AC 43.13-1A Page 153 1972 Section 3. MISCELLANEOUS EQUIPMENT
360. PARACHUTES. With reasonable care, parachutes normally last at least 5 years. They should not be carelessly tossed about, left in airplanes so that they may become wet, or left in open places where they may be tampered with. They should not be placed where they may fall on oily floors or be subject to acid fumes from adjacent battery chargers. When repacking is scheduled, a careful inspection of the parachute should be made by a qualified parachute technician (rigger). If repairs or replacements of parts are necessary to maintain the airworthiness of the parachute assembly, such work must be done by the original parachute manufacturer or by a qualified parachute rigger, certificated in accordance with Part 65 of the Federal Aviation Regulations, or by an appropriately rated parachute loft certificated in accordance with Part 149 of the FAR.
361. SAFETY BELTS, The Civil Air Regulations require that when safety belts are to be replaced in aircraft manufactured after July 1, 1951, such belts must conform to standards established by the Federal Aviation Administration. These standards are contained in Technical Standard Order TSO-C22. Safety belts eligible for installation in aircraft may be identified by the marking TSO-C22 on the belt or by a military designation number since military belts comply with the strength requirements of the TSO. Airworthy type-certificated safety belta currently in aircraft may be removed for cleaning and reinstalled. However, when a type-certificated safety belt is found unairworthy, replacement with a TSO-C22 or a new milltary belt is preferred.
a. The webbing of safety belts, even when mildew-proofed, is subject to deterioration due to constant use, cleaning, and the effects of aging. The clamping action of the serrations of the commonly used buckle also causes a reduction in strength of the webbing and fraying occurs after long periods of usage. Praying of belts is an indication of wear, and such belts are likely to be unairworthy because they can no longer hold the minimum required tensile load. Difference of opinion as to the airworthiness of a belt can be settled by testing a questlonable belt to demonstrate that it will support the required load. Airworthy one-person type-certificated belts should be able to withstand a tensile load of 525 pounds, and TSO belts withstand the rated tensile load indicated on the belt label. Most one-person TSO belta are rated for 1,500 pounds, For two-person belts, double the loads. Since type-certificated belts will not afford the crash protection provided by a TSO or military belt, such type-certificated belts are not to be repaired nor should their buckles or end fittings be reused on safety belts. If replacement oi webbing or hardware of TSO or military belt is attempted, use parts of identical design and material. Make the stitch pattern identical to the original and the number of stitches per inch equal to the number used in the original belt.
There is no objection to having a greater total length of stitching, provided one line of stitches is not placed over another line. Space lines of stitching at least 8/16-inch apart. Keep a record, preferably in the logbook, stating the extent to which the belt was repaired and the date. Retain the original identification marking on the belt, conforming either to that required by TSO-C22 to a deviation from this marking, or to the military designation. Operators of a fleet of airplanes should follow the above suggestions, but keeping a record of renovations in a logbook is impractical, since the belts are never associated with any one particular aircraft for any length of time. Therefore, in addition to retaining the original identification label and attaching it to the renovated belt, use some additional simple marking to indicate Chap • Par 360
that the belt has been renovated and show the date of renovation. The use of letter "R" followed by the date would be acceptable. This marking could be in the form of an indelible ink stamping or cloth label stitched to the webbing.
362. FLARES. Parachute flares are made of materials which are subject to decomposition upon aging. Humidity affects the small igniting charge and also the materials of the candle (illuminant). Hence, the percentage of misfires in old flares is likely to be quite high. To assure inspect the fore installat on foeperiode entire system, starting at the release mechanism in the cockpit and ending at the flare. Only a qualified person should attempt such inspection, since inadvertent discharge of such pyrotechnics may cause serious damage. Past experience has indicated that it is advisable to return all electrically or pistol-operated flares to the manufacturer for reconditioning within a maximum period of 8 years, and that for mechanically operated flares, a maximum period of 4 years is recommended.
363. OXYGEN SYSTEMS.
a. General. The following instructions are to serve as a guide for the inspection and maintenance of aircraft oxygen systems. The information is applicable to both portable and permanently installed equipment.
