Air Tractor, Inc. Repairs Page 5-i AT-802/802A July 30, 2008

Transcription

1 Repairs Page 5-i TABLE OF CONTENTS SECTION 5- REPAIRS No. Page FUSELAGE FRAME REPAIRS FORWARD CLAMP BLOCK BOLT FAILURE..5-1 STANDARD STRUCTURAL REPAIR DRAWINGS...5-1

2 Repairs Page 5-1 April 12, 2010 FUSELAGE FRAME REPAIRS The most common cause of fuselage frame damage is a landing gear strike during spraying operations, or hitting an obstruction during take-off. When a severe drag load is placed on the main gear leg and due to the leverage that exists, either the tubular structure is damaged or else the forward clamp block bolt fails. If the tubular structure is severely damaged it is best to contact the factory with photos or sketches of the damaged tubes, and a repair cluster can be constructed at the factory which can be spliced in a convenient location with external sleeves. It is seldom necessary to place the fuselage frame in the original jig, as shop aids can be sent with the repair structure, and with careful measurements, the structure will be back to the original configuration. Repair clusters are designed so that gas welding can usually be used to install the new cluster. The forward section of the fuselage frame, in the area where the main landing gear is attached, is heat treated for strength. Therefore, no field weld repairs are to be made to this area unless authorized by the factory. Many of the welded attach fittings are stress relieved. Weld repairs to these are acceptable, as long as the welds are stress relieved according to PS125. All other areas of the frame may be repaired by tig or gas welding in the field. Use FAA AC us a guide to general weld repairs. After welding, clean, sand, etch, prime and finish coat as described under PAINTING STEEL PARTS in Section 2- MAINTENANCE. FORWARD CLAMP BLOCK BOLT FAILURE If the wheel strike has caused the forward clamp block bolt to break, it is likely that the gear leg has folded back under the aircraft and broken the large inboard attach bolt and the aft clamp bolt. When the large inboard bolt fails, it usually damages the 1-1/2 OD bushing that it was attached to, and as the gear folds back the sharp edge of the gear leg damages the 3.0 diameter tube that the bushing is welded to. The broken bolts can be removed from the attach fitting by the conventional practice of drilling into the broken off bolt shank and using an Easy-Out tool to remove the bolt shank. Be careful not to damage the threads, but if there appears to be slight thread damage, use a 7/8-14 bottoming tap with a generous amount of cutting oil to re-work the threads, making sure that the tap is started exactly with the original threads. The damage to the 1 1/2 OD bushing is usually confined to the rear lower side, where the 1-1/8 bolt has bent before failing. Consult the factory for authorized repairs to this area. STANDARD STRUCTURAL REPAIR DRAWINGS The following sre standard structural reapir drawings. Reduced size drawings are shown on the following pages. To obtain full size drawings, please contact the factory. Drawing Repair of the Stabilizer Strut Fitting Drawing SK465 Weld Repair of the Main Gear Tube Drawing Repair of the Forward Lower Longeron Drawing Repair of the Aft Fuselage Frame Drawing Repair of the Wing Main Spar Splice Drawing Repair of cracks in the Wing Leading Edge Ribs Drawing Installation of Additional Wing Leading Edge Inspection Plates Drawing Repair of Oversize Holes in the Horizontal Stabilizer Attach Drawing Repair of Elevator or Rudder Hinges (2 Pages) Drawing Installation of the Tail Wheel Lock Bushing

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4 Page 5-3 Repairs April 12, 2010

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13 Page 5-12 Repairs