WING STATIONS - DC-6/7 AIRCRAFT INSPECTIONS Page 8 Appendix
WING DESCRIPTION INSPECT COMMENTS INSPECTION REMARKS
STATION FOR TOOLS W.S. Splice or tie plates, Cracks Access thru Visual, (1) Cracks located 131 landing gear, spar wheel well Dye Penetrant horizontally in lower cap, lower front X-ray cap where plates attach.
(2) Routine inspection necessary.
W.S. Center wing lower Cracks and Outside sur- Visual or (1) Moderate to heavy 131 skin aft of center Corrosion face inspec- X-ray corrosion.
spar tion
(2) Frequent and close inspection of this area recommended.
W.S. Aft and of main land- Cracks and Outside Visual or (1) Moderate to light 131 ing gear door Corrosion surface X-ray corrosion.
assemblies inspection
(2) Cracks radiating from aft row of rivets.
W.S. Lower wing skin Sma11 (Ref: DSBs Visual or (l) Corrosion can become 167 - cracks and 406 & 857) X-ray severe.
282 corrosion
(2) Frequently inspect this area.
NOTE: Refer to manufacturer's manual for skin repair and corrosion treatment.
8/24/67 AC 20-52
WING STATIONS - DC-6/7 AIRCRAFT INSPECTIONS 8/24/67 AC 20-52
WING DESCRIPTION INSPECT COMMENTS INSPECTION REMARKS
STATION FOR TOOLS W.S. Leading edge rib Cracks (Ref: DSBs Visual or (1) Routine inspection of 183 406 & 857) X-ray this area.
W.S. Stringers caps and Cracks None x-ray (1) Cracks located in 203 - crowns inside and fastener holes.
282 out, loose rivet (2) Crack length up to 2" long.
W.S. Wing skin and large Cracks Outside Visual (1) Cracks located parallel 281 fasteners surface to ribs.
inspection
(2) Crack length up to 4" long• W.S. Stringer tie ends Corrosion Access door Visual (1) Moderate to heavy 281 corrosion.
(2) Frequent inspections of this area.
W.S. Stringer No. 23 Cracks and Internal Visual or (1) Particular attention 242 inboard/outboard of loose inspection X-ray should be given this W.S. rivets access door area.
NOTE: Refer to manufacturer's manual and service bulletins for crack repair and corrosion Page 9 Appendix treatment.
WING STATIONS - DC-6/7 AIRCRAFT INSPECTIONS Page 10 Appendix 5
WING DESCRIPTION INSPECT COMMENTS INSPECTION REMARKS
STATION FOR TOOLS
w.S. Leading edge access Corrosion Internal Visual or (1) Corrosion is moderate to 242 door plate hinge, aft and wear inspection x-ray severe.
tang access door
(2) Frequent cleaning treatment necessary.
W.S. Frame of nacelle Cracks Access thru Visual (1) Nuisance cracks.
130 - where attached to inspection 167 skin opening on (2) Routine inspection 300 - nacelles necessary.
336 W.S. Wing skin behind out- Corrosion Outside Visual (1) Corrosion is severe.
318 board nacelle (sma11 surface pits) inspection (2) Frequent cleaning is necessary.
W.S. Wing skin under Cracks Nacelle must X-ray (1) Cracks vary in length 149 - nacelle turtle back be removed up to 2".
318 to locate cracks (2) Particular attention should be given this area.
W.S. Supercharger mount Cracks Access thru Visual (1) Transverse cracks have 318 frames inspection been reported.
door
(2) This area should be given frequent inspections. 8/24/67 AC 20-52 NOTE: Refer to manufacturer's manual and service bulletins for crack repair and corrosion treatment.
WING STATIONS - DC-6/7 AIRCRAFT INSPECTIONS 8/24/67 AC 20-52
WING DESCRIPTION INSPECT COMMENTS INSPECTION REMARKS
STATION FOR TOOLS W.S. Fuel tank sealants Corrosion Access door Visual (1) Corrosion found on wing 281 skin when sealants removed.
(2) Frequent inspections of this area.
W.S. Wing skin Cracks and Outside Visual or (1) Particular attention should 281 fuel leaks surface X-ray be given this area. Consult inspection manufacturer if repair not in repair manual.
W.S. Upper spar rail Corrosion Access thru Visual or (1) Corrosion light to moderate.
281 landing gear X-ray well (2) Area should receive frequent attention.
W.S.
281 "Tee" angles Cracks Internal Visual or (1) None inspection x-ray access door
w.S. Stringer No. 22 aft of Cracks and Internal Visual or (1) Cracks are usually in for- 293 center spar inboard/ loose inspection X-ray ward line of rivets.
outboard of W.S. rivets access door
(2) Routine inspections necessary. Page 11 Appendix 5 NOTE: Refer to Douglas Service Bulletins Nos. 406 and B57 for additional information.
