SD3-60 STRUCTURAL REPAIR MANUAL

Transcription

1 SD3-60 STRUCTURAL REPAIR MANUAL z SRM AERODYNAMIC SMOOTHNESS 1. Introduction This section covers the requirements for the maintaining of aerodynamic smoothness, when repairs to the aircraft surface have been carried out. Deviations from the following requirements are not permitted without first obtaining agreement from Bombardier Aerospace (Belfast) - see INTRODUCTION to this manual, for details of APPLICATION FOR REPAIR/DAMAGE REPORT procedures. 2. General For the purposes of tolerance requirements the aircraft is divided into three classification zones each with its own limits of deviation from basic aerodynamic smoothness. These are explained on the following pages, which also cover mis-match, flushness, bulges, waviness, contour deviations, and surface texture. The requirements for the, "as manufactured", aerodynamic smoothness of the aircraft are covered in detail by Bombardier Aerospace (Belfast) document TDAS/SD3-601, a copy of which may be obtained on request. 3. Surface Classification The classification arrangement adopted for the exterior surface of the major components of the SD3-60 aircraft is outlined below. Standards associated with this classification for skin surface waviness, contour deviation and surface imperfections etc are defined. Page 1

2 z SD3-60 STRUCTURAL REPAIR MANUAL Classification Arrangement Figure 1 Page 2

3 SD3-60 STRUCTURAL REPAIR MANUAL z 4. Waviness & Contour Deviation - Definitions A. Waviness Refer to Figure 3. The Mean Local Contour is that obtained using a flexible spline, as illustrated. Limitations on the permissible waviness height has defined in the sketch above are given in terms of the wavelength L. Refer to Figure 4. B. Contour Deviation (see note below) Refer to Figure 3. A contour deviation is defined as the difference between the Production Loft Contour and the Mean Local Contour, ignoring Local Waviness and other surface imperfections, as illustrated in the above sketch. To check contour deviation, templates located by fixed tooling points are required. NOTE: the definition of Contour Deviation is included for ref only to illustrate the distinction between waviness a contour errors. As special, production tooling is required to verify this characteristic no requirement is imposed by the SRM to check same - if in doubt consult Bombardier Aerospace, Belfast. 5. Skin Surface Waviness - Limits Refer to Figure 4. The allowable surface contour waviness, both parallel and normal to the airstream, has been defined in three classes. Page 3

4 z SD3-60 STRUCTURAL REPAIR MANUAL Waviness Figure 2 Page 4

5 SD3-60 STRUCTURAL REPAIR MANUAL z Contour Deviation Figure 3 Page 5

6 z SD3-60 STRUCTURAL REPAIR MANUAL Wave Length L - inches Figure 4 Page 6

7 SD3-60 STRUCTURAL REPAIR MANUAL z 6. Tolerances on Surface Imperfections due to Fasteners and Spot Welding A. Permitted fixings The permitted types of rivets, screws and bolts on the outer surface of the aircraft are given under the repairs section of each chapter. For full details of:- - Materials. Refer to , pb1. - Hardware. Refer to , pb1. B. Rivets and Spot Welding The permitted tolerance for nominal flush rivets and spot welding relative to the surrounding sheet is:- (1) Refer to Figure 5. For all rivets and spot welding between LE and 5% chord of all aerofoil surfaces and controls the tolerance is: h = in. (0.05 mm) in. (0.08 mm) (2) Refer to Figure 5. For all other flush rivets and spot welding the tolerance is: h = in. (0.10 mm) for 95% coverage h = in. (0.15 mm) for 5% coverage (3) where mushroom head, Avdel or domehead pop rivets are permitted the minimum size is to be used subject to agreement with Aerodynamics. C. Screws and bolts (1) Refer to Figure 5. The permitted tolerance for nominal flush screws and bolts relative to the surrounding sheet is: h = in. (0.10 mm) in. (0.15 mm) Refer to Figure 5. On wings and tail unit in way of de-icing boots: h = +0 (+0) in. (-0.10 mm) (2) Mushroom head bolts and screws may only be used after agreement with Aerodynamics. Page 7

8 z SD3-60 STRUCTURAL REPAIR MANUAL Surface Imperfections due to Rivets & Bolts etc Figure 5 Page 8

9 SD3-60 STRUCTURAL REPAIR MANUAL z 7. Tolerances on Gaps and Mismatches A. General General rules for maximum tolerances on gaps and mismatches on all aircraft surfaces are given below. These rules are applicable to all surfaces except the Nacelles, Doors & Windows which are dealt with separately - see following pages. (1) Gaps. Refer to Figure 6. (a) Skin panels Class A B C Tolerance G in (0-1.1 mm) in (0-1.6 mm) in (0-1.9 mm) (b) Access panels Class B C Tolerance G in (0-1.9 mm) in (0-2.2 mm) (2) Mismatches. Refer to Figure 7. (a) General Class (b) Wings, Tailplane and Fin Maximum Tolerance M Into Wind Out of Wind Parallel to Wind A 0.012in (0.30mm) 0.016in (0.40mm) 0.028in (0.7mm) B 0.016in (0.40mm) 0.024in (0.6 mm) 0.028in (0.7mm) C 0.020in (0.50mm) 0.024in (0.6mm) 0.028in (0.7mm) For wings, tailplane, and fins, the maximum allowable Into Wind mismatch for all structure classes (A, B and C) is in (0.30 mm). Page 9

