PAGE14 51-20-00
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PIPERAIRCRAFT
PA-42-720(AdvancedTrainer)
MAINTENANCEMANUAL
A Processes(continued)
2. Avionicsand ECU Bay DoorSealing
(a) Avionicsand ECU Bay DoorSealsRemoval
1. Apply mineralspiritsto seal to loosen adhesive. Usinga plastic scraperor other
appropriateinstrument,scrapeoff seal while applying mineral spirits, as necessary,to dissolveadhesive.
2. Withseal removed,use a clean cloth and mineralspiritsto remove all excess adhesive.
(b) Avionicsand ECU Bay Door Seals Installation
1.
Clean door frame using a clean clothand Prep-Sol, or a similar cleaner whichwill not leavean oily residue.
2.
Orient seals on the frame asfollows. Markthe seal mating surface:
(a)
Aft -56598-06
(b)
Top-56598-07
(c)
Forward-56598-08
(d)
Bottom-56598-09
3.
Coat seal matingsurfacesand the bay frameface with 3M 1300L contactcement. Allow to dry 15 minutes.
4.
Installsealsin their appropriate locations.
(c) Avionics and ECU BayDoor Camloc FastenersSealing
Seal camloc fastenerreceptacleson backside of the bay frame as follows(referto Figure 209):
1.
Apply PRC 1221 Type B-2 sealant aroundreceptacleperimeter, over rivet bucked tails, and around baseof the receptacle'scenterpart.
2.
Slip a sleeve capover center part of receptacle. Seat it firmly in sealant around base. Allowto cure properly.
3.
Seal receptacle holes in the face of the bay door frame. (Shownin Figure 209)
Seal all seams Sealant between skins and between skin and
Sleeve
Cap
Door Frame Receptacle
Avionicsand ECU Bay Door Sealing
Figure209
EFFECTIVITY:
040-999
51-20-00
Jan 10/90
PIPERAIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCEMANUAL
Fasteners
A. RivetReplacement WARNING: UNDER NO CIRCUMSTANCES CAN A RIVET BE REPLACED WITH ONE OF LOWER STRENGTH. Whenever possible, rivets must be replaced with the same size and strength originally specified.
However, when a rivet hole is enlarged, deformed or damaged, increase hole size and replace the original with an oversize rivet, specified in this manual. It is acceptable, however, to replace 2117-T3 rivets with either 2017-T4 or 2024-T4 rivets, providing the
spacings and edge distances of Chart 801 are maintained.
CHART 801
EDGE DISTANCE AND SPACING vs RIVET DIAMETER
RIVET EDGE DISTANCE SPACING
DIAMETER 2D 2D1/16 3D 4D 5D 6D 1/16 .125 .188 .188 .250 .313 .375 3/32 .188 .250 .281 .375 .469 .563 7/64 .219 .281 .328 .438 .547 .656
1/8 .250 .313 .375 .500 .625 .750 9/64 .281 .344 .422 .563 .703 .844 5/32 .313 .375 .469 .625 .781 .938
11/64 .344 .406 .516 .688 .859 1.031 3/16 .375 .438 .563 .750 .938 1.125
CHART 802
ACCEPTABLE RIVET SUBSTITUTES
SPECIFIED RIVET REPLACEMENT RIVET
2117-T3 2017-T4 2024-T4
MS20426-AD MS20426-D MS20426-DD
MS20470-AD MS20470-D MS20470-DD
EFFECTIVITY:
040-999
51-40-00Jan 10/90
PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCE MANUAL
B. Oversize Rivet Replacement
When a rivet hole is enlarged, deformed or damaged the hole size can be increased and the original rivet replaced with an oversize rivet, according to the following limitations:
1. The enlarged, finished hole must be smooth and free of defects.
of Chart 801.
2.
The larger rivet diameter must meet the edge distance and spacing requirements
3.
In the case of a 1/64" oversize flushrivet, the countersink or dimple is acceptable without rework
4.
In the case of a 1/32" oversize flush rivet, the hole must be countersunk or dimpled.
5.
Blind rivets with aluminumspindles,which have an oversized hole, may be replaced by oversize cherry-maxblind rivets, providing hole standards conformto Chart 803 (use CR3243 for protruding head and CR3242 for flush head).
CHART 803
SPECIFICATION FOR REPLACEMENT OVERSIZE RIVETS
PROTRUDING HEAD RIVETS
SPECIFIED RIVET OVERSIZED REPLACEMENT RIVET
STANDARD DIA. 1/64" OVERSIZE DIA. 1/32" OVERSIZE DIA.
MS20470-AD3 3/32 NAS1242-AD3 7/64 MS20470-AD4 1/8
MS20470-AD4 1/8 NAS1242-AD4 9/64 MS20470-AD5 5/32
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