Appendix 7 AC 20-52 CHG 1 Page 2 7 Jul 72
c. Crew and Cargo Door Area.
(1) Location. Forward fuselage, right hand side (See Figure G-5, Appendix 7).
(2) Applies to DC-6/7 series aircraft.
(a) Action. Periodic inspections of crew door jamb, adjacent skin, longerons, and nose to fuselage attach angles until Service Bulletin 865 has been accomplished.
(3) Other Reference Documents.
(a) DC-6/-7 Advisory Circular 20-52 Appendix 4, Pages 3 and 4.
(b) DC-6 Service Bulletins 616, A636, 636, 731, 775, 788, 815, and 865.
(c) DC-7 Service Bulletins 182, A218, 218, 275, 316, and 417.
(4) Probable Consequences. Extensive fuselage cracks in this area may lead to more serious structural damage.
(5) Recommendations.
(a) Periodic inspections should be continued until Service Bulletin 865 or 417 is incorporated.
(b) Periodic inspections should be continued after incorporation of the Service Bulletin 865 or 417 to assure continued structural integrity.
d. Vertical Stabilizer Front Spar-to-Fuselage Attach Fittings.
(1) Location. (See Figure G-6, Appendix 7).
(a) Fuselage Station 1033 (DC-6).
(b) Fuselage Station 1073 (DC-7).
(2) Applies to DC-6 series aircraft.
Action. Applies to all model DC-6 series aircraft prior to fuselage number 221 except 214.
1 If cracked beyond limits specified, the part should be replaced with improved fitting prior to next flight.
If original part is not replaced, inspection should be performed every 3500 hours.
DC-7 - None.
AC 20-52 CHG 1 Appendix 7 7 Jul 72 Page 3
(3) Other Reference Documents.
(a) DC-6/-7 Advisory Circular 20-52, Appendix 4, Page 15.
(b) DC-6 Service Bulletins 796 and A796.
(c) DC-7 Service Bulletin 407.
(4) Probable Consequences. Failure of fitting could result in a serious loss of structural integrity of the vertical stabilizer.
(5) Recommendations. Periodic inspection of original or improved fittings to assure continued structural integrity.
e. Main Entrance Door Area.
Location. Aft fuselage, left hand side (see Figure G-7, Appendix 7).
(2) Applies to DC-6/l series aircraft.
(3) Other Reference Documents.
(a) DC-6/-7 Advisory Circular 20-52, Appendix 4, page 12.
(b) DC-6 Service Bulletin 583.
(c) DC-7 Service Bulletins 317 and 400.
(4) Probable Consequences. Extensive cracking in this area could result in more serious structural damage.
(5) Recommendations. Periodic inspections to assure continued structural integrity.
Fuselage Frames at Wing Upper Spar Cap Attach Area.
(1) Location. Wing-to-fuselage attach area (see Figure G-8, Appendix 7).
(2) Applies to DC-6/7 series aircraft.
(3) Other Reference Documents.
(a) DC-6/-7 Advisory Circular 20-52, Appendix 4, page 8.
(b) DC-6 Service Bulletins 611, 640, 652, and 789.
(c) DC-7 Service Bulletins 59 and 346.
Appendix 7 AC 20-52 CHG 1 Page 4 7 Jul 72
(4) Probable Consequences. Continued cracking can result in a significant loss in strength of the wing to fuselage attachment.
(5) Recommendations. Periodic inspections to assure continued structural integrity.
g. Horizontal Stabilizer-to-Tail Stub Front Spar Attach Fittings.
(1) Location. Outboard end of horizontal stabilizer center section (see Figure G-9, Appendix 7).
(2) Applies to DC-6 series aircraft.
(a) Action. Applies to following DC-6 aircraft: serial numbers 42854 to 42894 inclusive, 43000 to 43012 inclusive:
43055, 43056, and 43062.
A 0.25 inch diameter stop hole should be drilled through the spar cap tang as crack stopper.
Periodic inspection is important when the stop drill hole is incorporated.
DC-7 (None).
(3) Other Reference Documents.
(a) DC-6/-7 Advisory Circular 20-52, Appendix 6, Page 5.
(b) DC-6/-7 Advisory Circular 20-52, Appendix 4, Page 14.
(c) DC-6 Service Bulletin 831.
(d) DC-7 Service Bulletin 410.
(4) Probable Consequences. Continued cracking could significantly reduce the strength of the horizontal stabilizer spar joints.
(S) Recommendations. Periodic inspections to assure continued structural integrity.
h. Wing Lower Front and Lower Center Spar Caps at Wing Station 30.
(1) Location. Intersection of lower front and center spar caps and wing-to-fuselage attach angle (see Figure G-10 Appendix 7).
AC 20-52 CHG 1 Appendix 7 7 Jul 72 Page 5
(2) Applies to DC-6 series aircraft.
(a) Action.
44064, 44069-44073, 44076, 44257. DC-6B serial numbers 43257-43259, 43201-43270, 43291, 43292, 43298-43300, 43518- 43537, 43539-43547, 43549-43555, 43557-43564, 43738-43741, 43743-43740, 43748-43750, 43820-43822, 43824-43826, 43828- 43834, 43836, 43837, 43842, 43844-43847, 44056-44062, 44080-44083, 44087-44089, 44102-44113, 44165-44168 and 44251.
1 If cracks are found, temporary or permanent repair should be made.
After permanent repair is incorporated, normal repetitive inspection should be made at intervals not to exceed 3,200 hours time in service.
3 DC-7 - None.
(3) Other Reference Documents.
(a) DC-6/-7 Advisory Circular 20-52, Appendix 5, Page 1.