(1) Aircraft Gaseous Oxygen Systems. The oxygen in gaseous systems is supplied from one or more high- or low-pressure oxygen cylinders. Since the oxygen is compressed within the cylinder, the amount of pressure indicated on the system gauge bears a direct relationship to the amount of oxygen contained in the cylinder. The pressure-indicating line connection is normally located between the cylinder and a pressure-reducing valve.
NOTE: Some of the gaseous oxygen systems do not use pressure-reducing valves. The high pressure is reduced to a useable pressure by a regulator. This regulator is located between the high- and low-pressure system.
(2) Alreraft Liquid Oxygen Systems, Thus far it has not been a practice to use liquid oxygen in Par 361 AC 43.13-1A 1972 civil aircraft due to its complexity. This however, may change at any time as technological advances are made.
(3) Portable Oxygen Systems. The three basic types of portable oxygen systems are: demand, pressure demand, and continuous flow. The component parte of these systems are identical to those of a permanent installation with the exception that some parts are miniaturized as necessary. This is done in order that they may be contained in a case or strapped around a person's shoulder. It is for this portability reason that it is essential special attention be given to assuring that any storage or security provision for portable oxygen equipment in the aircraft is adequate, in good condition, and accessible to the user.
Nore: Check portable equipment including its security provisions frequently, as it is more susceptible to personnel abuse than a permanently installed system.
b. Inspection. Handa, clothing, and tools must be free of oil, grease, and dirt when working with oxygen equipment. Traces of these organic materials near compressed oxygen may result in apontaneous combustion, explosions, and/or fire.
(1) Oxygen Tanks and Cylinders. Inspect the entire exterior surface of the cylinder for indication of abuse, dents, bulges, and strap chating.
(a) Examine the neck of cylinder for cracks, distortion, or damaged threads.
(b) Check the cylinder to determine if the markings are legible.
(c) Check date of last hydrostatic test. If the periodic retest date is past, do not return the cylinder to service until the test has been accomplished.
NorE: This test period is established by the Department of Transportation in the Code of Federal Regulations, Title 48, Chapter 1, Paragraph 178.84.
(d) Inspect the cylinder mounting bracket, bracket hold-down bolts and cylinder holding straps for cracks and deformation, cleanliness, and security of attachment.
(e) In the immediate area where the cylinder is stored or secured, check for evi- Chap 8
AC 43.13-1A 1972 dence of any types of interference, chafing, deformation, or deterioration.
(2) Lines and Fittings.
(a) Inspect oxygen lines for chafing, corrosion, flat spots and irregularities, i.e., sharp bends, kinks, and inadequate security.
(b) Check fittings for corrosion around the threaded area where lines are joined together. Pressurize the system and check for leaks. (Ref. c(2) (b) 4.)
CAUTION In pressurizing the system, actuate the valve slowly to avoid surging which could rupture the line.
(3) Regulators, Valves, and Gauges.
(a) Examine all parts for cracks, nicks, damaged threads or other apparent damage.
(b) Actuate regulator controis and valve to check for ease of operation.
(c) Determine if the gauge is functioning properly by observing the pressure build-up and the return to zero when the system oxygen is bled off.
(4) Masks and Hoses.
(a) Check the oxygen mask for fabric cracks and rough face seals. If the mask is a fullface model, inspect glass or plastic for cleanness and state of repair.
(b) When appropriate, with due regard to hygienic considerations, the sealing qualities of an oxygen mask may be tested by placing thumb over connection at end of mask tube and inhaling very lightly. Remove thumb from diaconnect after each continuous inhalation. If there is no leakage, mask will adhere tightly to face during inhalation and definite resistance to inhalation will be noticeable.
(c) Flex the mask hose gently over its entirety and check for evidence of deterioration or dirt.
(d) Examine the mask and hose storage compartment of cleanliness and general condition.
(e) If the mask and hose storage compartment is provided with a cover or release mechanism, check its operation.
c. Maintenance.
(1) Oxygen Tanks, Cylinders, and Hold Down Brackets.
Chap 8 Page 155
(a) Remove from service any cylinders that show signs of abuse, dents, bulges, cracks, distortion, damaged threads, or defects which might render the cylinder unsafe. Typical examples of oxygen cylinder damage are shown in figure 8.7.
DENT
AVIATORS BREATHING OXYGEN THREAD DAMAGE CRACKS FIGURE 8.7.--Oxygen cylinder damage.
