Chapter 6 Weight and Balance
In a balance computation of an aircraft from which an item located aft of the datum was removed, use
(-)weight X (+)arm (-)moment
An aircraft with an empty weight of 1,500 pounds and an empty weight CG of +28.4 was altered as follows: 1. two 12-pound seats located at +68.5 were removed; 2. structural modifications weighing +28 pounds were made at +73; 3. a seat and safety belt weighing 30 pounds were installed at +70.5; and 4. radio equipment weighing 25 pounds was installed at +85
+30.30
An aircraft with an empty weight of 1,800 pounds and an empty weight CG of +31.5 was altered as follows: 1. two 15-pound passenger seats located at +72 were removed; 2. structural modifications increasing the weight 14 pounds were made at +76; 3. a seat and safety belt weighing 20 pounds were installed at +73.5; and 4. radio equipment weighing 30 pounds was installed at +30. What is the new empty weight CG?
+31.61
An aircraft with an empty weight of 2,100 pounds and an empty weight CG +32.5 was altered as follows: 1. two 18-pound passenger seats located at +73 were removed; 2 structural modifications were made at +77 increasing weight by 17 pounds; 3. a seat and safety belt weighing 25 pounds were installed at +74.5; and 4. radio equipment weighing 35 pounds was installed at +95 What is the new empty weight CG?
+33.68
If a 40-pound generator applies +1400 inch-pounds to a reference axis, the generator is located
+35 from the axis
Find the empty weight CG location for the following tricycle-gear aircraft. Each main wheel weighs 753 pounds, nosewheel weighs 22 pounds, distance between nosewheel and main wheels is 87.5 inches, nosewheel location +9.875 inches from datum, with 1 gallon of hydraulic fluid at -21.0 inches included in the weight scale
+96.11 inches
1
1
An aircraft had an empty weight of 2,886 pounds with a moment of 101,673.78 before several alterations were made, the alterations included: 1. Removing 2 passenger seats (15 pounds each) at +71; 2. Installing a cabinet (97 pounds) at +71; 3. Installing a seat and safety belt (20 pounds) at +71; 4. Installing radio equipment (30 pounds) at +94 The alterations caused the new empty weight CG to move
1.62 inches aft of the original empty weight CG
The following alternation was performed on an aircraft: A model B engine weighing 175 pounds was replaced by a model D engine weighing 185 pounds at a -62.00-inch station. The aircraft weight and balance records show the previous empty weight to be 998 pounds and an empty weight CG of 13.48 inches. What is the new empty weight CG?
12.73 inches
When an empty aircraft is weighed, the combined net weight at the main gears is 3,540 pounds with an arm of 195.5 inches. At the nose gear, the net weight is 2,322 pounds with an arm of 83.5 inches. The datum line is forward of the nose of the aircraft. What is the empty CG of the aircraft?
151.1
As weighed, the total empty weight of an aircraft is 5,862 pounds with a moment of 885,957. However, when the aircraft was weighed, 20 pounds of potable water were on board at +84, and 23 pounds of hydraulic fluid were in a tank located at +101. What is the empty weight CG of the aircraft?
151.365
1.basic empty weight
1The weight of a standard aircraft, operation equipment, usable fuel and full operating fluids ,including engine oil.
Two boxes which weigh 10 pounds and 5 pounds are placed in an airplane so that their distance aft from the CG are 4 feet and 2 feet respectively. How far forward of the CG should a third box, weighing 20 pounds, be placed so that the CG will not be changed?
2.5 feet
An aircraft as loaded weighs 4,954 pounds at a CG of +30.5 inches. The CG range is +32.0 inches to +42.1 inches. Find the minimum weight of the ballast necessary to bring the CG within the CG range. The ballast arm is +162 inches.
57.16 pounds
Datum is forward of the main gear center point 30.24 inches Actual distance between tail gear and main gear center points 360.26 inches Net weight at right main gear 9980 lb Net weight at left main gear 9770 lb Net weight at tail gear 1970 lb These items were in the aircraft when weighed: Lavatory water tank full (34 lb at +352) Hydraulic fluid (22 lb at -8) Removable ballast (146 lb at +380) What is the empty weight CG of the aircraft?