(b) DC-6 Service Bulletins A720, 720 and A821.
(4) Probable Consequences. Cracking of spar cap tangs could lead to more serious structural damage.
(5) Recommendations. Periodic inspections of this area to assure continued structural integrity.
1. Wing Front, Center, and Rear Spar Caps at Station 60.
(1) Location. Upper and lower, front, center and rear spar cap tangs at station 60 bend area (see Figure G-11, Appendix 7).
(2) Applies to DC-6/7 series aircraft.
(a) Action. Applies to all DC-6, DC-6A and DC-6B aircraft fuselage number 1 up to and including fuselage number 722 having an excess of 9000 hours in service and to all DC-7 and DC-7B aircraft fuselage number 1 up to and including fuselage number 720 having in excess of 8000 hours time in service.
Temporary or permanent repair should be made if cracks are found.
2 Periodic inspections should be performed if permanent repair is not incorporated.
Appendix 7 AC 20-52 CHG 1 Page 6 7 Jul 72
(3) Other Reference Documents.
(a) DC-6/-7 Advisory Circular 20-52, Appendix 5, Pages 3 and 4.
(b) DC-6 Service Bulletins A678, 678, 694, 763, 824, and 857.
(c) DC-7 Service Bulletins 167 and 406.
(4) Probable Consequences. Chordwise cracks in spar caps could result in failures in adjacent wing skins and stringers, causing a serious loss of structural integrity.
(5) Recommendations. Periodic inspections after incorporation of respective reworks.
j. Lower Front Spar Cap Splice at Main Landing Gear Drag Attach Brace Fitting.
(1) Location. Wing stations 131 and 167 front spar lower cap aft tang and splice plates (see Figure G-12, Appendix 7).
(2) Applies to DC-6 series aircraft.
Action. Applies to all models DC-6, DC-6A and DC-6B aircraft serial number 42854 up to and including serial number 44429.
1 A rework should be performed if cracks exist.
2 Inspection should be made for preloaded flanges.
3 DC-7 - None.
(3) Other Reference Documents.
(a) DC-6/-7 Advisory Circular 20-52, Appendix 5, Page 8.
(b) DC-6 Service Bulletins 532, 749, 802, and 862.
(c) DC-7 Service Bulletins 345 and 414.
(4) Probable Consequences. Cracking in this area could reduce load carrying capability front spar splices.
(5) Recommendations. Periodic inspections to assure continued structural integrity.
k. Lower Center Spar Cap Splice at Wing Station O.
(1) Location. Wing Station O (see Figure G-13, Appendix 7).
(2) Applies to DC-6/7 series aircraft.
AC 20-52 CHG 1 Appendix 7 7 Jul 72 Page 7 (and 8)
(3) Other Reference Documents.
(a) DC-6/-7 Advisory Circular 20-52, Appendix 5, Page 1.
(b) DC-6 Service Bulletin 854.
(4) Probable Consequences. Continued cracking of center spar lower cap could result in more extensive structural damage to the wing lower panel.
(5) Recommendations. Periodic inspections to assure continued structural integrity.
(6) VERTICAL STABILIZER FRONT SPAR-TO-FUSELAGE 7 Jul 72 AC 20-52 ATTACH FITTINGS (Page 14) CHG 1
(3) EMERGENCY EXIT DOOR HINGES (Page 11) _(4) EMERGENCY EXIT DOOR HINGE CUTOUT (Page 12)
(5) CREW and CARGO DOOR FIGURE G-1. DC-6/7 FUSELAGE/EMPENNAGE AREA (Page 13)
•000 < (7) MAIN ENTRANCE DOOR AREA (Page 15)
(8) FUSELAGE FRAMES AT WING UPPER SPAR CAP ATTACH AREA (Page 16)
(9) HORIZONTAL STABILIZER-TO-TAIL
STUB FRONT SPAR ATTACH FITTINGS (Page 17) Page 9 Appendix 7 DC-6/-7 FUSELAGE/EMPENNAGE STRUCTURAL INSPECTION ITEMS
(13) LOWER CENTER SPAR CAP Page 10 Appendix 7 SPLICE AT WING STA. 0 (Page 21)
(11) WING FRONT CENTER AND REAR SPAR CAPS AT STATION 60 (Page 19) FIGURE G-2.
DC-6/7 CENTER WING
(10) WING LOWER FRONT AND (12) LOWER FRONT 7 Jul 72 AC 20-52 CHG 1 LOWER CENTER SPAR CAPS SPAR SPLICE AT M.L.G.
AT WING STA. 30 (Page 18) DRAG BRACE ATTACH FITTING (Page 20) DC-6/-7 CENTER WING STRUCTURAL INSPECTION LOCATIONS
AC 20-52 CHG 1 Appendix 7 7 Jul 72 Page 11 FIGURE G-3. EMERGENCY EXIT DOOR HINGES VIEW A
EMERGENCY EXIT DOOR
HINGE FITTING INSPECT DOOR SKIN RECESS 1" RADIUS
Appendix 7 AC 20-52 CHG 1 Page 12 7 Jul 72 FIGURE G-4. EMERGENCY EXIT HINGE CUTOUTS
INSPECT HINGE CUTOUT
FOR POSSIBLE CRACKING
VIEW A EMERGENCY EXIT DOOR
AC 20-52 CHG 1 Appendix 7 7 Jul 72 Page 13 FIGURE G-5. CREW AND CARGO DOOR AREA LONG. 11 LONG. 17 LONG. 13 TYP. CRACK LOCATIONS LONG. 14 FUS. SKIN