows when the airplane is pressurized. The

sealants that are used on the windows prevent moisture penetration, water entrapment, and provide aerodynamic flushness

of the outer windowpane with the window frame.

112




FIGURE 50

Flight Compartment Windows Construction (Config.1)

113




WINDOW NO. 1

The No. 1 window is pressure sealed on installation by means of a gasket-like, molded-in-place rubber seal. The beaded

silicon rubber seal surface mates with the window frame to ensure an effective pressure and moisture-tight seal. The

pressure seal is an integral part of the window assembly and, in combination with a formed stainless steel Z-channel strip, is

bonded to the periphery of the windshield glass. Removal and installation should not be attempted without consulting the

current Maintenance Manual. Replacement windows are supplied with the necessary

parts for installation and with both sides of the pane covered with a protective

coating.

To remove a No. 1 window, not only must the window fasteners be removed but also any trim panels, crash padding,

windshield wipers, the light shield (P7 panel), sunshade support rod, drain tube clamps, and drain pan must also be

removed. Pressure is applied to the window from the outside, pushed into the cabin, and removed.

Some general precautions to observe include:

- Use only non-magnetic bolts along the top, bottom and forward edges of the window because of the proximity to the

standby compass.

-Use a staggered sequence, diagonally back and forth across the window, to tighten each nut to the correct torque value.

Damage to the window may result if the correct torque is exceeded. Consult the Maintenance Manual for the proper torque

values and a recommended staggered sequence.

IMPORTANT NOTE: PRIOR TO PERFORMING ANY MAINTENANCE OR CLOSE

INSPECTION ON THE CONTROL CABIN WINDOWS, BE CERTAIN THAT ELECTRICAL

POWER HAS BEEN REMOVED. BE CAREFUL WHEN WORKING ON THE WINDOW

SINCE THE OUTPUT VOLTAGE OF THE AUTO-TRANSFORMER RANGES FROM 250 TO

350 VOLTS.

114




FIGURE 51

WINDOW NO. 1

115




WINDOW NO. 3 (CONFIG 1)

Window No. 3 consists of two stretched acrylic panes separated by a phenolic spacer. The rubber cushion strip is bonded

to the metal backing plate. On installation, the strip is allowed to compress the window assembly so as to make a weather

seal from the pressure seal.

116




FIGURE 52

117




WINDOWS NO. 4 & 5

Windows No. 4 & 5 are similar in construction; No. 4 has the additional inner layers for bird strike protection. No. 5 has the

thermal switch bracket which must be aligned with the thermal switch location etched on the glass. When installing the

windows, consult the Maintenance Manual for the recommended staggered sequence for tightening the self-locking nuts.

118




FIGURE 53

Window No. 4 & 5 Installation

119




WINDOWS NO. 2

The No. 2 windows are mounted on tracks so that they may be rolled back to permit ventilation and communication during

ground handling operations. The laminated window pane, inner and outer glass separated by a vinyl core, has the

conductive film between the outer pane and the core where it is most effective for anti-icing. Mounted on the window frame,

at top and bottom, are glides which are guided along tracks attached to the airframe above and below the window. A

clothing guard covers the link mechanism along the lower edge of the window. The window can be removed by positioning

the lower glides with the track lip cutout.

To open the window, the trigger is squeezed and the handle rotated back and inboard. This rotates a bellcrank, which is

linked to other bellcranks at rear top and bottom of window, drawing the window inboard. The window may be moved to the

rear until the lower aft glide travels past the window open latch plate which is spring-loaded to lock the window in the open

position. To close the window, slide forward until the handle can be rotated forward and outboard. As the handle is rotated,

the window is moved outboard tightly against the window frame. The first officer’s window can be opened from the outside

on the passenger airplane. On a cargo airplane, both the captain’s and the first officer’s windows can be opened from the

outside.

IMPORTANT NOTE: PRIOR TO PERFORMING ANY MAINTENANCE OR

CLOSE INSPECTION ON THE CONTROL CABIN WINDOWS, BE CERTAIN

THAT ELECTRICAL POWER HAS BEEN REMOVED. BE CAREFUL WHEN

WORKING ON THE WINDOW SINCE THE OUTPUT VOLTAGE OF THE AUTO-

TRANSFORMER RANGES FROM 250 TO 350 VOLTS.

120




FIGURE 54

Right Window No. 2

121




56-20 PASSENGER COMPARTMENT

FUNCTIONAL DESCRIPTION

Passenger compartment windows are located between the fuselage frames in those areas where passenger seating is

provided.

