Question 88-1 : An aircraft is used for commercial air transport since the aircraft's initial entry into service 3 years ago several repairs and modifications have been executed these changes were accurately documented the operator uses individual aircraft masses does the aircraft need to be re weighed now ? [ Attainment AIM ]

Question 88-2 : Which section of the aircraft flight manual describes the centre of gravity limits of the aircraft ?

The aircraft limitations section.

An aircraft flight manual afm is a document published by the aircraft manufacturer containing detailed information for the operation of the aircraft such as the recommended aircraft operating technique for normal abnormal and emergency operation together with the aircraft performance that should be achieved when the aircraft is operated in accordance with these proceduresa typical afm may contain the following sections section 1 general section 2 limitations section 3 emergency procedures section 4 normal procedures section 5 performance section 6 weight and balance section 7 description and operation of the airplane and its systems section 8 airplane handling servicing and maintenance section 9 supplements section 10 operating tipsthe limitations section contains only those limitations required by regulation or that are necessary for the safe operation of the aircraft powerplant systems and equipment it includes operating limitations such as cg and load limits instrument markings color coding and basic placards

Question 88-3 : When must an operator ensure an aircraft is weighed ?

Every 4 years for individual aircraft.

A good rule for these questions is given by the wording 'individual' = 4 years'fleet' = 9 yearsthe other regulation often used is reweighing can be required whenever the cumulative change to the dom exceeds + 05% of the mlmfor example take the mrjt from cap 696 max landing mass is 54 900 kg x 05% = 2745 kgif any change or modification causes a weight gain or loss of more than 2745 kg then the aircraft must be revised this revised dom can be determined by actual weighing or calculationamc1 catpolmab100 b the mass and centre of gravity cg position of an aircraft should be revised whenever the cumulative changes to the dry operating mass exceed 05% of the maximum landing mass or for aeroplanes the cumulative change in cg position exceeds 05% of the mean aerodynamic chord

Question 88-4 : An aeroplane must be re weighed at certain intervals when an operator uses 'fleet masses' and provided that changes have been correctly documented this interval is… ?

9 years for each aeroplane.

If any changes are known properly documented and also do not change the dom by more than + 05% of the mlm then there is no need to reweighaccording to 'easa air ops catpolmab100 mass and balance loading' b the operator shall establish the mass and the cg of any aircraft by actual weighing prior to initial entry into service and thereafter at intervals of four years if individual aircraft masses are used or nine years if fleet masses are used the accumulated effects of modifications and repairs on the mass and balance shall be accounted for and properly documented aircraft shall be reweighed if the effect of modifications on the mass and balance is not accurately known

Question 88-5 : Which one of the following statements below best describes the centre of gravity cg of an aircraft ?

The cg is the point at which the total weight is assumed to be concentrated.

Starting with the cap 696 definition 'the centre of gravity cg is that point through which the force of gravity is said to act on a mass'the force of gravity acting on a mass gives us weight so to simply the cap definition the cg is the point through which the weight actsan aircraft is constructed of many parts all of which contribute to the weight the cg is the overall point at which they act along the longitudinal axislooking at the answers 'the cg is the point at which the sum of the balance arms is nil' > incorrect balance arms are just the distance from the datum not the effect'the cg is the point at which the total weight is assumed to be concentrated' > correct as described above'the cg is the point at which the sum of the values of the moments is not zero' > incorrect at the cg the sum of the weight moments is zero'the cg is the point at which the total weight is applied and acts in the longitudinal direction' > incorrect the weight acts vertically downwards with gravity

Question 88-6 : Which one of the following statements below best describes the centre of gravity cg of an aircraft ?

The cg is a theoretical point where all the mass is said to be concentrated.

Centre of gravity cg is the point along the longitudinal axis about which an aircraft would balance if it was possible to suspend it at that point it is the mass centre of the aircraft or the theoretical point at which the entire mass of the aircraft is assumed to be concentrated and acts vertically downward parallel to the gravity vector in a level flight or in a steady climb or descentthe cg is not necessarily a fixed point its location depends on the distribution of weight in the aircraft but must remain within certain forward and aft limits for reasons of stability control and structure considering both the flight and ground requirementsalso the limitations section contains only those limitations required by regulation or that are necessary for the safe operation of the aircraft powerplant systems and equipment it includes operating limitations such as cg and load limits instrument markings color coding and basic placards

Question 88-7 : During preparation for take off the flight crew received an acars load sheet message with the note prelim on the headerfive minutes later the ground staff provides a paper copy of the load sheet with the note final on the header the commander realizes that there are differences between the masses on ?

The commander shall use the paper copy because it is the final version of the load sheet.

Taking the question scenario step by step step 1 during preparation for take off the flight crew received an acars load sheet message with the note prelim on the header a preliminary load sheet is produced in advance of the flight's departure in order for the crew to plan fuel often before check in closes and is based on expected passenger numbers for example on an a380 this information is necessary to distribute the correct amount of fuel to the tail trim tank receiving a load sheet via acars printed in the cockpit is a normal situationstep 2 five minutes later the ground staff provides a paper copy of the load sheet with the note final on the header receiving a second load sheet by hand on paper is also a normal situation this load sheet has final noted as a header and supersedes the previous prelim version this is produced once check in has closed and has all the actual figures for the flight step 3 the commander realises that there are differences between the masses on the paper copy and the acars message this is normal as the final passenger and baggage figures at the close of check in will differ from the expected totalsstep 4 the commander shall use the paper copy because it is the final version of the load sheet this is the correct answer the final over rules the earlier prelim load sheet

Question 88-8 : According to the applicable operational requirements which one of the following statements is correct regarding the weighing and re weighing procedure of an aircraft ?