(b) When replacing an oxygen cylinder, be certain that the replacement cylinder is of the same size and weight as the one removed.
Nore: Cylinders having greater weight or size will require strengthened cylinder mounting brackets, and a reevaluation to determine that the larger or heavier cylinder will not interfere with adjacent systems, components, or structural members, and that the strength of attaching structure is adequate.
(c) Replace or repair any cylinder mounting brackets that show sign of wear. Visible cracks may be welded in accordance with Chapter 2, Section 2 of this Advisory Circular.
Replace cylinder straps or clamps that show wear or abuse. For typical mounting bracket crack and failure, see figure 8.8.
poked racket it
(b) Clean oxygen system fittings showing signs of rusting or corrosion in the threaded area. To accomplish this, use a cleaner recommended by manufacturers of oxygen equipment. Replace lines and fittings that cannot be cleaned.
1. The high-pressure lines which are located between the oxygen bottle, outside oxygen service filler, and the regulator are normally fabricated from stainless steel or thickwall, seamless copper alloy tubing. The fittings on high-pressure lines are normally silver sol- Par 363
Page 156 AC 43.13-1A 1972
CHECK FOR LOOSE RIVET
CHECK HOLDING CLAMPS
FOR IRREGULARITIES
CHECK FOR CRACKS
IN COVER PLATE
CHECK FOR CRACKS FIGURE 8.8. Cylinder brackets and clamps.
NOTE: Use silver alloys free of cadmium when silver soldering. The use of silver solder which contains cadmium will emit a poisonous gas when heated to a molten state. This gas is extremely hazardous to health if inhaled.
2. The low-pressure lines extend from the pressure regulator to each passenger and crew oxygen outlet. These lines are fabricated from seamless aluminum alloy, copper, or flexible hose. Normally, flare- or flange-type connections are used. (Ref. Chapter 10, Section 1, para. 398b of this Advisory Circular.)
CAUTION Do not allow ofl, grease, fammable solvent, or other combuatibles such as lint or dust to come in contact with threads or any parts that will be exposed to pressurized oxygen.
3. It is advisable to purge the oxygen system any time work has been accomplished on any of the lines and fittings. Use dry nitrogen or dry air for purging the system. All open lines should be capped immediately after purging.
4. When oxygen is being lost from a system through leakage, a sequence of steps may be necessary to locate the opening. Leakage may often be detected by listening for the distinct hissing sound of escaping gas. If this check proves negative, it will be necessary to soap-test all lines and connections with a castile soap and water solution or specially compounded leak-test material. Make the solution thick enough to adhere to the contours of the fittings. At the completion of the leakage test, remove all traces of the soap and water.
CAUTION Do not attempt to tighten any connections while the system is charged.
(3) Regulators, Valves, and Gauges. Line maintenance of oxygen regulators, valves, and gauges does not include major repair. These components are precision made and their repair usually requires the attention of a repair station or the manufacturer. Care must be taken when reinstalling these components to ascertain if the threaded area is free of nicks, burrs, and contaminants that would prevent the connections from sealing properly.
CAUTION Do not use petroleum lubricants on these components.
(4) Masks and Hoses.
(a) Troubleshooting. If a mask assembly is defective (leaks, does not allow breathing, or contains a defective microphone), it is advisable to return the mask assembly to the manufacturer or a repair station.
(b) Maintenance Practice and Cleaning.
1. Clean and disinfect mask assemblies after use, as appropriate.
NOTE: Use care to avoid damaging microphone assembly while cleaning and sterilizing.
2. Wash mask with a mild soap solution and rinse it with clear water.
Par 363 Chap 8
AC 43.13-1A 1972
3. To sterilize, swab the mask thoroughly with a gauze or sponge soaked in a water merthiolate solution, This solution should contain 1/5 teaspoon of merthiolate per 1 quart of water. Wipe the mask with a clean cloth and air dry.
4. Replace the hose if it shows evidence of deterioration.
5. Hoses may be cleaned in the same manner as the mask.
6. Observe that each mask breathing tube end is free of nicks, and that the tube end will slip into the cabin oxygen receptacle with ease and not leak.
d. Functional Testing After Repair. Following repair, and before inspection plates, cover plates, or upholstering are replaced, test the entire system.
