Installation Of Wing Tip Tanks; Removal Of Wing Fuel Cells - Piper Cheyenne IIIA Airplane Maintenance Manual

PIPER AIRCRAFT
PA-42-720 (Advanced Trainer)
MAINTENANCE MANUAL
A. Storage (continued)
6. Installation of Wing Tip Tanks (refer to 28-10-00 Figure 401)
(a) Connect tank to wing by installing six bolts.
(b) Connect all plumbing to tank.
(c) Install sender unit and connect electrical leads to navigation lights and strobes.
(d) Install fairing between wing tip and tip tank.
7. Removal of Wing Fuel Cells (refer to 28-10-00 Figures 402, 403, and 404)
(a) Drain both systems when removing cells on both sides. If only one side is affected, or when
replacing or servicing main inboard fuel cell, close crossfeed valve and drain appropriate tank
or system.
(b) Remove necessary access plates on wing to gain access to fuel cell and senders. When
removing inboard main fuel cell, remove forward bottom wing root and fuel cell drain panels
and plates.
(c) Inboard and outboard main fuel cells interconnect, where applicable, with nacelle tank, wing,
and vent system through fittings mounted in wing skin located under nacelle. When removing
tanks, remove top center panel on nacelle to make access to fittings. Remove bolts attaching
fittings to wing and all hardware from affected tank.
(d) Disconnect wires from appropriate senders, remove screws securing each sender to fitting, and
carefully withdraw sender with its gasket from cell. Note position of each gasket relative to
sender unit when removing, to facilitate reinstallation.
(e) Reach through appropriate access hole. Loosen and disconnect clamps from nipples and
interconnecting tubes. If replacement of tubes is necessary, remove from wing by
disconnecting each tube ground strap from spar and from other tank.
(f) On underside of wing, remove screws mounting quick drain plates to wing. Carefully draw two
fuel cell drains out of wing. (Enough to allow screwdriver to release clamps.)
CAUTION: TO PREVENT NYLON FITTING FROM TURNING WHEN DISCONNECTING
ELECTRICAL CONNECTION ON FUEL PUMPS, A WRENCH MUST BE USED
TO BACK UP EACH CONNECTION ON TANK. IF FITTING TURNS, INTERNAL
WIRE CONNECTIONS WILL BREAK AND PUMP MUST BE REPLACED.
(g) When removing inboard main fuel cell, remove electrical connections from fuel pump in cell and
disconnect and cap fuel lines.
(1.) Withdraw pump from tank by removing four bolts mounting pump to tank and wing rib. Lift
pump through access hole in wing.
CAUTION: DO NOT DAMAGE SMALL FLAPPER VALVE IN INTERIOR BAFFLE, NEXT TO
FUEL PUMP MOUNTING LOCATIONS, WHEN REMOVING MAIN INBOARD
FUEL CELLS.
(h) Reach through proper access hole for each fuel cell. Untie nylon cord securing each cell.
(i) Remove all cap bolts at access holes attaching cells to skin brackets. Push cell down and work
nylon cord back through cell hangers and rib bushings to ends of cell compartment.
(j) Remove screws attaching mounting brackets to wing skin in each elongated access hole.
Remove brackets from holes.
(k) Place tape or other protective material around cell access opening, preventing damage to cell
during removal.
(I) Fold cell neatly in wing; tape or tie. Remove cell gently through elongated opening on top of
wing.
EFFECTIVITY:
040-999
PAGE 6 28-10-00
Jan 10/90