Weight & Balance for the Piper PA-28 Archer

The basic weight and C.G. location for a particular airplane are recorded in the Weight and Balance section of the Airplane Flight Manual. The current values should always be used. Whenever new equipment is added or any modification work is done, the mechanic responsible for the work is required to compute a new basic weight and basic C.G. position and to write these in the aircraft log book. The owner should make sure that it is done. A weight and balance calculation is necessary in determining how much fuel or baggage can be boarded so as to keep within allowable limits. Check calculations prior to adding fuel to insure against improper loading. The following pages are forms used in weighing an airplane in production and in computing basic weight, basic C.G. position, and useful load. Note that the useful load includes fuel, oil, baggage, cargo and passengers. Following this is the method for computing takeoff weight and C.G. ISSUED: MAY 14, 1973 REPORT: VB-547 PAGE 5-1 REVISED: MARCH 16, 1984 MODEL: PA-28-180 WEIGHT AND BALANCE DATA WEIGHING PROCEDURE CHEROKEE ARCHER At the time of licensing. Piper Aircraft Corporation provides each airplane with the licensed empty weight and center of gravity location. This data is on Page 5-7. The removal or addition of an excessive amount of equipment or excessive airplane modifications can affect the licensed empty weight and empty weight center of gravity. The following is a weighing procedure to determine this licensed empty weight and center of gravity location: 1. 2. PREPARATION a. b. C. d. e. f. Be certain that all items checked in the airplane equipment list are installed in the proper location in the airplane. Remove excessive dirt, grease, moisture, foreign items such as rags and tools from the airplane before weighing. Defuel airplane. Then open all fuel drains until all remaining fuel is drained. Operate engine on each tank until all undrainable fuel is used and engine stops. Drain all oil from the engine, by means of the oil drain, with the airplane in ground attitude. This will leave the undrainable oil still in the system. Engine oil temperature should be in the normal operating range before draining. Place pilot and copilot seats in fourth (4th) notch, aft of forward position. Put flaps in the fully retracted position and all control surfaces in the neutral position. Tow bar should be in the proper location and all entrance and baggage doors closed. Weigh the airplane inside a closed building to prevent errors in scale readings due to wind. LEVELING a. b. With airplane on scales, block main gear oleo pistons in the fully extended position. Level airplane (see diagram) deflating nose wheel tire, to center bubble on level. ISSUED: MAY 14, 1973 REVISED: MARCH 16, 1984 REPORT: VB-547 PAGE 5-3 MODEL: PA-28-180 CHEROKEE ARCHER A = B = 3. WEIGHING - AIRPLANE EMPTY WEIGHT a. With the airplane level and brakes released, record the weight shown on each scale. Deduct the tare, if any, from each reading. Scale Position and Symbol Nose Wheel (N) Right Main Wheel (R) Left Main Wheel (L) Airplane Empty Weight, as Weighed (T) 4. Scale Reading Net Tare Weight EMPTY WEIGHT CENTER OF GRAVITY a. The following geometry applies to the PA-28-180 airplane when airplane is level (See Item 2). C. G. Arm. Level Points (Fuselage) -78.4. C. G. N R+L REPORT: VB-547 PAGE 5-4 MODEL: PA-28-180 -Wing Leading Edge The datum is 78.4 inches ahead of the wing leading edge at the intersection of the straight and tapered section. ISSUED: MAY 14, 1973 CHEROKEE ARCHER b. C. d. Obtain