(1) Open cylinder valve slowly and observe the pressure gauge on a high-pressure system.
A pressure of approximately 1,800 p.s.i. (at 70° F.) should be indicated on the gauge. (Cylinder pressure will vary considerably with radical temperature changes.)
(a) Check system by installing one of the mask hose fittings (minus the mask) in each of the cabin wall outlets to determine whether there is a flow. If a demand mask is used, check by breathing through the mask (if appropriate, clean mask according to Par. c(4)
(b)) to see whether there is a flow of oxygen.
(b) Check the complete system for leaks in accordance with the procedure outlined in c(2) (b) 4.
(e) If leaks are found, close the cylinder valve; open an outlet to reduce the pressure in the system to zero.
(2) A pressure drop check of the system may be made as follows:
(a) Open the cylinder valve and pressurize the system. Observe the pressure gauge (a pressure of approximately 1,800 p.s.i. at 70° F.
should be indicated). For the light weight ICC 8HT 1850 cylinders, pressurize the system to approximately 1,850 p.s.i. at 70° F.
(b) Close the cylinder valve and wait approximately 5 minutes for temperatures to stabilize.
Chap & Page 157
(c) Record the pressure gauge reading and temperature and after 1 hour, record the pressure gauge reading and temperature again.
(d) A maximum pressure drop of 100
p.s.i. is permissible.
NorE: Conduct the above tests in an area where changes of temperature will be less than 10° F. In the event that a change in temperature greater than approximately 10° F. occurs during the 1-hour period, suitable corrections would be required, or reconduct the test under conditions of unvarying temperatures.
e. Service Requirements-Oxygen Cylinders.
Standard weight cylinders must be hydrostatic tested at the end of each 5-year period. This is a Department of Transportation requirement.
These cylinders carry an ICC or DOT SAA 1800 classification and are suitable for the use intended. The lightweight cylinders must be hydrostatic tested every 3 years, and must be retired from service after 15 years or 4,380 pressurizations, whichever occurs first. These cylinders carry an ICC or DOT 8HT 1850 classification.
CAUTION Use only aviation breathing oxygen when having the oxygen bottle charged. MIL-O-27210C specifies that the moisture content of aviation breathing oxygen must not exceed 0.005 milligrams of water vapor per liter of gas at a temperature of 70° F.
and a pressure of 760 millimeters of mercury.
(1) Charging High-pressure Oxygen Cylinders.
The following are recommended procedures for charging high-pressure oxygen cylinders from a manifold system, either permanently installed or trailer mounted. Never attempt to charge a low-pressure cylinder directly from a high-pressure manifold system or cylinder.
la) Inspection. Do not attempt to charge oxygen cylinders if any of the following discrepancies exist:
1. Contaminated fittings on the manifold, cylinder, or outside filler valve. It in doubt, wipe with stabilized trichloroethylene; however, do not permit solvent to enter any internal parts. Let air dry.
2. Cylinder out of hydrostatic test date. DOT regulations require ICC or DOT SAA designation cylinders to be hydrostatic tested to 5/8 their working pressure, every 5 years. Cylinders bearing designation ICC or Far 363
DOT 8HT must be hydrostatic tested to 5/8 their working pressure every 3 years, and retired from service 15 years or 4,380 filling cycles after date of manufacture, whichever occurs first.
3. Cylinder is completely empty. Do not charge, as the cylinder must be removed, inspected, and cleaned.
(b) Charging.
1. Connect cylinder valve outlet or out~ side filler valve to manifold.
2. Slowly open valve of cylinder to be charged and observe pressure on gauge of manifold system.
3. Slowly open valve of cylinder on manifold system having the lowest pressure and allow pressure to equalize.
4. Close cylinder valve on manifold system and slowly open valve of cylinder having next highest pressure. Continue this procedure until the cylinder has been charged in accordance with e(1) (d), Table of Filling Pressures.
(c) Top-off.
After the cylinder has been filled in accordance with the filling table (shown under e(1)
(a)) :
1. Close all valves on manifold system.
2. Close valve on filled cylinder and remove the cylinder from the manifold.
3. Using leak detector, test for leakage around cylinder valve threaded connections. (If leakage is present, discharge oxygen and return cylinder to facility for repair.)
