AIRCRAFT SPECIAL INSPECTIONS

SPECIAL INSPECTIONS

Life rafts in storage or in service shall be unpacked and thoroughly inspected for mildew whenever weather or other conditions warrant. The ex­tent of a special inspection will be determined by the inspector or maintenance chief follow­ing a review of the circumstances or conditions to which the life rafts have been subjected. The inspector or maintenance chief may direct a complete overall inspection and inflation test of the life rafts, regardless of the last date of inspection, if it is considered that another in­spection is warranted.

INSPECTION RECORD

The date the inspection was completed will be stencilled on the flotation tube at the left of the cylinder. The size of lettering will not be less than 1/4-inch or greater than 1/2-inch in height. Previous inspection dates will not be removed or obliterated, but will be arranged in colum­nar form with the latest date at the top. After the inspection is completed, fill out the raft's in­spection record in accordance with part 43 sec­tion 43.9, and attach the parts tag to the survival equipment. The date on the tag will reflect the same date as stenciled on the flotation tube and will be used to determine the next due date of inspection and test.

RAFT REPAIRS

Repairs. The service life for flotation equipment will be determined by condition rather than age. Equipment passing tests and inspections may remain in service indefinitely since the inflation tests and material inspec­tions will identify and condemn equipment having more than minor installation defects. However, the service life for life rafts operat­ing under normal usage and environmental conditions is anticipated by the manufacturers to be 8 to 10 years, and it is appropriate to base life raft's parts replacement programs upon this estimate. It is not considered advisable or economical to perform major repairs on life rafts.

Life Rafts.       Life rafts with any of the following conditions should be condemned rather than repaired:

(1)       Life rafts over 3-1/2 years of age and requiring major repair or more than two miⁿor repairs.

(2)       A rip or tear across an air retaining seam.

(3)       Rafts on which oil, grease, or any other foreign substance has caused a deteriora­tion of the rubberized fabric.

(4)       Rafts on which a heavy mildew condition has caused deterioration of the rub­berized fabric.

(5)       Rafts on which porous flotation tubes allow diffusion of air. A porous area is located by a soap test on the inflated raft. Higher diffusion is indicated by the excessive loss of pressure after a soap test has failed to locate a specific area of injury on the raft.

(6)       Rafts requiring internal repair or opening of air retaining seams for repair.

(7)       Rafts with an excessive number of injuries that would not, in the judgment of competent inspectors, justify repair.

Patches. Holes or abrasions which are 2 inches or less, in diameter_. (in air retaining chambers) will be repaired by the application of an outside patch. Holes exceeding 2 inches in length or diameter, will require an inside patch as well as an outside patch. Inside and outside patches should be round or rectangular and manufactured of fabric (specification MIL-C-6819). Cement should conform to Class 1 of specification MIL-C-5539. Patch as follows:

(1)       Outside patches.

(a)       With a rubber solvent thoroughly clean the area to be patched.

(b)       From the material referenced, fabricate a patch.

(c)       When two fabric surfaces are to be bonded, apply two coats of extra light ce­ment, two coats of light cement, and three coats of heavy cement to each surface. Rubber coated tape and seam crossover patches with protective backing do not require cement. Each coat of cement should be thoroughly dry to the touch before the next coat is applied. Start the bonding of fabric surfaces while the last coat of cement is slightly tacky. To ensure proper adhesion when bonding two cemented sur­faces, the areas to be bonded should remain tacky during application. This is accomplished by brushing the cemented area with a cloth moistened with solvent.

NOTE: If difficulty in the drying of heavy cement is encountered due to atmospheric conditions, six additional coats of light cement may be substi­tuted for the three coats of heavy ce­ment.

(d)       After applying the patch, thor­oughly roll it with a hand roller, rolling from the centre to the outer edge, to ensure that all air pockets are removed and a firm bond is se­cured.

(e)       Thoroughly dust with talc. Allow to cure for 60 hours before performing leak tests and storing.

(2)       Inside Patches.

(a)       Cut a rectangular patch , allowing at least 1-1/2 inches to extend beyond the edge of the injury in all di­rections.

(b)       Mark the centre line on the side of the patch that is to be attached to the raft. Mark cross lines on each end of the patch l-1/2 inches from the ends. When the patch is applied to the injury on the inside, the longitu­dinal edges of the injury will coincide with the centre line, and cross lines on the ends of the patch will coincide with the ends of the injury.

c)         To ensure that the inside surface of the raft is properly powdered in the area of repair, pass a small handful of talc through the opening in the raft and place it approximately 12 inches from the injury. This should be ac­complished before the inside area is cemented, exercising care to prevent distribution of the talc prior to completion of the repair.

(d)       Using cleaning solvent, cleanse an area on the inside surface of the fabric slightly larger than the patch to be applied. En sure that the repaired area is thoroughly dry, both inside and outside; apply two coats of extra light cement, two coats of light cement, and three coats of heavy cement (or six addi­tional coats of light cement in lieu of the heavy cement) to the cleansed area, allowing each coat to dry thoroughly before applying succes­sive coats.

NOTE: Since it is impossible for the repairman to visually observe the ce­menting     that is being accomplished on the inside of the raft, exercise care to ensure that each coat of cement com­pletely covers the area to be repaired.

(e)       The inside patch should be ce­mented simultaneously with the application of cement to the inside of the raft. Apply the same number of coats as directed in para­graph 9 42b(2)(d) to the side of the patch that is applied to the injured fabric of the raft. En­sure that each coat is thoroughly dry before applying the next coat.

(f)        To aid in adhesion, prior to ap­plying the patch, the inside area to be repaired and cemented surface of the patch should be cleaned with a cloth moistened with rubber solvent. The cement will then become tacky.

(g)       Apply the patch. Fold the patch lengthwise in the shape of the letter "U" and insert the patch between the. tom edges of the injury on the life rafts. Position the patch so that the fabric at the end of the tear will coin­cide with a cross line and the centre line on the patch follows one edge of the torn fabric. At­tach one edge of the torn fabric along the centre line on the patch.

(h)       Inspect the repair for wrinkles. Working from the attached edge of the fabric to the edge of the patch, remove the wrinkles with_. a stitcher. Lay the opposite edge of the torn fabric on the patch so that it butts the edge of the torn fabric that has already been applied to the patch. Remove the wrinkles. Thor­oughly roll the patch with a 2 inch rubber roller.

          NOTE: The surface under the patch should be as smooth as possible so that the torn edge of the fabric may be at­tached to the patch instead of at­tempting to attach the patch to the fabric.

(i)         Scatter the handful of talc that was placed inside the tube by grasping the sides of the flotation tube and pulling them apart.

(j)         Prepare and attach the outside patch as outlined in "OUTSIDE PATCHES," sub-paragraphs 9-42b(1)(a)-(e).

(k)       Allow to cure for at least 60 hours before performing leak tests and storing.

(3)       Seams and Tapes.

(a)       Remove all old or dead cement from the area that will require re-cementing. Dampen the repair area with a solvent moistened cloth; then roll or rub off the old cement.

(b)       Apply cement to the surface as outlined in "OUTSIDE PATCHES," sub­paragraph 6.6.2(1), 6.6.3(a)-(e).

(c)       Roll thoroughly with a roller to ensure that all air pockets are removed and a firm bond is secured.

(d)       Allow to dry and apply talc over the seam as previously outlined.

(e)       Allow to cure for at least 60 hours before performing leak tests and storing.