AC NO: 20-59 DATE: 2/19/68
ANSPORT ADVISORY
ES OF I CIRCULAR MAINTENANCE INSPECTION NOTES FOR CONVAIR MODELS 240 AND 600/240D; MODELS 340/440 AND 640/340D/440D SERIES AIRCRAFT Consolidated reprint, February 1974;
includes change 1.
DEPARTMENT OF TRANSPORTATION
FEDERAL AVIATION ADMINISTRATION Initiated by: AFS-300
AC 20-59 CH 1 8/24/72 AC NU: 20-59 DATE: 2/19/68
ADVISORY
CIRCULAR
DEPARTMENT OF TRANSPORTATION
FEDERAL AVIATION ADMINISTRATION * SUBJECT: MAINTENANCE INSPECTION NOTES FOR CONVAIR MODELS 240 AND 600/240D; MODELS 340/440 AND 640/340D/440D SERIES AIRCRAFT *
1. PURPOSE. This handbook describes maintenance inspection notes which can be used for the maintenance support of certain structural parts * of Convair 240 and 600/240D; Models 340/440 and 640/340D/440D series aircraft.
2. DESCRIPTION. Maintenance on the wing, fuselage, and empennage structure is reviewed with a view toward supplementing information currently available.
HOW TO GET THIS PUBLICATION.
a. Order additional copies of this publication from:
Department of Transportation Federal Aviation Administration Distribution Unit, IAD-484.3 Washington, D.C. 20590
b. Identify this publication as: Advisory Circular 20-59 - * Maintenance Inspection Notes for Convair 240, 600/240D, 340/440, and 630/340D/440D Series Aircraft.
C. R. MELUGIN, JR.
Acting Director, Flight Standards Service Initiated by: AFS-300
AC 20-59 CH 1 8/24/72
TABLE OF CONTENTS
1. Introduction
2. Description 1
3. Background General Information S. Type of Construction
6. General Inspection Tips
7. Nondestructive Testing (NDT) APPENDIX 1 STATION CHARTS (Ba8ed z) Figure A-1 Wing Stations Figure A-2 Fuselage Stations 2 APPENDIX 2 FUSELAGE COMPONENTS (5 pages) Figure B-1 Fuselage Major Components Figure B-2 Fuselage Nose Section Figure B-3 Fuselage Cabin Section Figure B-4 Fuselage Tail Section Figure B-S Fuselage Stringer Diagrau 5 APPENDIX 3 WING COMPONENTS (5 pages) Figure C-1 Wing Components Figure C-2 Wing Leading Edge Structure 2 Figure C-3 Wing Inter-Spar Structure 3 Figure Co4 Wing Tailing Edge Structure Figure C-S Wing Tip Structure *APPENDIX 4 MAINTENANCE INFORMATION* (9 pages) 1 * APPENDIX 5 MODEL 240 AND 600/240D (5 pages) 1 (STC # SA 1054 WE) SERIES AIRCRAFT APPENDIX 6 MODEL 340/440 AND 640/340D/440D (STC # AS 1096 WE) SERIES AIRCRAF (6 pages) 1
AC 20-59 Page 1 2/19/68 INTRODUCTION. This advisory circular provides maintenance information which can be used by mechanics, repair agencies, owners, and operators in developing maintenance programs, making improvements in existing programs, and conducting inspections and repairs on certain structural parts of Convair 240, 340/440, 240T, and 340I airplanes. The material is based, in part, upon information made available through discussions with personnel who have maintained these types of airplanes for thousands of hours of time in service. The intent of the circular is to impart some of this knowledge to other interested persons so that it is not lost.
DESCRIPTION. The circular contains guidance material for performing maintenance on wing, fuselage, and empennage structure. The information has been derived from service experience. It does not comprise a full and complete maintenance program for the subject aircraft but should be considered as supplemental maintenance data. Included in the circular are diagramatic sketches and station identifications of the wing and fuselage.
in addition, there is a listing of selected maintenance difficulties which have been reported since 1964.
3. BACKGROUND.
Aircraft Use. The agency has realized that several different types of transport aircraft are being phased out of service by some airlines because of the availability of newer equipment. Such older aircraft are being purchased by other operators who may not be familiar with the scope of required maintenance and the means which have been used to keep the aircraft in a safe condition.
Maintenance "Know How." Since maintenance "know how" is not transferred with the aircraft, the new operator generally goes through a learning cycle before he is able to rapidly pinpoint the important/ critical problem areas of the aircraft. In this respect, identification of known areas where structural problems have been experienced will help in the preparation of an initial maintenance program by a new operator. It also can serve as a guide to other operators who have not accumulated sufficient service experience to have knowledge
4. GENERAL INFORMATION• * has pubion a several de Manufacturer's Bulletins. It must be emphasized that the manufacturer has published several service bulletins concerning the inspection, repair, and modification of Convair 240, 340/400, 240T, and 3401 aircraft. Service bulletins highlight the importance of maintaining known to have experienced crack and corrosion damage. Operators are make certain that responsible maintenance personnel are knowledgeable on this subject.
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Page 2 AC 20-59 2/19/68
b. Airworthiness Directive. It is emphasized that the material in this circular does not supersede any of the requirements of airworthiness directives issued under Part 39 of the Federal Aviation Regulations.