60.31 inches
reduction factor
A constant (usually 100 or 1000)by which moment is divided to obtain a moment index.
When determining the empty weight of an aircraft, certificated under current airworthiness standards (14 CFR Part 23), the oil contained in the supply tank is considered
A part of the empty weight
fulcrum
A point which a lever is supported, balanced ,or about which it turns.
platform scale
A type of moveable scale that can be placed under wheels of small aircraft
Forward Adverse Loading Check
A weight ad balance computation performed with the aircraft loaded in the most forward adverse loading condition to determine whether the aircraft ca be loaded outside of the CG range
Rearward Adverse Loading Check
A weight and balance computation performed with aircraft loaded in the most rearward adverse loading condition to determine whether it can be loaded outside the CG range
maximum gross weight check
A weight computation to determine whether it is possible to load the aircraft in a manner that can exceed the gross weight of an aircraft.
permanent ballast
A weight that has bee permanently installed in an aircraft to bring its center of gravity into allowable limits.
If the reference datum line is placed at the nose of an airplane rather than at the firewall or some other location aft of the nose...?
All measurements arms will be in positive numbers.
load cells
An electronic weighing component that contains strain gauges. It is placed between the aircraft jack pad and the jack to measure the weight of an aircraft.
When, or under what condition(s) are adverse loading checks conducted?
Anytime a repair or alteration causes EWCG to fall outside the CG range
When dealing with the weight and balance of an aircraft, the term "maximum weight" is interpreted to mean the maximum...?
Authorized weight of the aircraft and its contents.
The useful load of an aircraft consists of the...?
Crew, usable fuel, passengers, and cargo.
When accomplishing loading computations for a small aircraft, necessary information obtained from the weight and balance records would include
Current empty weight and empty weight CG
What type of measurement is used to designate the arm in weight and balance computation?
Distance.
The maximum weight of an aircraft is the...?
Empty weight plus useful load.
If it is necessary to weigh an aircraft with full fuel tanks, all fuel weight must be subtracted from the scale readings...?
Except unusable fuel.
When computing the maximum forward loaded CG of an aircraft, minimum weights, arms, and moments should be used for items of useful load that are located aft of the
Forward CG limit
All other things being equal, if an item of useful load located aft of an aircraft's CG is removed, the aircraft's CG change will be
Forward in proportion to the weight of the item and its location in the aircraft
An aircraft's LEMAC and TEMAC are defined in terms of distance
From the datum
To obtain useful weight data for purposes of determining the CG, it is necessary that an aircraft be weighed...?
In a level flight altitude.
Where do you look to determine the operating CG range when calculating a new aircraft weight and balance document?
It is found in the type certificate data sheet.
If the empty weight CG of an airplane lies within the empty weight CG limits,
It is not necessary to calculate CG extremes
Most modern aircraft are designed so that if all seats are occupied, full baggage weight is carried, and all fuel tanks are full, what will be the weight condition?
It will be in excess of maximum takeoff weight.
Which would have an effect on aircraft CG results when conducting a weigh and balance check?
Leaving the downlocks installed.
In the theory of weight and balance, what is the name of the distance from the fulcrum to an object?
Lever Arm.
The CG range in single-rotor helicopters is
More restricted than for airplanes
(1) Private aircraft are required by regulations to be weighed periodically. (2) Private aircraft are required to be weighed after making any alteration. Regarding the above statements...?
Neither No.1 nor No.2 is true.
In the process of weighing an airplane towards obtaining the CG, the arms from the weighing point always extend...?
Parallel to the centerline of the airplane.
When an aircraft is positioned for weighing on the scales located under each landing gear wheel, which of the following may cause erroneous scale readings?
Parking break set.
When making a rearward weight and balance check to determine that the CG will not exceed the rearward limit during extreme conditions, the items of useful load which should be computed at their minimum weights are those located forward of the
Rearward CG limit
Improper loading of a helicopter which results in exceeding either the fore or aft CG limits is hazardous due to the
Reduction or loss of effective cyclic pitch control
What tasks are completed prior to weighing an aircraft to determine its empty weight?
