Cleaning, Inspection And Repair Of Fuel Cells - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
e.
Remove the filler cap and machine screws that secure the cap adapter and gasket.
f.
Place tape or another protective material around the cell access opening to prevent damage to the
cell when removing it.
g.
Fold the cell neatly within the nacelle and remove it gently through the cell access opening located
in the forward end of the nacelle baggage compartment.
9-6. CLEANING, INSPECTION AND REPAIR OF FUEL CELLS.
a.
Fuel cells may be cleaned by the following procedure:
1.
New Cells: It should not be necessary to clean new cells upon removing them from their
containers, if they are installed in the airframe cavities promptly. If for any reason the cells are not installed
immediately, and become dirty, they should be cleaned with soap and warm water to remove foreign
material prior to installation in a clean cavity.
2.
Used Cells: Prior to removal, the cells are to be drained of fuel, purged with fresh air and
swabbed out to remove all traces of fuel. Following removal, the cells are to be cleaned inside and out with
soap and warm water.
WARNING
Use a vapor-proof light for inspection.
NOTE
To determine if fuel cell is repairable, reach through the fuel cell
access plate and take a section of cell between thumb and
forefinger. Wipe the ridge created by this action with MEK. If fine
cracks are evident, the fuel cell is not repairable.
b.
Fuel cells may be inspected by the following procedure:
1.
New Cells: Inspect the cell surface inside and outside for cuts, abraded (scuffed) areas and
accessory damage. Also, inspect the fitting seals for nicks, scratches and foreign material.
2.
Used Cells: Cells removed from the airframe cavity for inspection and repair or cells being
returned to service from storage, should be inspected as outlined above. Cells installed in the airframe cavity
may be inspected for possible repairs by reaching through the fuel cell access plate and taking a section of
cell between the thumb and forefinger. Wipe the ridge created by this action with MEK. If fine cracks are
evident, the fuel cell is not repairable.
3.
Baffled Fuel Cells: Inspect every 2 years by conducting the following inspection:
(a) Defuel both main cells. (Refer to Section II.)
(b) Remove the access plates located inboard of the nacelle. Remove both wing and fuel
cell access plates.
(c) Inspect fuel cell fittings for deterioration of the rubber used, using the fingernail to
attempt to scrape the rubber off the metal or nipple fitting. If the rubber has not
deteriorated, the fingernail will glide across the rubber. If a degraded condition exists
the fingernail will dig into the rubber. Usually the deteriorated rubber will have
changed from a light yellowish-tan to a dark reddish brown.
(d) Check the tension and knots of the two nylon support cords.
(e) Inspect the interior of the cell for security of baffle and the free operation of the
flapper valve. Inspect both sides of the baffle.
(f) Inspect the exterior of the cells to insure the Velcro tape has not parted from the cell
surface or liner surfaces.
(g) Install all access plates on fuel cells and wings. Fill cells and check for leaks.
Revised: 10/5/83
FUEL SYSTEM
2K8