Protect fuel cell at all times from
sharp objects and from extremes
of temperature and humidity.
cells shall not be folded and/or
collapsed for periods of more
than four (4) hours. Fuel cells
must be supported when stored,
shipped, and/or repaired.
Preservation of a fuel cell shall be
completed, unless it will be more
than 30 days before repairs are
started. This reduces the cleanup
effort by repair personnel prior to
paragraph 2-5f (5) for preservation
The following repair criteria and
procedures apply to self-sealing,
crash resistant fuel cells.
Classify fuel cell damage as follows:
Minor damage. See table 2-5 for serviceable limits.
(a) Internal Blister Damage.
Blisters exceeding 1/4 inch diameter must be repaired.
Cut blister(s) open, remove fluid in blister, dean, buff,
dean, cement loose blister material down, and apply an
(b) Internal and External Loose Seam
(Lap or Splice, Edge, or Fitting Flange) Damage.
Refers to loose edge of lap splice, reinforcement ply, or
fitting flange. All loose seams/edges of lap splices,
reinforcement plies, or fitting flanges (exposed edge on
interior or exterior surface of cell) with up to 1/4 inch of
material missing can be cleaned, buffed, cleaned,
cemented and the repair rolled with a roller. For seams
and splices with up to 2 square inches of material
missing or fitting flanges with 1/4 inch minimum to 1/2
inch maximum of material missing or otherwise
damaged, a patch repair is required.
(c) Cuts, Tears, Chafing, Scuffs or
Snag Damage. All cuts, tears, chafing, scuffs or snags
occurring to the innerliner or outerply, where the coating
is missing or cord/fabric is exposed but not tom, can be
buffed and cemented, and allowed to air dry 8 hours.
All cuts, tears, chafing, scuffs, or snags, less than 2
inches in length or area, occurring to the innerliner,
where fabric is torn/cut require an internal patch repair.
(d) Hole or Cut 1/8 Inch or Less in
Diameter in External Surface or Penetrating the Entire
Cell Wall. No sealant activation is allowed.
(e) Loose or Separated Hanger or
Loop. Loose or separated hangers or loops can be
cleaned, buffed, cleaned, and cemented back in place.
Inserts (Helicoils). CTM 1-1500-204-23-6).
(g) Fitting Damage/Finish. Fittings
which have inter-crystalline corrosion or scratches,
outside of the critical sealing surface, to a depth of .030
inch can be reworked.
Non-Repairable Damage. Damage that is not
reparable is classified as follows:
Damage which extends into a comer
Damage which has led to activation of the
Cuts or tears longer than 2 inches and any
damaged area larger than 2 square inches.
A hole larger than 1/8 inch in diameter
which penetrates the entire cell wall (through hole).
A hole which penetrates beyond the
exterior surface ply larger than 1/8 inch in diameter.
External blister damage.
Damage to fitting O-ring groove and
damage inside of the critical sealing surface. Also,
damage within 1/4 inch of O-ring grooves, bolt holes,
etc. inside or outside of critical sealing surface is not
Change 2 2-56