10 z SD3-60 STRUCTURAL REPAIR MANUAL Gaps Figure 6 Page 10

11 SD3-60 STRUCTURAL REPAIR MANUAL z Mismatches Figure 7 Page 11

12 z SD3-60 STRUCTURAL REPAIR MANUAL (3) Doublers Refer to Figure 7. Skin doublers and butt straps should be fitted on the internal surfaces wherever possible. Where external doublers are unavoidable and are more than in (0.55mm) in thickness all edges should be chamfered as shown in accordance with the following:- (Except that on the doubler at Frame 74.0 θ may be 25 in the area of the flight deck side windows.) Doublers where used and which are 0.022in (0.55 mm) in thickness or less should have radius treatment on all outer edges (ie normal deburring is required). 8. Fuselage Gaps and Mismatches (Doors, hatches etc) A. Doors a = in (0.30 mm) normal to wind = in (0.55 mm) parallel to wind o = 15 door edges with the exception of the nose landing gear bay doors must be sealed. (Chapter 52 refers). The gap dimensions in 8.A.(1) and 8.A.(2) below satisfy aerodynamic requirements. It should be noted that in order to prevent water and air leaks through seals the requirements quoted in ICY drawings must also be complied with. (1) Passenger door, freight door, side emergency exits and aft baggage door. Gap: 0.012in (3.0 mm) maximum Except up to 0.20" (5.0 mm) over 10% of door periphery. (Not more than 15 inches length in one place) Mismatch: Into wind; 0.04 in (1.0 mm) maximum Out of wind; 0.08 in (2.00mm) maximum on all sides, provided door and coaming edges have 0.10 in (2.5 mm) radius applied. Page 12

13 SD3-60 STRUCTURAL REPAIR MANUAL z (2) Forward baggage door and ditching hatch Gap: Mismatch: Cross-wind; 0.10 in (2.5 mm) maximum Streamwise; 0.12 in (3.0 mm) maximum, except 0.15 in (3.8 mm) over 20% length (Not more than 12 inches length in one place) Into wind; 0.025in (0.65 mm) maximum Out-of-wind; 0.050in (1.3mm) maximum treamwise; in (1.8 mm) maximum door and coaming edges to have 0.10 in (2.5 mm) radius applied. (3) Nose landing gear bay doors Gap: Mismatch: 0.12 in (3.0 mm) maximum ± 0.04 in (1.0 mm) maximum on all sides, provided door and coaming edges have 0.10 in (2.5 mm) radius applied on edges. B. Flight deck windows Step not to exceed 0.10 in (2.5 mm). 25 chamfer to be applied on securing straps. Refer to , pb1. 9. Nacelles - Gaps and Mismatches A. General General requirements on surface waviness are given in paras 4 and 5, and requirements on mismatches in para 7. B. Cowlings, Doors and Access panels Requirements for the joints between the nacelle and cowlings, doors and access panels are:- Gap: in (1.9 mm maximum) unless otherwise stated Mismatch: in (1 mm) into or out-of-wind on final assembly. For longitudinal edges or joints a mis-match not greater than 0.060" (1.5 mm) over up to 25% of the length of each continuous joint will be accepted, with a maximum mismatch of 0.040" (1mm) applying over the remainder of each joint. Edges of all cowlings, doors and access panels to be de-burred. such edges must be sealed. Page 13

14 z SD3-60 STRUCTURAL REPAIR MANUAL The gap between the lower engine cowl and the nacelle monocoque structure to be not greater than: 0.150" (4 mm) below the lower cowl hinge-line 0.080" (2 mm) above the lower cowl hinge-line The edges of the joint below the lower cowl hinge-line to be de-burred and rounded as much as feasible. Gaps on the nacelle aft of the wing Forward Spar Datum to be not greater than 0.10 in (2.5 mm). The streamwise gap between the nacelle and the wing upper surface at the leading edge to be not greater than 0.15 in (3.8 mm). 10. Surface Roughness due to Paint Care should be taken to achieve a good paint finish avoiding excessive graininess, ripple, lemonpeel effect, and discrete irregularities. In particular the ridges left at the edges of painted surfaces where masking tape has been peeled off must be removed. 11. Surface Finish of Composite Sheets The surface finish of composite sheets should be at least as good as painted surfaces, as specified in para 10. above. Page 14