WING STATIONS - DC-6/7 AIRCRAFT INSPECTIONS Page 12 Appendix 5
WING STATION DESCRIPTION INSPECT FOR COMMENTS INSPECTION TOOLS REMARKS W.S. Stringer No. 23 aft Cracks and Internal Visual or (1) Crack location - on both 293 of center spar 1oose inspection x-ray forward and aft row of inboard/outboard of rivets access door rivets.
W.S.
(2) Check for loose rivets.
W.S. Stringer No. 22 Cracks and Internal Visual or (1) Crack location - aft row 242 inboard/outboard of 'loose inspection x-ray of rivets.
W.S. rivets access door
(2) Length of cracks reported up to 2".
W.S. Nacelle former flangesCracks Access thru Visual (1) Crack location - parallel 300 '(nacelle station 414) inspection to former. Area should 336 plate receive close attention.
W.S. Nacelle to center Cracks Access thru Visual (1) Cracks start in gussets 149 - spar attach gussets inspection and parallel to spar cap.
318 (nacelle station 460) plate
(2) Routine inspections necessary.
W.S. Front spar cap for- Cracks Access thru Visual or (1) Cracks in tang found up 149 ward lower tang at landing gear X-ray to 4" long.
No. 3 inboard and wheel well outboard nacelle attach angle boltholes NOTE: Refer to manufacturers manual and service bulletins for repair instructions. 8/24/67 AC 20-52
WING STATIONS - DC-6/7 AIRCRAFT INSPECTIONS 8/24/67 AC 20-52
WING DESCRIPTION INSPECT COMMENTS INSPECTION REMARKS
STATION FOR TOOLS
w.S. Front spar cap for- Cracks Access thru Visual or (1) Cracks in tang radiate 318 ward lower tang at landing gear X-ray from rivet line.
No. 4 inboard and wheel well outboard nacelle attach angle bolts W.S. Center lower spar Cracks Access thru Visual or (1) Cracks are located in 302 cap forward tang at landing gear X-ray fastener holes and also 312 fuel sump cutout wheel well in wing skin.
radius in cap inboard (W.S. 302) and out- (2) Crack length ranges up board (W.S. 312) end to 2" long.
of numbers 1 and 4 alternate tank sumps (bolts removed) W.S. Fasteners inboard of Cracks Outside sur- Visual (1) Cracks radiate from 336 outboard nacelles face inspec- fastener holes parallel tion to ribs.
W.S. Center spar upper Cracks Access thru Visual (1) Cracks are located in 339 rail main landing X-ray the skin attach points.
gear wheel well (2) Routine inspection is necessary.
NOTE: Refer to manufacturer's repair manual and service bulletins for repair instructions. Page 13 Appendix
WING STATIONS - DC-6/7 AIRCRAFT INSPECTIONS Page 14 Appendix 5
WING DESCRIPTION INSPECT COMMENTS INSPECTION REMARKS
STATION FOR TOOLS W.S. Stringer No. 26 hat Cracks/ Access thru Visual (1) Corrosion moderate to 421 sections and attach Corrosion inspection X-ray heavy.
fittings door
(2) Cleaning and painting will control.
W.S. Wing stringer No. 22 Cracks/ Access thru Visual (1) Corrosion moderate to 336 (outboard of this Corrosion inspection X-ray heavy.
station) door
(2) Area should be frequently inspected.
W.S. Wing stringer No. 23 Cracks/ Access thru Vișual (1) Corrosion moderate.
336 (outboard of this Corrosion inspection X-ray station) door (2) Cracks parallel stringer longitudinally.
W.S. Wing stringer No. 22 Cracks / Access thru Visual (1) Corrosion moderate.
378 (inboard and outboard Corrosion inspection X-ray of this station) door (2) Cracks range up to 3" long• W.S. Wing stringer No. 23 Cracks/ Access thru Visual (1) Corrosion light to 378 (inboard and outboard Corrosion inspection X-ray moderate.
of this station) door
(2) Frequent inspections necessary.
NOTE: Refer to manufacturer's repair manual and service bulletins for repair information. 8/24/67 AC 20-52
WING STATIONS - DC-6/7 AIRCRAFT INSPECTIONS 8/24/67 AC 20-52
WING DESCRIPTION INSPECT COMMENTS INSPECTION REMARKS
STATION FOR TOOLS W.S. Wing stringer No. 22 Cracks/ Access thru Visual (1) Severe corrosion reported.
399 (inboard and outboard Corrosion inspection X-ray of this station) door (2) Cracks are longitudinal, crack length up to 3" long• W.S. Wing stringer No. 23 Cracks/ Access thru X-ray (1) Corrosion moderate to 399 (inboard and outboard Corrosion inspection heavy.
of this station) door
(2) Cracks involve stress corrosion.
W.S. Inboard end of wing Corrosion Internal Visual (1) Corrosion light to 421 and lower and of inspection moderate.
attach fittings and access door stringers (2) Sealant area must be inspected.
W.S. "Tee" clips at end Cracks None Visual (1) None 421 of spars X-ray W.S. Upper wing skin at Cracks Outside Visual (1) Cracks parallel rivet 435 - skin lap at front surface row.
453 spar inspection
(2) Routine inspection is necessary. Page 15 Appendix 5 NOTE: Refer to manufacturer's repair manual and service bulletins for repair information.
