Par 10-20 Page 10-16
10-20. LOADING CONDITIONS AND/OR PLACARDS. If the following items have not been covered in the W&B extreme condition checks and are not covered by suitable placards in the aircraft, additional computations are necessary. These computations should indicate the permissible distribution of fuel, passengers, and baggage that may be carried in the aircraft at any one time without exceeding either the maximum weight or CG range. The conditions to check are:
a. With full fuel, determine the number of passengers and baggage permissible.
b. With maximum passengers, determine the fuel and baggage permissible.
c. With maximum baggage, determine the fuel and the number and location of passengers.
d. Examples of the computations for the above items are given in Figures 10-12, 10-13, and 10-14 respectively. The above cases are mainly applicable to the lighter type personal aircraft. In the case of the larger type transport aircraft, a variety of loading conditions is possible and it is necessary to have a loading schedule.
FIGURE 10-12. LOADING CONDITIONS: DETERMINATION OF THE NUMBER OF
PASSENGERS AND BAGGAGE PERMISSIBLE WITH FULL FUEL
EXAMPLE OF THE DETERMINATION OF THE NUMBER OF PASSENGERS AND BAGGAGE
PERMISSIBLE WITH FULL FUEL Actual empty weight of the aircraft 1169# Empty weight center of gravity - 10.6" Maxımum weight- - 2100# Datum is leading edge of the wing Forward center of gravity limit -- 8.5" Rearward center of gravity limit- 21.9" Oil capacity, 9 qts.; show full capacity 17# at -49" Baggage, maximum 100# at +75.5" Two passengers in rear seat, 170# x 2 - 340# at +48" Pilot in most rearward seat equipped with controls (unless otherwise placarded) - 170# at +16" Full fuel, 40 gals. x 6# -- 240# at +22" Weight (#) x Arm (*) = Moment (*#) Aircraft empty + 1169 + 10.6 + 12391 Oil + 17 - 49 833 Full Fuel + 240 + 22 + 5280 Passengers 2 rear + 340* + 48 +16320 Pilot + 170 + 16 + 2720 Baggage + 100 + 75.5 + 7550 Total + 2036 (IW) + 43428 (IM) Divide the TM (total moment) by the TW (total weight) to obtain the loaded center of gravity.
TM = 43428 = + 21.3" TW 2036 The above computations show that with full fuel, 100 pounds of baggage and two passengers in the rear seat may be carried in this aircraft without exceeding either the maximum weight or the approved C. G. range.
This condition may be entered in the loading schedule as follows:
GALLONS OF FUEL NUMBER OF PASSENGERS POUNDS OF BAGGAGE Full 2 Rear 100 * Only two passengers are listed to prevent the maximum weight of 2100 Ibs. from being exceeded.
Par 10-20 Page 10-17
FIGURE 10-13. LOADING CONDITIONS: DETERMINATION OF THE FUEL AND
BAGGAGE PERMISSIBLE WITH MAXIMUM PASSENGERS
EXAMPLE OF THE DETERMINATION OF THE POUNDS OF FUEL AND BAGGAGE PERMISSIBLE
WITH MAXIMUM PASSENGERS Weight (#) X Arm (*) = Moment (*#) Aircraft empty + 1169 + 10.6 + 12391 Oil 17 - 49 833 Pilot + 170 + 16 + 2720 Passenger (1) front + 170 + 16 + 2720 Passenger (2) rear + 340 + 48 +16320 Fuel (39 gals.) + 234 + 22 + 5148 Baggage Total + 2100 + 38466 Divide the TM (total moment) by the TW (total weight) to obtain the loaded center of gravity.
TM = 38466 = + 18.6" TW 2100 The above computations show that with the maximum number of passengers, 39 gallons of fuel and zero pounds of baggage may be carried in this aircraft without exceeding either the maximum weight or the approved C. G. range.