measurement "A" by measuring from a plumb bob dropped from one wing leading edge, at the intersection of the straight and tapered section. horizontally and parallel to the airplane centerline, to the main wheel centerline. Obtain measurement "B" by measuring the distance from the main wheel centerline. horizontally and parallel to the airplane centerline, to each side of the nose wheel axle. Then average the measurements. The empty weight center of gravity (as weighed including optional equipment and undrainable oil) can be determined by the following formula: C.G. Arm = 78.4A B(N) - Τ C. G. Arm = 78.4 + ( )-( inches ( ) 5. LICENSED EMPTY WEIGHT AND EMPTY WEIGHT CENTER OF GRAVITY Weight Arm Moment Empty Weight (as weighed) Unusable Fuel (13-1/3 pints) +10.0 103.0 +1030 Licensed Empty Weight ISSUED: MAY 14, 1973 REVISED: JANUARY 20, 1975 REPORT: VB-547 PAGE 5-5 MODEL: PA-28-180 Airplane Serial Number_ Registration Number WEIGHT AND BALANCE DATA MODEL PA-28-180 CHEROKEE Date AIRPLANE EMPTY WEIGHT CHEROKEE ARCHER Item Weight X (Lbs) C. G. Arm (Inches Aft of Datum) = Moment (In-Lbs) *Empty Weight Actual Computed Unusable Fuel (13-1/3 pints) 10.0 103.0 1030 Standard Empty Weight Optional Equipment Licensed Empty Weight *Empty weight is defined as dry empty weight (including paint and hydraulic fluid) plus 1.8 lbs undrainable engine oil. AIRPLANE USEFUL LOAD (Gross Weight) - (Licensed Empty Weight) = Useful Load Normal Category: Utility Category: (2450 lbs) (1950 lbs) ) lbs) lbs) lbs lbs THIS LICENSED EMPTY WEIGHT. C.G. AND USEFUL LOAD FOR THE AIRPLANE AS LICENSED AT THE FACTORY. REFER TO APPROPRIATE AIRCRAFT RECORD WHEN ALTERATIONS HAVE BEEN MADE. ISSUED: MAY 14, 1973 REVISED: MARCH 16, 1984 REPORT: VB-547 PAGE 5-7 MODEL: PA-28-180 CHEROKEE ARCHER C. G. RANGE AND WEIGHT INSTRUCTIONS 1. Add the weight of all items to be loaded to the licensed empty weight. 2. Use the loading graph to determine the moment of all items to be carried in the airplane. Add the moment of all items to be loaded to the licensed empty weight moment. Divide the total moment by the total weight to determine the C.G. location. 3. 4. 5. By using the figures of Item 1 and Item 4. locate a point on the C.G. range and weight graph. If the point falls within the C.G. envelope, the loading meets the weight and balance requirements. SAMPLE LOADING PROBLEM (Normal Category) Weight (Lbs) Arm Aft Datum (Inches) Moment (In-Lbs) Licensed Empty Weight Oil (8 quarts) 15 27.5 413 Pilot and Front Passenger 340 80.5 27370 Passengers. Aft* (Rear Seat) 340 118.1 40154 Fuel (48 Gal. Maximum) 95.0 Baggage* 142.8 Total Loaded Airplane The center of gravity (C.G.) of this sample loading problem is at datum line. Locate this point ( inches aft of the ) on the C.G. range and weight graph. Since this point falls within the weight - C.G. envelope, this loading meets the weight and balance requirements. IT IS THE RESPONSIBILITY OF THE PILOT AND AIRCRAFT OWNER TO INSURE THAT THE AIRPLANE IS LOADED PROPERLY. *Utility Category Operation - No baggage or aft passengers allowed. REPORT: VB-547 PAGE 5-8 MODEL: PA-28-180 ISSUED: MAY 14, 1973 LOAD WEIGHT (POUNDS) 450 400 350 300 250 200 150 100 50 LOADING GRAPH Pilot and Front Passenger Fuel (6 lb/gal). Baggage 0 5 10 15 20 25 30 35 ISSUED: MAY 14, 1973 MOMENT/1000 (POUNDS - INCHES) CHEROKEE ARCHER Aft Passengers. 40 40 45 50 REPORT: VB-547 PAGE 5-9 MODEL: PA-28-180 CHEROKEE ARCHER 2800 2600 2400 2200 2000 C.G. RANGE AND WEIGHT UTILITY CATEGORY 1 1800 1600 1400 NORMAL CATEGORY 1200 82 84 86 88 90 92 94 96 REPORT: VB-547 PAGE 5-10 MODEL: PA-28-180 ISSUED: MAY 14, 1973