WING STATIONS - DC-6/7 AIRCRAFT INSPECTIONS Page 16 Appendix
WING DESCRIPTION INSPECT COMMENTS INSPECTION REMARKS
STATION FOR TOOLS W.S. Rib clips (90°) Cracks Internal Visual (1) Cracks radiate from 421 inspection fastener holes on 710 access door stringer and/or rib./ W.S. Aileron well Sma 11 Outside Visual (1) Routine inspection of 421 - cracks surface this area.
705 inspection W.S. Aileron trim tab Sma11 Outside Visual (1) Particular attention 462 hinge points cracks surface should be given this 517 inspection area.
W.S. Aileron bell crank Cracks Internal Visual (1) *Failure have been 485 inspection reported due to wing access door gust loads on ground.
(See Note 1) W.S. Wing trailing edge Nuisance Internal Visual (1) These areas should 60 - skin, ribs, clips, cracks inspection receive frequent 710 and stringers and also on inspections.
outside surface (Ref:
DSBs 406 &
857) NOTE: Refer to manufacturer's manuals and service bulletins tor repair and corrosion treatment information.
NOTE 1. * Fiber glass trailing edge will develop small cracks in radius at tip. (Maintenance item) 8/24/67 AC 20-52
WING STATIONS - DC-6/7 AIRCRAFT INSPECTIONS 8/24/67 AC 20-52
WING DESCRIPTION INSPECT COMMENTS INSPECTION REMARKS
STATION FOR TOOLS W.S. Wing trailing edge Corrosion Outside Visual (1) Corrosion moderate to 60 and flap well area surface heavy due to exhaust gases.
470 inspection
(2) Frequent and close inspection of these areas recommended.
(3) Frequent cleaning and treatment necessary.
W.S. Wing flap links Cracks and Outside Visual (1)*Routine inspection of this 167 Misalign- surface area desirable. (See 281 ment inspection Note 1) 334 W.S. Wing flap support aft Oversize Service wear Visual (1) Routine inspection of 167 boltholes hole this area.
W.S.
281 Spacer block/flap Improper None Visual (1) None actuator clearance NOTE 1. * Misalignment of links will result in cracking the link and attach brackets. Also, it will Appendix 5 impose large loads on brackets that are attached to the rear spar structure which can result in cracking in this area.
WING STATIONS - DC-6/7 AIRCRAFT INSPECTIONS
WING DESCRIPTION INSPECT COMMENTS INSPECTION REMARKS
STATIONS FOR TOOLS W.S. Flap trailing edges Warpage Outside Visual (1) Excessive warpage may 63 - surface cause flight control 421 inspection problem.
(2) Particular attention should be given this area.
W.S. Flap structure damage Cracked None Visual (1) Damage is usually 63 - ribs, clips caused during ground 421 skin, and operation.
loose rivets (2) This area should receive frequent inspections.
NOTE: Refer to manufacturer's repair manual and service bulletins for detailed repair instructions.
8/24/67 AC 20-52
AC 20-52 Appendix 6 8/24/67 Page 1 APPENDIX 6.
DC-6 AIRCRAFT MAINTENANCE INFORMATION. The following is a listing of significant maintenance difficulties that have been reported by air carriers as mechanical reliability reports from 1964 to 1967.
This information may be useful in identifying additional structural inspection areas:
a. Wings.
(1) During an overhaul inspection, the main landing gear outer cylinder, P/N 8065H2, was found cracked in the radius area of the outside diameter of the cylinder just below the 'y" Repairs were accomplished in accordance with the manufacturer's instructions. The aircraft total time was 25,000 flight hours. This same condition was found on another aircraft having 31,000 flight hours.
Cracks were found in the trunnionbore of the left and right front spar main landing gear drag strut fitting. The drag strut fitting was replaced. The aircraft total time was 49,786 flight hours.
(3) During inspection, the right wing flap strut assembly link support, P/N 5329694, located at W.S. 167 was found cracked at the aft end. The flap support was replaced. Time since the last inspection was 509 hours.
(4) During landing, the left wing flap was damaged. Investigation revealed that the left outboard hinge bracket assembly, P/N 3365189, was broken. The bracket was replaced.
(5) A two-inch crack was found in the upper wing skin. The crack was located at W.S. 96, inboard of the No. 3 nacelle in the aft corner of the tank access hole. The aircraft total time was 25,208 hours.
(6) During inspection, the right and left flap hinge fittings were found cracked in the inboard web at the radius of the hinge hanger cutout at W.S. 167. Hinge fittings, P/N 5492213- 13 and -14 were replaced. Aircraft total time was 19,783 hours.
During a basic service check, the left front spar drag fitting, P/N 5325648, was found to be cracked. The crack ran from the drag strut fitting cutout, inboard and parallel with the front spar, approximately two and one-half inches below the inboard lug. The crack was approximately three inches long. The total time on the aircraft was 30,609 flight hours. The manufacturer has issued rework instructions including repetitive inspections at 100-hour intervals.