This condition may be entered in the loading schedule as follows:
GALLONS OF FUEL NUMBER OF PASSENGERS POUNDS OF BAGGAGE *Full *2 Rear * 100 39 1(F) 2(R) None * Conditions as entered from Figure 10-12 (F) Front seat (R) Rear seat Par 10-20 Page 10-18
FIGURE 10-14. LOADING CONDITIONS: DETERMINATION OF THE FUEL AND
THE NUMBER AND LOCATION OF PASSENGERS PERMISSIBLE WITH
MAXIMUM BAGGAGE
EXAMPLE OF THE DETERMINATION OF THE FUEL AND THE NUMBER AND LOCATION OF
PASSENGERS PERMISSIBLE WITH MAXIMUM BAGGAGE Weight (#) x Arm (*) = Moment (*#) Aircraft empty + 1169 + 10.6 + 12391 Oil 17 - 49 833 Pilot + 170 + 16 + 2720 Passenger (1) rear + 170 + 48 + 8160 Passenger (1) front + 170 + 16 + 2720 Fuel (40 gals.) + 240 + 22 + 5280 Baggage + 100 + 75.5 + 7550 Total + 2036 + 37988 Divide the TM (total moment) by the TW (total weight) to obtain the loaded center of gravity.
TM = 37988 - = + 18.7 TW 20366 The above computations show that with maximun baggage, full fuel and 2 passengers (1 in the front seat and 1 in the rear seat) may be carried in this aircraft without exceeding either the maximum weight or the approved C. G. range.
This condition may be entered in the loading schedule as follows:
GALLONS OF FUEL NUMBER OF PASSENGERS POUNDS OF BAGGAGE *Full *2 Rear * 100 ** 39 *1(F) 2(R) **None Full 1(F) 1(R) Full * Conditions as entered from Figure 10-12 ** Conditions as entered from Figure 10-13 (F) Front seat (R) Rear seat
10-21. EQUIPMENT LIST. A list of the equipment included in the certificated empty weight may be found in either the approved AFM or the W&B report. Enter into the W&B report all required, optional, and special equipment installed in the aircraft at time of weighing and/or subsequent equipment changes.
a. Required equipment items are listed in the pertinent Aircraft Specifications.
b. Optional equipment items are listed in the pertinent Aircraft Specifications and may be installed in the aircraft at the option of the owner.
Par 10-20 Page 10-19
c. Special equipment is any item not corresponding exactly to the descriptive information in the Aircraft Specifications. This includes items such as emergency locator transmitter (ELT), tail or logo lights, instruments, ashtrays, radios, navigation lights, and carpets.
d. Required and optional equipment may be shown on the equipment list with reference to the pertinent item number listed in the applicable specifications only when they are identical to that number item with reference to description, weight, and arm given in the specifications.
Show all special equipment items with reference to the item by name, make, model, weight, and arm. When the arm for such an item is not available, determine by actual measurement.
10-22. EQUIPMENT CHANGE. The person making an equipment change is obligated to make an entry on the equipment list indicating items added, removed, or relocated with the date accomplished, and identify himself by name and certificate number in the aircraft records.
Examples of items so affected are the installation of extra fuel tanks, seats, and baggage compartments.
a. Figure 10-15 illustrates the effect on balance when equipment items are added within the acceptable CG limits and fore and aft of the established CG limits.
FIGURE 10-15. EFFECTS OF THE ADDITION OF EQUIPMENT ITEMS ON
BALANCE
WEIGHTS FORWARD C.G. LIMIT - REARWARD C.G. LIMIT Weights added anywhere between the C.G. limits will not upset the balance of the aircrait.
-WEIGHT FORWARD C.G. LIMIT- -REARWARD C.G. LIMIT Any weights added ahead of the forward C.G. limit would tend to upset the balance around the forward balance limit.
WEIGHT FORWARD C.G. LIMIT -REARWARD C.G. LIMIT Any weights added aft of the rearward C.G. limit would tend to upset the balance around the rearward balance limit.
Par 10-21 Page 10-20
b. Moment computations for typical equipment changes are given in Figure 10-16 and are also included in the sample W&B sheet in Figure 10-18.