Remove All items except those on the aircraft equipment list; drain fuel and fill hydraulic reservoir.
The major source of weight change for most aircraft as they age is caused by...?
Repairs and alterations.
Which of the following can provide the empty weight of an aircraft if the aircraft's weight and balance records become lost, destroyed, or otherwise inaccurate?
Reweigh the aircraft.
Use of which of the following generally yields the highest degree of aircraft leveling accuracy?
Spirit level(s).
The empty weight of an airplane is determined by?
Subtracting the tare weight from the scales reading and adding the weight of each weighing point.
payload
That part of the useful load of an aircraft that is over and above the load necessary for the operation of the vehicle.The term used for passengers , baggage , and cargo.
When computing weight and balance, an airplane is considered to be in balance when?
The average moment arm of the loaded airplane falls within its CG range.
Mean Aerodynamic Chord (MAC)
The chord of an imaginary rectangular airfoil having the same aerodynamic characteristics as that of an actual wing.
CG range
The distance between forward and rearward center of gravity limits ,as specified on the Type Certificate Data Sheet for the aircraft.
What is meant by the term "residual fuel"?
The fuel remaining in the tanks, lines, and engine after draining.
arm
The horizontal distance in inches between the reference datum line and the center of gravity of an object. If the object is behind the datum, the arm is positive.
weighting points
The location on an aircraft where the scales are placed for weighing an aircraft.
Maximum weight
The maximum allowable weight for and aircraft under any condition
Maximum landing weight
The maximum authorized weight of an aircraft for landing
Maximum takeoff weight
The maximum design weight of any aircraft for takeoff.
The useful load of an aircraft is the difference between?
The maximum takeoff weight and basic empty weight.
Maximum Ramp Weight
The maximum weight approved for operation on the ground
moment index
The moment divided by a constant such as 200, 1,000 or 10,000.It is used to simplify weight and balance computations by eliminating large and unwieldy numbers
usable fuel
The portion of the total fuel load available to an aircraft in flight
Moment
The product of the weight of an object in pounds and in distance from the center of gravity of an object to the datum or fulcrum(the point about which a lever rotates)in inches. Moment is used in weight and balance computations and is expressed in pound-inches.
What determines whether the value of a moment is preceded by a plus (+) or minus (-) sign in aircraft weight and balance?
The result of a weight being added or removed and its location relative to the datum.
net weight
The scale weight weight subtracted from the weight of any item s not part of and aircraft such as chocks and blocks.
unusable fuel
The small amount of fuel in the tanks that cannot be safely used in flight or drained on the ground.
Tare Weight
The weight of all item such as blocks or chocks used to hold an airplane on the scale when it is weighted.
zero fuel
The weight of an aircraft to include all useful weight except fuel. limits the ratio of loads between the fuselage and wings
useful load
The weight of the occupants, baggage and usable fuel(Aircraft certified prior to FAR Part 23 include oil)2.The difference between ramp weight and the basic empty weight
Scale weight
The weight registered on the scaled used to weight an aircraft. The weight includes weight from all items on the scale including the aircraft and chocks.
What FAA-approved document gives the leveling means to be used when weighing an aircraft?
Type Certificate Data Sheet.
The amount of fuel used for computing empty weight and corresponding CG is
Unusable fuel
What should be clearly indicated on the aircraft weighing form?
Weighing points.
Which statement is true regarding helicopter weight and balance?
Weight and balance procedures for airplanes generally also apply to helicopters.
Temporary Ballast
Weight installed in an aircraft to brig it into GC range for specific flight condition
standard weights
Weights outlined by the FAA for use in calculation of weight and balance, including the weight of fuel , oil ,crew ,passengers and baggage.
If an aircraft CG is found to be at 24 percent of MAC, that 24 percent is an expression of the
distance from the LEMAC
The maximum weight as used in weight and balance control of a given aircraft can normally be found
in the Aircraft Specification or Type Certificate Data Sheet
Maximum zero fuel weight is the...?
maximum permissible weight of a loaded aircraft (passengers, crew, and cargo) without fuel.
Standard empty weight
the weight of an aircraft, including all permanently installed equipment ,hydraulic fluid ,unusable and full fuel.