5. TYPE OF CONSTRUCTION. The major structural components of the aircraft are the wing group, the fuselage group, and tail group.
The full cantilever wing group consists of a center section integral with the fuselage and two removable outer panels. The outer panels include detachable tip sections and ailerons. The two-engine nacelles are bolted and riveted to the wing center section and include support beams on the outboard sides for installation of the main landing gear.
The all metal semi-monocoque fuselage consists of three sections:
nose section, cabin section, and tail cone section. Construction of the fuselage consists of longerons, longitudinal stringers, transverse bulkheads, formers, and support beams. The dorsal fin of beam and rib construction is riveted to the upper aft exterior surface of the fuselage along the center line.
c. The tail group is composed of the horizontal stabilizers with hinged elevators and vertical stabilizer with hinged rudder. The vertical and horizontal stabilizers are of full cantilever design and conventional spar and rib construction.
6. GENERAL INSPECTION TIPS.
Visual Inspection. The primary structure of the aircraft is designed to provide resistance to variable forces imposed while in operation by dispensing the forces through a structural pattern of 'force flow" to the primary structural members of the wing and fuselage. External indications of failure, such as distorted skin, tilted or sheared rivets, and torn, dented, cracked, or corroded skin are usually obvious. Wrinkled skin, "oil cans," and tilted rivets, adjacent to the obviously failed area often indicate secondary damage caused by transmission of stress from the failed area. Misalignment of doors and panels may indicate distortion of internal structure. Internal structural damage, although not always apparent, may be found by closely examining the exterior surface. For example:
Buckled skin between rivets at the end of a stiffener or stringer could mean that the last attaching rivet has failed, or that the stiffener or stringer is buckled in the area of the skin buckle. When a detailed inspection of the failed area is to be performed, functional parts should be actuated to determine if the failure has caused binding.
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AC 20-59 Page 3 2/19/68
(2) Deep diagonal skin buckles, located over a frame, former, or rib could mean the member is distorted. When doubt exists concerning internal condition, the area in question should be opened and carefully inspected.
7. NONDESTRUCTIVE TESTING (NDT).
Simply stated, nondestructive testing is preventive maintenance. This includes utilization of such maintenance tools as X-ray, ultrasonic, magnetic particles, eddy current, and dye penetrant.
Maintenance Inspection. NDT permits maintenance inspections without removing components from aircraft or tearing down complex assemblies.
Defects in various aircraft systems which would escape detection through normal visual inspection will be identified by NDT.
b. Training Required. Special NDT training is necessary to make sure that the operator is capable of operating the equipment and interpreting the results. Also, many states require that an X-ray operator have an approved certificate for use of X-ray in industrial applications. This is to minimize improper use with attendant health hazard of X-ray equipment.
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Page 4 AC 20- 59 2/19/68
AIRCRAFT STATION DIAGRAMS The wing, fuselage, and empennage station diagrams included in this document were developed for the CV-340 aircraft and are used as a general reference only. Several models of each of these aircraft were manufactured and have different station locator numbers based on the particular configuration. Since the defect areas generally apply to all models of both aircraft, the referenced area can be compared with a similar area and locator on the appropriate station diagram for the particular model of aircraft.
332 FIGURE A-1. WING STATIONS 523 545
WING STATIONS (IN INCHES) 189 332 Page 1 Appendix 1
WING STATIONS 545 (IN INCHES)
STATIONS FUSELAGE
LOOKING INBOARD 131 25 / 283 / 220 no go on LOOKING OUTBOARD 706 744 766 FIGURE A-2. FUSELAGE STATIONS 2/19/68 Page 2 AC 20-59 Appendix 1
CODE STRUCTURAL FIGURE 2/19/68 AC 20-59
COMPONENT REFERENCE
FUSELAGE NOSE SECTION FIG. B-2
2. FUSELAGE CABIN SECTION FIG. B-3
3. FUSELAGE TAIL SECTION FIG. B-4 FIGURE B-1. FUSELAGE MAJOR COMPONENTS
4. FUSELAGE STRINGER DIAGRAM FIG. B-5 Page 1 Appendix 2
5. NOSE BEAM CAP STRIP 4. NOSE SECTION BULKHEAD 109 3. PILOT'S COMPARTMENT ENCLOSURE NOSE CAP LONGERON 1. NOSE CAP COMPONENT CODE STRUCTURAL Page 2 Appendix 2 BOX BEAM NOSE GEAR SUPPORT FIGURE B-2. FUSELAGE NOSE SECTION
BEAM FLOOR SUPPORT
COMPARTMENT PILOT'S 2/19/68 AC 20-59
CODE STRUCTURAL 2/19/68 AC 20-59
COMPONENT
1. STOWAGE COMPARTMENT DOOR
2. TRANSVERSE SUPPORT BEAM
3. MAIN ENTRANCE DOOR
4. FUSELAGE PLATING AND STRINGER
5. CONSTANT SECTION BELTFRAME
6. FLOOR SUPPORT BEAM
7. HONEYCOMB FLOOR
8. OVER-WINGLONGERON
9. DOOR FRAME FIGURE B-3. FUSELAGE CABIN SECTION
CODE STRUCTURAL
COMPONENT
10. DOOR LONGERON OVER -WING FLOOR SUPPORT BEAM Page 3 Appendix 2