4. Let cylinder stabilize for period of at least 1 hour, and then recheck pressure.
5. Make any necessary adjustments in pressure.
(d) Table of Filling Pressures, Initial ami Preazure Filling
• F. (D.s.1.)
1,650 10 1,700 20 1,725 80 1,775 40 1,826 Par 363 AC 43.13-1A 1972 Initial Filling (°F., remi Preasure (D.s.t.)
50 1,875 60 1,925 70 1,975 80 2,000 90 2,050 100 2,100 110 2,150 120 2,200 180 2,250 Initial Temperature--Refers to ambient temperature in filling room.
Filling Pressure-Refers to the pressure to which aircraft cylinders should be filled. This table gives approximations only, and assumes a rise in temperature of approximately 25° F.
due to heat of compression. This table also assumes the aircraft cylinders will be filled as quickly as possible and that they will only be cooled by ambient air; no water bath or other Example: If ambient temperature is 70° F.
fill aircraft cylinders to approximately 1,975
p.s.i.-as close to this pressure as the gauge may be read. Upon cooling, cylinders should have approximately 1,850 p.s.i. pressure.
12) Charging of Low-Pressure Oxygen Systems and Portables. For recharging a low-pressure aircraft oxygen system, or portable cylinders, it is essential that the oxygen trailer or cart have a pressure-reducing regulator. Military types E-2 or C-1 reducing regulators are satisfactory. These types of regulators reduce the large cylinder pressure from 2,000 p.s.i. to a line pressure of 450 p.s.i.g. (A welding pressure reducing regulator is not satisfactory.)
CAUTION When refilling the low-pressure system or portable cylinders, open the oxygen filler tank valve slowly to allow the system or portable cylinders to be filled at a slow rate. After the refilling operation is completed, check for leaks with a leak detector.
If a leak is detected, paragraph c(2) (b) 4 should be referred to for corrective action.
364.-374. RESERVED.
Chap &
AC 43.13-1A Page 159 1972 Chapter 9. WINDSHIELDS, ENCLOSURES, AND EXITS Section 1. PLASTIC WINDSHIELDS AND ENCLOSURES
375. GENERAL. These repairs are applicable to plastic windshields, enclosures, and windows in nonpressurized airplanes. For pressurized airplanes replace or repair plastic elements in accordance with the manufacturer's recommendation.
a. Types of Plastics. Two types of plastics are commonly used in transparent enclosures of aircraft. These materials are known as acrylic plastics and polyester plastics.
new replacement or heat the whole panel and reform. When possible, cut and fit a new panel at ordinary room temperature.
b. In clamping or bolting plastic panels into their mountings, do not place the plastic under excessive compressive stress. It is easy to develop more than 1,000 pounds per square inch on the plastic by overtorquing a nut and bolt.
Tighten each nut to a firm fit, then back off one
376. REPLACEMENT PANELS. Use material equivalent to that originally used by the manufacturer of the aircraft for replacement panels.
There are many types of transparent plastics on the market. Their properties vary greatly, particularly in regard to expansion characteristics, brittleness under low temperatures, resistance to discoloration when exposed to sunlight, surface checking, etc. Information on these properties is in MIL-HDBK-17, Plastics for Flight Vehicles, Part II-Transparent Glazing Materials, available from the Government Printing Office. These properties have been considered by aircraft manufacturers in selecting materials to be used in their designs and the use of substitutes having different characteristics may result in subsequent difficulties.
377, INSTALLATION PROCEDURES. When installing a replacement panel, use the same mounting method employed by the manufacturer of the airplane. While the actual installation will vary from one type of aircraft to another, consider the following major principles when installing any replacement panel:
a. Never force a plastic panel out of shape to make it fit a frame. If a replacement panel does not fit easily into the mounting, obtain a
c. in bolt installations, use spacers, collars, shoulders, or stopnuts to prevent tightening the bolt excessively. Whenever such devices are used by the airplane manufacturer, retain them in the replacement installation. It is important that the original number of bolts, complete with washers, spacers, etc., be used.
