inch, and are frequently read to one-hundredth of an inch. Using this type of tape reduces the possibility y of errors associated with converting common fractions to decimals. These tapes are usually found in the weighing kit. CHALK LINE.—This is a string, covered with chalk, that is used to mark a straight chalked line on the hangar floor. It is used between the vertical projections of specified jig points. The string should be sturdy and hard finished. It usually accompanies the weighing kit. HYDROMETERS.—Use a hydrometer with a calibration range from 5.5 to 7.0 pounds per US gallon for determining the density of fuel. A transparent container for holding fuel samples, a pipette at least 12 inches long, or some other similar device for withdrawing samples from the tank, is necessary for use with the hydrometer. You must take care not to damage the glassware. To determine the density of a fuel sample, you should carefully place the hydrometer into the fluid within the transparent container. The hydrometer must not touch the container when you are reading the density, and you should take the reading at the lowest fuel point. NOTE: The hydrometer is used to determine fuel density for full fuel weighing. Since full fuel weighing is permitted only with specific NAVAIR (AIR-5222) approval, a hydrometer will not normally be apart of the weighing kit. Weighing Procedure A defined and orderly aircraft weighing procedure lessens the chance of omitting necessary dimensional or scale readings. The choice of alternative procedures depends upon the equipment at hand and on the circumstances under which the aircraft is to be weighed. Always refer to the particular aircraft’s Chart E loading data. The following procedures have been used successfully to accomplish proper aircraft weighing. Thoroughly clean the aircraft inside and out, removing dirt, grease, and moisture. Allow the aircraft sufficient time to dry before weighing. Assemble the required weighing equipment, including scales, hoisting equipment, jacks, cribbing, leveling bars, level, measuring tape, plumb bobs, and chalk line, Drain fuel in accordance with the aircraft’s Chart E or other applicable instructions. This draining is generally done in the aircraft’s normal ground attitude. Aircraft with internal foam in their fuel tanks pose special problems, since some fuel is always retained in the foam. In this case, unless specific instructions are in the aircraft’s Chart E, draining should be terminated when the fuel flow becomes discontinuous or starts to drip. Remove load items such as bombs, ammunition, cargo, crew members, and equipment not having a fixed position in the aircraft. They are not listed as a part of the basic weight on the Chart A, Basic Weight Checklist Record, DD Form 365A (DD Form 365-1), and should not be in the aircraft when weighed. Check all reservoirs and tanks for liquids such as drinking and washing water, hydraulic fluid, anti-icing fluid, cooling fluids, and liquid oxygen. Reservoirs and tanks should be empty or filled to normal capacity before weighing. Oil tanks are to be filled to normal capacity before weighing. Calculations on the Aircraft Weighing Record, DD Form 365-2, will resolve differences between the as-weighed condition and the basic-weight condition. All waste tanks must be empty. Move the aircraft to the area where it will be weighed. Do not set the aircraft brakes, for this may induce side loads and thrust loads on the scales, which, in turn, may give erroneous weighing results. The aircraft must be weighed in a closed hangar or building with no blowers or ventilating system blowing air upon the aircraft. Conduct a Chart A inventory of equipment actually installed in the aircraft. This inventory will be accomplished under the supervision of the qualified weight and balance technician (qualified by graduation from one of the NADEP weight and balance schools) responsible for weighing aircraft. A basic weight without the correct associate inventory is of no value. Correct the Chart C, Basic Weight and Balance Record, DD Form 365-3, based upon the Chart A inventory. Using such data as the current Chart C basic weight, the Chart A inventory, and the Chart E loading data, estimate an “as weighed” weight and moment. To the current basic weight, add the oil (if not part of current basic weight) and “items weighed but not part of the current basic weight,”  and subtract the “items in the basic weight but not in the aircraft.” When weighing an aircraft with platform scales such as the MEWS or stationary scales, assure that all scales are within their calibration date. If the scales are portable, set up the scales and level them. Attach the cables from the platform to the readout. Warm up electronic scales for a minimum of 20 minutes. Zero the scales. Level the aircraft by servicing. Most aircraft can be leveled in this reamer. See NAVAIR 01-1B-40 and 3-31