10-23. SAMPLE W&B REPORT. Suggested methods of tabulating the various data and computations for determining the CG, both in the empty weight condition and the fully loaded condition, are given in Figures 10-17 and 10-18, respectively, and represent a suggested means of recording this information. The data presented in Figure 10-17 have previously been computed in Figures 10-10 and 10-11 for the extreme load conditions and Figure 10-16 for equipment change, and represents suggested means of recording this information.
FIGURE 10-16. EXAMPLE OF MOMENT AND WEIGHT CHANGES RESULTING
FROM EQUIPMENT CHANGES Forward Rearward Moments (counterclockwise) + Moments (clockwise) Wheel pants added (+6# at -1") Battery added (+29# at +13") Battery removed -24# at -29") Landing light removed (-1# at +4") DATUM- Weight (#) × Arm (") = Moment ("#) ADDED Item 204 wheel pants + 6 - 1 - 6 Item 302b Battery + 29 + 13 +377
REMOVED Item 302a Battery - 24 -29 +696 Item 303 Landing light - 1 + 4 4 This condition is shown properly entered on a sample weight and balance report on Figure 10-18 under Equipment Change.
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FIGURE 10-17. SAMPLE WEIGHT AND BALANCE REPORT TO DETERMINE
EMPTY WEIGHT CENTER OF GRAVITY MAKE MA-700 MODEL A SERIAL # 0000 REGISTRATION # N1234 DATOM IS_ leading edge of wing
COMPUTE AS FOLLOWS IF AIRCRAFT WEIGHED
1. Leveling means: level top longeron between front and rear seats.
2. Main wheel weighing point is located - "FORWARD) (+ 3" AFT) of datum.
3. Actual measured distance from the main weight point centerline to the tail (or nose) point centerline 222 "
4. Oil over and above "ZERO" tank reading = (a. - Gals.) (b.- Lbs.) (c. - In.)
ACTUAL EMPTY WEIGHT Weight Point Scale Reading Tare = Net Weight
5. Right 564 564
6. Left 565 565
7. Tail 67 27 40
8. Nose
9. Total Net Weight 1169
CENTER OF GRAVITY AS WEIGHED
10. C.G. relative to main wheel weighing point:
(a) Tail wheel airc. (Item 3, 222), x (Item 7, 40 ) = C.G.
(Item 9, 1169)
(b) Nose wheel airc. (Item 3 ---) x (Item 8 ---- ) = C.G.
(Item 9 --- )
11. C.G. relative to datum:
(a) Tail wheel airc. (Item 10a, + 7.6) added to (Item 2, + 3) +10.6" = C.G.
(b) Nose wheel airc. (Item 10b. added to (Item 2, ) = = C.G.
COMPUTE IF AIRCRAFT WEIGHED WITH OIL (Item 4) Weight Arm Moment Aircraft (9) (11) Less Oil (4b) (4c) Empty Totals (a) (b)
(b) -- -= (c) = Empty weight C.G.
12. (a)
REPAIR AGENCY DATE Name Number Par 10-23 Page 10-22
FIGURE 10-18. SAMPLE WEIGHT AND BALANCE REPORT INCLUDING AN
EQUIPMENT CHANGE FOR AIRCRAFT FULLY LOADED
EQUIPMENT LIST *Required or Optional Item Numbers as Shown in Aircraft Specification 105 106 201 202 302(a) 303 401(a) 402 Special Equipment Item Make Model Weight Arm 3 Flares 1-1/2 Min XYZ 03 25# 105" Enter above those items included in the empty weight.
WEIGHT AND BALANCE EXTREME CONDITIONS Approved fid limit 8.5" Approved max. weight 2100# Approved aft limit 21.9" Item FORWARD CHECK REARWARD CHECK Weight Arm = Airo. Empty + 12391 + 1169 (9 or 12a) (11 or 12c) (9 or 12a) (11 or 12c) Oil + 17 - 49 - 833 Pilot + 170 + 16 + 2720 Fuel + 83 + 240 + 22 + 5280 Passenger (s + 340 + 48 + 16320 Baggage + 100 + 75.5 + 7550 TOTAL + 1439 = TW + 16104 = TM + 2036 = TW +43428=IM IM = 16104 = +11.2" = IM = 43428 = +21.3" = TW 1439 TW 2036 Most Forward C.G. location Most Rearward C.G. location
LOADING SCHEDULE Gallons Number of Pounds of of Fuel Passengers Baggage 40 2(R) 100 The above includes pilot and capacity oil
EQUIPMENT CHANGE Computing New C.G.