When rivets are used, provide adequate spacers or other satisfactory means to prevent excessive tightening of the frame to the plastic.
d. Mount plastic panels between rubbed, cork, or other gasket material to make the installation waterproof, to reduce vibration, and to help to distribute compressive stresses on the plastic.
e. Plastics expand and contract considerably more than the metal channels in which they are mounted. Mount windshield panels to a sufficient depth in the channel to prevent it from falling out when the panel contracts at low temperatures or deforms under load. When the manufacturer's original design permits, mount panels to a minimum depth of 11/8 inch and with a clearance of 1/8 inch between the plastic and the bottom of the channel.
f. In installations involving bolts or rivets, make the holes through the plastic oversize 1/8 inch diameter and center so that the plastic will not Chap 9 Par 375
Page 160 AC 43.13-1A 1972
ALL THE STRAINS WHICH ORIGINALLY CAUSED CRACK ARE CONCENTRATED AT POINT 4)- TENDING TO EXTEND CRACK. THEREFORE DRILL A SMALL
HOLE AT END OF CRACK POINT (AI TO DISTRIBUTE STRAIN OVER WIDER AREA.
(AL
EACH CRACK OCCURRING AT ANY HOLE OR TEAR IS DRILLED IN SAME MANNER.
FIGURE 9.1.-Stop-drilling cracks.
bind or crack at the edge of the holes. The use of slotted holes is also recommended.
378. REPAIR OF PLASTICS. Replace extensively SUMAC E PATCH damaged transparent plastic rather than repair whenever possible since even a carefully DELLE patched part is not the equal of a new section either optically or structurally. At the first sign of crack development, drill a shall hole at the extreme ends of the cracks as shown in SURFACE PATCH FOR CRAC figure 9.1. This serves to localize the cracks and to prevent further splitting by distributing the strain over a large area. If the cracks are small, stopping them with drilled holes will usually suffice until replacement or more permanent repair can be made. The following repairs are permissible; however, they are not to be located in the pilot's line of vision during landing or normal fight. SURFACE PATCH FOR IRREGULAR R SHAPED DAMAGE
a. Surface Patch. If a surface patch is to be installed, trim away the damaged area and round all corners. Cut a piece of plastic of sufficient size to cover the damaged area and extend at least 8/4 Inch on each side of the crack or hole. Bevel the edges as shown in figure 9.2.
If the section to be repaired is curved, shape the patch to the same contour by heating it in SURFACE PATCH FOR ROUND HOLES an oil bath at a temperature of 248° to 802° F., or it may be heated on a hotplate until soft, FIGURE 9.2.-Surface patches Far 377 Chap 9
AC 43.13-1A Page 161 1972 Boiling water should not be used for heating.
Coat the patch evenly with plastic solvent adhesive and place immediately over the hole.
Maintain a uniform pressure of from 5 to 10 pounds per square inch on the patch for a minimum of 3 hours. Allow the patch to dry 24 to 36 hours before sanding or polishing is attempted.
b. Plug Potch. In using inserted patches to repair holes in plastic structures, trim the holes to a perfect circle or oval and bevel the edges slightly. Make the patch slightly thicker than the material being repaired and similarly bevel the edges. Install patches in accordance with figure 9.3. Heat the plug until soft and press into the hole without cement and allow to cool to make a perfect fit. Remove the plug, coat the edges with adhesive, and then reinsert in the hole. Maintain a firm light pressure until the
PATCHES PATCH SHOULD BE
THICKER cement has set, then sand or file the edges level with the surface; buff and polish.
379. CLEANING AND POLISHING TRANSPARENT PLASTIC. Plastics have many advantages over glass for aircraft use, but they lack the surface hardness of glass, and care must be exercised while servicing the aircraft to avoid scratching or otherwise damaging the surface.
a. Cleaning. Clean the plastic by washing with plenty of water and mild soap, using a clean, soft, grit-free cloth, sponge, or bare hands. Do not use gasoline, alcohol, benzene, acetone, carbon tetracholoride, fire extinguisher or deicing fluids, lacquer thinners, or window cleaning sprays because they will soften the plastic and cause crazing.
b. Plastics should not be rubbed with a dry cloth since this is likely to cause scratches, and also build up an electrostatic charge which attracts dust particles to the surface. If after removing dirt and grease no great amount of scratching is visible, finish the plastic with a good grade of commercial wax. Apply the wax in a thin even coat and bring to a high polish by rubbing lightly with a soft cloth.
