Vulcanized Repairs; Deicer Installation; Preparation Of Leading Edges; Mounting Deicer On Leading Edge - Piper Navajo Chieftain PA-31-350 Service Manual

NAVAJO CHIEFTAIN SERVICE MANUAL
e. DAMAGE TO FABRIC BACK PLY OF DEICER DURING REMOVAL. If cement has pulled
loose from the wing skin and adhered to the back surface of the deicer, remove it with clean rags and MEK.
In those spots where the coating has pulled off the fabric, leaving bare fabric exposed, apply at least two
additional coats of cement, Part No. 74-451-24. Allow each coat to dry thoroughly.
14-78. VULCANIZED REPAIRS. Due to the varity of boot damage possible, it is recommended that the
B. F. Goodrich Company be contacted so they can determine the extent of damage and whether it is
repairable by the vulcanized method, or not. The overall condition of the deicer boot must be given careful
consideration before deciding on any repairs. Damages can vary from minor punctures which may be easily
repaired, to extensive ripping of the tube or stretch areas which may make repairs exceedingly difficult or
actually impossible. The determination of just where this division between repairable and unrepairable
damage exists will depend upon the careful judgment of the inspector. For this reason, we recommend
contacting the B. F. Goodrich Company, at Akron, Ohio.
14-79. INSTALLATION. The following procedure for installing deicers assumes that the airplane has
provisions for air connections, etc.
14-80. PREPARATION OF LEADING EDGES. If the leading edges are painted. remove all paint
including zinc chromate primer.
a.
With one inch ( I ) masking tape. mask off leading edge boot area. allowing 1 2 inch margin for
non-recessed boots. Take care to mask accurately. thus eliminating the need for cleaning off excess cement
later.
b.
Clean the metal surfaces thoroughly. at least twice. with MEK or acetone. For final cleaning.
solvent film off quickly with a clean dry cloth before it has time to dry.
NOTE
It is permissible to install deicers on alodined or anodized surfaces.
c.
Fill gaps of skin splices that lead under deicers with sealing compound EC-801.
d.
Remove the summper plugs from the air connection grommets. In some cases, it will be necessary
to remove sections of doped fabric used to cover the air connection holes. Draw out the ends of the
non-kink hose section so that they protrude through the connection holes in the leading edge. If hose is
cracked or deteriorated, replace with new hose.
14-81. PREPARATION OF DEICER. Moisten a clean cloth with MEK or acetone and carefully clean the
rough. back surface of the boot at least twice. Change cloths frequently to avoid recontamination of the
cleaned areas.
14-82. MOUNTING DEICER ON LEADING EDGE. Thoroughly mix EC-1300L cement before using.
Apply one even brush coat to the cleaned back surface of the boot and to the cleaned metal surface. Allow
the cement to air dry for a minimum of one hour. Apply a second coat to both surfaces and allow to air dry
a minimum of one hour. Ambient temperature for installation should be held between 40
°
and 110
°
F.
However, longer drying time of the cement coats may be required as the humidity approaches 99%. Deicer
and leading edge may be cemented for a maximum of 48 hours before actual installation, if cemented parts
are covered and kept clean.
Snap a chalk line along the leading edge of the airfoil section. Intensify chalk line on leading edge and
the white reference line on the boot with a ball point pen. Most boots are made with an excess of material
at the inboard and outboard edges for final trimming after installation and some recessed boots trim on the
upper and lower edges.
Securely attach hose to deicer connections using clamps or safety wire.
Reissued: 9/23/80 ACCESSORIES AND UTILITIES
4G7