Item, Make, and Model* Weight Arm Moment Airc. Empty + 1169 + 10.6 + 12391 (9 or 12a) (11 or 12c) 204 added + 6 - 1 - 6 302(b) added + 29 + 13 + 377 302(a) removed - 24 + 29 + 696 303 removed - 1 + 4 - 4 NET TOTALS - 1179 = NW + 13454 = NM NM = 13454= +11.4" = New C.G.
NW 1179 *ITEM NUMBERS WHEN LISTED IN PERTINENT AIRCRAFT SPECIFICATION MAY BE USED IN LIEU OF "ITEM, MAKE, AND MODEL".
PREPARED BY DATE_ Par 10-23 Page 10-23
10-24. INSTALLATION OF BALLAST. Ballast is sometimes permanently installed for CG balance purposes as a result of installation or removal of equipment items and is not used to correct a nose-up or nose-down tendency of an aircraft. It is usually located as far aft or as far forward as possible in order to bring the CG position within acceptable limits with a minimum of weight increase. Permanent ballast is often lead plate wrapped around and bolted to the fuselage primary structure (e.g., tail-post, longerons, or bulkhead members). Permanent ballast invariably constitutes a concentrated load; therefore, the strength of the local structure and the attachment of the ballast thereto should be investigated for the design loading conditions pertinent to that particular aircraft. Placard permanent ballast with "Permanent ballast - do not remove." It is not desirable to install permanent ballast by pouring melted lead into the tail-post or longerons due to difficulties that may be encountered in subsequent welding repair operations. It should be noted that the installation of permanent ballast results in an increase of aircraft empty weight. See Figure 10-19 for ballast computation. The local strength of the compartment in which the ballast is carried and the effect of the ballast on aircraft W&B should be investigated when disposable ballast is carried.
FIGURE 10-19. PERMANENT BALLAST COMPUTATION FORMULA Desired C.G. location Actual C.G. location Location of ballast to D - Distance in inches desired to move C.G. of airplane. be added W - Weight of airplane as loaded.
X - Distance in inches from point where ballast is to be installed, to the desired location of the new C.G.
B - Weight of ballast required in pounds.
B = D × W Compute the new C.G. of the aircraft with ballast installed.
NOTE: If greater accuracy is desired, repeat the entire formula using the NEW aircraft weight and the NEW C.G. in the second operation.
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10-25. LOADING SCHEDULE. The loading schedule should be kept with the aircraft and form a part of the AFM. It includes instructions on the proper load distribution such as filling of fuel and oil tanks, passenger seating, restrictions of passenger movement, and distribution of cargo.
a. Other means of determining safe loading conditions such as the use of a graphical index and load adjuster are acceptable and may be used in lieu of the information in paragraph 10-20.
b. Compute a separate loading condition when the aircraft is to be loaded in other than the specified conditions shown in the loading schedule.
10-26.–10-34. [RESERVED.]
Par 11-1 Page 11-1 CHAPTER 11. AIRCRAFT ELECTRICAL SYSTEMS SECTION 1. INSPECTION AND CARE OF ELECTRICAL SYSTEMS
11-1. GENERAL. The term “electrical system” as used in this AC means those parts of the aircraft that generate, distribute, and use electrical energy, including their support and attachments. The satisfactory performance of an aircraft is dependent upon the continued reliability of the electrical system. Damaged wiring or equipment in an aircraft, regardless of how minor it may appear to be, cannot be tolerated. Reliability of the system is proportional to the amount of maintenance received and the knowledge of those who perform such maintenance.
