SD3-60 STRUCTURAL REPAIR MANUAL

Transcription

1 SRM STRUCTURES - GENERAL 1. Introduction This chapter contains structural repair information of a general nature pertaining to the complete aircraft. Areas particularly prone to damage are shown. Refer to Figure 1. Information is included on oning, and access for inspection and maintenance, and the materials used in original construction, together with a list of alternative materials, fastenings etc. which may be used in lieu of the original materials. Data on rivet and bolt types, and the methods of cut countersinking and dimpling is included and there is information on thermoplastic, fibreglass, Kevlar carbon fibre and honeycomb repair procedures. The illustrations in this chapter show details of general repairs applicable to the aircraft as a whole. 2. General The principal airframe assemblies are the fuselage, the outer and centre wings, flaps and ailerons the wing lift struts, the stub wings, and the tail unit consisting of single vertical and horiontal stabiliers. The assembly interconnecting points are the outer wings to centre wing, the centre wing to fuselage, the wing lift struts to the outer wing and stub wing, the vertical and horiontal stabiliers to the rear fuselage, the location of airfoil hinges and the attachments points of the retractable tricycle landing gear to the nose fuselage and the stub wings. Of the principal airframe assemblies, the structural members (rivetted and bolted assemblies) are built from sheet fabrications and are reinforced in the high strength locations of the airframe with extrusions and machined fittings. The main fuselage and the outer wings consist of thin inner, continuous corrugated skins of 0.75" circular arc corrugations at 3.0 pitch, bonded to outer skins and rivetted to the flanges of shear angles of the structural main members. The nose fuselage, rear fuselage, centre wing, fin, tailplane and stub wing are of conventional skin and stringer construction. The fuel tanks, manufactured in the form of light alloy box structures are housed within a fairing above the top fuselage skin running fore and aft of the centre wing section. These are subdivided into cells which are numbered 1, 2, 3 and 4 and are sealed to spec DTD 900/4506 (MIL-S-8802) with a rubber compound PR1422/A and PR1422/B, manufactured by the Product Research Corporation. For Frame Stations, Wing Stations, and other datums, refer to specific chapters. Page 1

2 3. Classification of Parts For the purpose of airworthiness requirements components and parts are classified in accordance with British Civil Airworthiness Requirements, Chapter D1-2, as follows:- CLASS 1 Those parts the failure of which, in flight or ground manoeuvres would be likely to cause catastrophic structural collapse, loss of control, power-unit failure, injury to occupants, unintentional operation of or inability to operate Essential Services or Equipment. NOTE: If the failure would lead to danger only through a second unlikely event (e.g. a broken aerial mast jamming the flying controls) the part is not considered to be in Class 1. CLASS 2 Those parts not in Class 1 of which more than visual examination is necessary to ensure reliability. CLASS 3 other parts. These classifications are referenced on the drawings of structure and skins in each Chapter. 4. Structurally Significant Areas It must be noted that certain components, and areas of the aircraft may be "CLASS 2", but are of major structural significance, i.e. components or areas which are highly stressed, or serve a structurally important function in the configuration of the aircraft. Any damage other than that classified as "owable", (Paragraph 3.A) must be reported to Short Brothers PLC without delay. Refer to Figure 2. A list of these structurally significant areas is as follows:- (1) Under fuselage tension strap. (at F.S. and R.S. Frames). (2) Fuselage F.S. and R.S. Frames. (3) Fuselage FRM 3 and FRM 74 (lower segment). (4) Keel walls. (5) Centre wing spar and spar box structure. (6) Outer wing spar and spar box structure. (7) Engine support structure. (8) Wing strut-attachment to stub wing (see note). (9) Wing strut-attachment to outer wing (see note). (10) Wing strut booms. Page 2

3 Parts of the Aircraft Prone to Damage Figure 1 Page 3

4 (11) Centre wing to fuselage draglink. (12) Stub wing primary structure (including shear deck) (13) Nose landing gear components. (14) Main landing gear components. (15) Vertical stabilier - attachment to fuselage. (16) Vertical stabilier - spars and sparbox structure. (17) Horiontal stabilier - spars, sparbox structure, rib attachments, and sparweb centre section. NOTE: Details of Outer wing (and Stub Wing) to Wing Strut joints. Refer to , pb1. Page 4

5 Structurally significant areas Figure 2 Page 5