c. Polishing. Do not attempt hand polishing PATCH AND HOLE PATCH TAPERED or buffing until the surface is clean. A soft, SHOULD BE TRIMMED ON SHARPER open-type cotton or flannel buffing wheel is sug- WITH TAPERED EDGES. MATERIAL. ANGLE THAN gested. Minor scratches may be removed by vigorously rubbing the affected area by hand, using a soft clean cloth dampened with a mix- HEAT EDGES OF DURING CEMENT- ture of turpentine and chalk, or by applying PATCH UNTIL SOFT AND FORCE IT IN NEED BE APPLIED ONLY ON TOP ING - PRESSURE the cleaner and polish with a soft, dry cloth. automobile cleanser with a damp cloth. Remove HOLE. HOLD SURFACE. TAPER Acrylic and cellulose acetate plastics are ther- IT IN PLACE ASSURES EQUAL moplastic. friction created by buffing or pol- UNTIL COOL AND HARD TO ASSURE PER- PRESSURE ON ALL SIDES, cient heat to soften the surface. This will ishing too long in one spot can generate suffi- FECT FIT. produce visual distortion and is to be guarded THEN REMOVE against.
PATCH FOR CEMENTING BATH. AFTER CEMENT HAS HARDENED - SAND OR 380. EMERGENCY EXITS. The following material is intended as a guide for the inspection and FILE EDGES LEVEL maintenance of aircraft emergency exit provi- WITH SURFACE. sions. Schedule inspections to coincide with all 100-hour/annual, progressive inspections or the maintenance procedures that have been ap- FIGURE 9.3.--Plug patch repair. proved by the Administrator. Before begin- Chap 9 Par 378
ning inspection or maintenance activities of any type, consult the appropriate manufacturer's service manual for information specifying the type of exit release mechanism used.
o. Inspection. Examine the emergency exits and all associated hardware closely for deformation, excessive wear, security of attachment, lubrication, and cleanness.
(1) Doors.
(a) Inspect the door structure and skin for wrinkles, cracks, alignment with the fuselage, deep scratches, dents, loose rivets, corrosion, or any other indication of structural irregularity.
(b) Examine rubber seals for cuts, tears, excessive wear, proper contact with the entire door frame, and general deterioration.
(c) Inspect bearings, hinges, hinge fairings, latches, springs, pins, rods, handles, and related parts for wear and general condition.
(d) Examine the door jamb, frame, and supporting structure for cracks, loose fasteners, condition of stops, and corrosion or
(e) Check the door for ease of operation and freedom of movement through its full range of travel.
(f) If a door warning light is provided, test it for proper operation and adjustment.
(g) Check the door locking mechanism for positive fit and at least the minimum lock pin engagement as specified in the applicable aircraft manual.
(2) Passenger Escape Hatches.
(a) Remove the escape hatch. Check for ease of removal and correct functioning of the release mechanism through all angles of pull likely to be encountered during emergency conditions.
CAUTION If applicable, position one man outside the aircraft to catch the hatch, thereby preventing it from falling and damaging the wing and/or hatch.
(b) Examine the escape hatch structure for cracka, dents, deep scratches, alignment, loose rivets and/or bolts, corrosion, or any other indication of structural irregularity.
(c) Inspect the rubber seals for excessive Par 380 AC 43.13-1A 1972 wear, deterioration, cuts, tears, and proper contact with the fuselage.
(d) Check the operating mechanisms for wear, cracks, and general condition; springs for proper tension, alignment, and security.
(e) If applicable, inspect external release mechanisms for wear, cracks, and proper operation. Check for presence and legibility of external placards and exit location markings.
(f) Examine the escape hatch opening jamb, frame, stops, and skin for cracks and other evidence of damage or failure.
(g) If an emergency escape rope is provided, check it for accessibility, attachment, freedom of operation, rot, broken strands, and general condition. Inspect the storage container or tube for sharp edges or moisture.
(3) Crew Compartment Sliding Windows.
(a) Inspect the window frame for cracks, dents, questionable scratches, loose rivets, corrosion, or any other indication of structural irregularity.
(b) Examine the extrusion seal for wear, general deterioration, and proper contact with the fuselage canopy.
(c) Check the window teleflex mechanism for loose bearings, wear, corrosion, and proper operation.