It is, therefore, important that maintenance be accomplished using the best techniques and practices to minimize the possibility of failure. This chapter is not intended to supersede or replace any government specification or specific manufacturer’s instruction regarding electrical system inspection and repair.
11-2. INSPECTION AND OPERATION CHECKS. Inspect equipment, electrical assemblies, and wiring installations for damage, general condition, and proper functioning to ensure the continued satisfactory operation of the electrical system. Adjust, repair, overhaul, and test electrical equipment and systems in accordance with the recommendations and procedures in the aircraft and/or component manufacturer’s maintenance instructions. Replace components of the electrical system that are damaged or defective with identical parts, with aircraft manufacturer’s approved equipment, or its equivalent to the original in operating characteristics, mechanical strength, and environmental specifications. A list of suggested problems to look for and checks (see Appendix 1, Glossary, for a description of the check types) to be performed are:
a. Damaged, discolored, or overheated equipment, connections, wiring, and installations.
b. Excessive heat or discoloration at high current carrying connections.
c. Misalignment of electrically driven equipment.
d. Poor electrical bonding (broken, disconnected, or corroded bonding strap) and grounding, including evidence of corrosion.
e. Dirty equipment and connections.
f. Improper, broken, inadequately supported wiring and conduit, loose connections of terminals, and loose ferrules.
g. Poor mechanical or cold solder joints.
h. Condition of circuit breaker and fuses.
i. Insufficient clearance between exposed current carrying parts and ground or poor insulation of exposed terminals.
j. Broken or missing safety wire, broken bundle lacing, cotter pins, etc.
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k. Operational check of electrically operated equipment such as motors, inverters, generators, batteries, lights, protective devices, etc.
l. Ensure that ventilation and cooling air passages are clear and unobstructed.
m. Voltage check of electrical system with portable precision voltmeter.
n. Condition of electric lamps.
o. Missing safety shields on exposed high-voltage terminals (i.e., 115/200V alternating current (AC)).
11-3. FUNCTIONAL CHECK OF STAND-BY OR EMERGENCY EQUIPMENT. An aircraft should have functional tests performed at regular intervals as prescribed by the manufacturer. The inspections or functional check periods should be clearly stated in the aircraft maintenance manual, along with the overhaul intervals.
11-4. CLEANING AND PRESERVATION. Annual cleaning of electrical equipment to remove dust, dirt, and grime is recommended. Suitable solvents or fine abrasives that will not score the surface or remove the plating may be used to clean the terminals and mating surfaces if they are corroded or dirty. Only cleaning agents that do not leave any type of residue must be used. Components must be cleaned and preserved in accordance with the aircraft handbooks or manufacturer’s instructions. Avoid using emery cloth to polish commutators or slip rings because particles may cause shorting and burning. Be sure that protective finishes are not scored or damaged when cleaning. Ensure that metal-to-metal electrically bonded surfaces are treated at the interface with a suitable anti-corrosive conductive coating, and that the joint is sealed around the edges by restoring the original primer and paint finish. Connections that must withstand a highly corrosive environment may be encapsulated with an approved sealant in order to prevent corrosion.
CAUTION: Tu rn power off before cleaning.
11-5. BATTERY ELECTROLYTE CORROSION. Corrosion found on or near lead-acid batteries can be removed mechanically with a stiff bristle brush and then chemically neutralized with a 10-percent sodium bicarbonate and water solution. For Nickel Cadmium (NiCad) batteries, a 3-percent solution of acetic acid can be used to neutralize the electrolyte. After neutralizing, the battery should be washed with clean water and thoroughly dried.
11-6. ADJUSTMENT AND REPAIR. Accomplish adjustments to items of equipment such as regulators, alternators, generators, contactors, control devices, inverters, and relays at a location outside the aircraft, and on a test stand or test bench where all necessary instruments and test equipment are at hand. Follow the adjustment and repair procedures outlined by the equipment or aircraft manufacturer. Replacement or repair must be accomplished as a part of routine maintenance. Adjustment of a replacement voltage regulator is likely since there will always be a difference in impedance between the manufacturer’s test equipment and the aircraft’s electrical system.