The passenger compartment windows consist of outer, middle and inner panes. The inner pane is nonstructural and is

mounted in the sidewall lining. The outer and middle panes are each capable of taking the full cabin pressurization load.

Fail-safe structure is ensured by the middle pane which is designed for 1.5 times the normal operating pressure at 70

degrees Fahrenheit. The passenger compartment windows are plug-type windows. Installation and sealing of the

windows is through the use of a molded ethylene propylene seal. The outer pane of stretched acrylic plastic is

rectangular in shape with rounded corners and a beveled outer edge. The pane is curved to fair with the fuselage

contour. The middle pane of modified acrylic plastic sheet is similarly shaped but with an unbeveled edge. A small

breather hole is located near the bottom of the middle pane. Ten window retaining clips secure the window in the window

frame.

When installing the window, the entire window assembly is placed in the window frame. After the retaining clips are

installed loosely, the protective cover is grasped at least two inches from the edge and pulled towards the center. The

seal adheres to the outer surface of the outer pane. The clip adjusting screws are then tightened using a criss-cross

torque sequence. The seal protective cover is removed by cutting the cover on the notch center line following the

instructions in the Maintenance Manual carefully. The cover is then torn off at the notch line.

122




FIGURE 55

Passenger Cabin Window

123




SEAL LEAK DETECTION

Seal leakage is indicated if there is a pattern of smoke impingement on the outer window outboard of the breather hole in the

middle window. If leakage is indicated at the outer window it is advisable to change the middle panel and the seal/spacer. If

the seal leaks excessively, the middle window carries the pressurization load; this can cause structural deterioration.

124




FIGURE 56

Seal Leak Detection

125




EDGE DAMAGE

No surface chips are allowed in the middle pane. Small, shell shaped, edge chips no greater than 0.06 inch in the maximum

dimension are permissible. V-shaped edge chips shall be cause for removal of the middle pane. Creep deformation is middle

pane damage created by window clip against the edge of pane. Deformation is permissible within the following limits:

Without noticeable surface discontinuity, surface or edge is slightly displaced, but a fingernail cannot detect a discontinuity.

Noticeable discontinuity, but no evidence of a vee notch crack, window should be reworked. Surface discontinuity and a vee

notch crack less than 0.05 inch inward from edge of pane, window should also be reworked. If crack is greater than 0.05 inch

from edge replace the window. Crazing is defined as a series of small fissures perpendicular to the surface, but not

extending all the way through the pane. There are no surface breaks visible with crazing and it is difficult to see unless the

pane can be viewed from an angle so that light is reflected off the fissure surface. Crazing is usually the result of incorrect

window installation, producing higher than acceptable stress levels, or the application of unapproved fluids.

126




FIGURE 57

Edge Damage

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WINDOW CONCAVITY

Concavity of outer pane is the loss of forming contour causing the pane to move inward. In the event of extreme localized

distortion and thickness variances, check for uneven surface contour and reduced optical quality. Replace

window with concavity of this type. Gentle uniform concavity is not a reason in itself for window replacement. To check for

concavity place a straightedge across narrow width of pane. If a gap exists between the straightedge and the center pane,

the window is concave. Windows prone to fogging are prone to uniform concavity. Check the seals for leakage into window

cavity between outer and middle pane, and check window edges thoroughly for delamination. Replace the window if seals

are known to be leaking.

128




FIGURE 58

Window Concavity

129




56-40 INSPECTION AND OBSERVATION

INSPECTION WINDOW

The main gear down lock viewer provides a means for inflight visual inspection of the main gear down lock indicators. The

nose gear down lock viewer permits inflight visual inspection of the nose gear drag link locking components.

The main gear down lock viewer window is located in the floor near the aisle of the main cabin over the wheel well area. The

nose gear viewer window and cover are located in the flight compartment floor above the nose gear wheel well.

MAIN GEAR DOWN LOCK VIEWER

- A plywood cover is taped to the floor panel to protect the viewer window. The viewer consists of the window and two mirrors

mounted in an aluminum alloy viewer tube assembly which is attached to the wing center section pressure web structure.

NOSE GEAR DOWN LOCK VIEWER

- The viewer cover is attached to the floor and is opened to expose the viewer window. The viewer components are aligned

so the field of vision includes the nose gear lock space and the indicator.

130




FIGURE 59

Inspection Windows Location

131




FIGURE 60

Viewer and Observation Windows

132

Ata 51-57 Structure

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