(d) Inspect the windows for cracks, scratches, nicks, crazing, fogging or moisture between panes, delaminations, hot spots or discoloration.
NOTE: Fogging or delaminations of windows other than windshields are generally not cause for replacement unless visibility is impaired. It is suggested the manufacturer be consulted on any question concerning win-
(1) Lubrication. Lubricate all moving parts of the exit latching mechanisms. The following practices will generally apply when specifc procedures are not available.
(a) Piano hinges and operating mechanism pivot points-oil lightly and wipe off excess. Use only oil that is compatible with the type of seal used on that specific aircraft. Do not allow the oil to contact fabrics or finished surfaces.
(b) Latch bolts and sliding surfaces- Chap o
AC 43.13-1A 1972 apply a light film from a graphite stick or latch lubricant (door ease).
(2) Seal Replacement. Information pertaining to special handling procedures for seals, gaskets, lubricants (dry or liquid), age limitations (shelf life), and types of adhesives may be found in the manufacturer's maintenance and overhaul manuals. Check the thickness of the seal or gasket for uniformity to prevent warping of the component, i.e., hatch or door. Exercise care when using adhesives to cement seals to the hatch frame or exit door as spillage or excessive amounts could cause the exit to bind.
NorE: Replace seals and gaskets with materials recommended by the manufacturer. Many times these materials have been changed due to service experience, therefore a check of manufacturers' service information should be made to ascertain that any replacement parts, materials, etc., are those currently recommended.
(3) Hatch/Window Replacement. Check replacement hatches or windows for proper size and fit to preclude opening problems. Improper loading of the aircraft or an accident may cause binding of the hatch/window if inadequate clearance exists.
(4) Emergency Exit Service Difficulties. Emergency exits that fail to open unless extreme force is exerted are usually caused by one of the following:
(a) Paint or primers on the mating surfaces of the exit which are not allowed to dry completely. As a result, the surfaces will stick to each other.
(b) Latches that bind or fail to work unless pulled straight out.
(c) Failure to lubricate mating or rubbing surfaces.
(d) Failure to operate exits after final assembly. The exits may perform satisfactorily before the airplane is painted, but the finishing process results in the application of solvents, cleaners, primers, and paint finishes that may tend to make the exit inoperable. Check the exit for ease of release after painting and finishing of an aircraft.
c. Operational Considerations.
Chap 9 Page 163
(1) Placards. Check to assure that all required placards and markings are installed (FAR 23.1557 (d) or 25.811). Make certain that curtains, drapes, clothes racks, etc. do not cover the placard or the exit operating handle.
When the normal exit identification signs are obstructed by compartmentation, galleys or other similar furnishings, use signs which contain the word "EXIT" and appropriate arrows to direct the attention of occupants to the exit locations.
(2) Precautions. Following any cabin interior modifications or configuration changes, check the accessability and operation of emergency exits by actual operation of the exit.
(a) Certain types of escape hatches have release handles which will not reinstall the lock pins into their locked position. If this type of release handle is pulled to any degree, either intentionally or inadvertently, it is necessary to ascertain that the locking pins are in position and safetied.
(b) Safety wire used to secure aircraft egress provisions should be of the type recommended by the manufacturer. Do not use stainless steel or other types of stiff wire. Acceptable substitutes would be either .011 copper or .020 aluminum soft safety wire.
(c) Some aircraft have inflatable door seals which assure a positive sealing capability during pressurization. Check these systems for proper operation in accordance with the manufacturer's maintenance instructions.
(d) Ascertain that seatbacks, tables, cabinets and other furnishings cannot interfere with the accessibility and opening of any exit either from inside or outside of the aircraft.
(3) Power Assist Devices. Some aircraft are presently equipped with powered systems to assist in door opening. It is imperative that the manufacturers' service instructions and manuals be reviewed before any maintenance is performed on such systems. These devices are usually hydraulically powered and, during an emergency condition, utilize a high-pressure bottle system as an alternate source (pneu- Par 380
Page 164 AC 43.13~1A 1972 matic or CO,). Future designs will quite possibly involve various combinations of hydraulic, electrical, or pneumatic units. Strict attention to all servicing procedures will be essential to assure proper functioning of the power-assist device when needed in an emergency.
381.-391. RESERVED.
Par 380 Chap 9