Weighing should be accomplished in an enclosed building.

Easa air ops catpolmab100 mass and balance loading b the operator shall establish the mass and the cg of any aircraft by actual weighing prior to initial entry into service and thereafter at intervals of four years if individual aircraft masses are used or nine years if fleet masses are used the accumulated effects of modifications and repairs on the mass and balance shall be accounted for and properly documented aircraft shall be reweighed if the effect of modifications on the mass and balance is not accurately known easa air ops amc1 catpolmab100 b mass and balance loading c when weighing an aircraft normal precautions should be taken consistent with good practices such as 1 checking for completeness of the aircraft and equipment 2 determining that fluids are properly accounted for 3 ensuring that the aircraft is clean and 4 ensuring that weighing is accomplished in an enclosed buildingthe operator must also account for and document the accumulated effects of modifications and repairs between weighings by either weighing the equipment added or removed or by using standard masses it must re weighed only if the accumulated effects of these modifications lead to a change of the dom by more than 05% of the mlm or the cg shifts by more than 05% of the mac

Question 88-9 : Due to variations in the actual passenger distribution cargo loading or fuel distribution in comparison with the data used during the pre flight preparation of the mass and balance documentation the operator 1 which isare 2 restrictive than the certified cg limits ?

1 defines operational cg limits 2 more.

The operator is responsible for producing mass and balance documentation before each flight specifying the load and distribution so that the aircraft commander can determine that the mass and balance limits are not exceededwhen determining the final cg position for flight there will inevitably be inaccuracies in the loadsheet in the actual mass of the item and its position on the aircraft fuel consumption fuel transfer passenger movement crew movement and configuration changes in flight need to be accounted foralso both the cg position and the safe envelope evolve throughout the flight indeed the weight of the aircraft evolves mainly as fuel is burned as for the cg its position is sensitive to various phenomena ranging from landing gear flaps and slats position to passengers or cabin crew movements from one end of the cabin to the otherto allow a margin of safety for these variations the certified cg limits are reduced to the operational limits ie the operational cg limits are more restrictive than the certified cg limits because error margins have been taken into account the operational cg limits are determined by the operator one for take off and another one for zero fuelalthough there were attempts at developing systems to measure the aircraft weight and cg position no robust solution has yet been found the best way to make sure that the cg remains within a safe envelope throughout the flight is to both define an operational envelope that includes safety margins and to perform a correct cg calculation

Question 88-10 : Where can information on the cg limits of an aircraft be found ?

Aircraft flight manual.

The aircraft flight manual afm is a document provided by the aircraft manufacturer that contains information and instructions on the operation of a specific aircraft it is a legally required document and must be carried on board the aircraft at all times it includes the following information description of the aircraft's systems and dimensionsoperating envelope normal and abnormal procedures aircraft limitations maximum weights cg limits recent changes to aircraft operating techniques performance datacalculation techniques

Question 88-11 : The basic empty mass bem and the basic empty mass centre of gravity cg position are noted in… ?

The weighing report.

The basic empty mass bem and the basic empty mass center of gravity cg position are typically noted on the aircraft weighing report this report is prepared after the aircraft has been weighed and it provides important information about the weight and balance of the aircraft the information from the weighing report is used to calculate the weight and balance for each flight and this information is typically recorded on the load and trim sheet so while the bem and cg position are not directly noted on the load and trim sheet they are derived from the information on the weighing report and used to complete the load and trim sheet

Question 88-12 : The mean aerodynamic chord published in the flight manual of an aeroplane starts at 520 mm and ends at 1700 mm from the datum line the centre of gravity of a loaded aeroplane is 30% macdetermine the associated distance of the cg position to the datum ?

874 mm.

For the swept wing aircraft it is more convenient for aerodynamic purposes to relate the cg position to the mean aerodynamic chord mac of a wing in this case the cg is expressed as a percentage of its position along the mac %mac from the leading edge lemac for this question 30% mac means that the cg is 30% along the mac length mac length = 1 700 mm 520 mm = 1 180 mm this corresponds to 1 180 mm x 030 = 354 mm aft from the lemacthe lemac is 520 mm aft from the datum thus the cg position is 520 mm + 354 mm = 874 mm aft of the datum

Question 88-13 : An aeroplane with one nose landing gear and two main landing gears is weighed on jacks based on the following readouts what is the aircraft bem and cg position nose jack positioned at 161 inches aft of datum reading 6848 kg each main wheel jack positioned at 757 inches aft of datum reading 11 873 kg ?

30 594 kg and 6236 in.

The nose gear wheel load is 6848 kg the main gear wheels load is 2 x 11 873 kg = 23 746 kg two wheels with a single wheel load of 11 873 kg total mass of aircraft = bem = 6848 kg + 23 746 kg = 30 594 kgmoment is the turning force created by the mass acting over a distance or arm and is calculated by multiplying the arm by the mass or weight moment = arm x mass or weightmoments aft of the datum are by convention positive and moments forward of the datum are negativethe centre of gravity cg can be found by adding all the moments and then dividing the total moment by the total mass or weight cg =total moment total weightcg = total moment total weight = 23 746 kg x 757 in + 6848 kg x 161 in 30 594 kg = 19 078 250 kg in 30 594 kg = 6236 in aft of datum

Question 88-14 : The cg is at 25% mac where is it located ?

Behind the leading edge of the mean aerodynamic chord lemac .

Generally the centre of gravity cg is expressed as a distance l relative to a datum or reference point but cg is usually expressed in swept wing aircraft as a distance relative to the mean aerodyanmic chord mac of a wing the mac mean aerodynamic chord represents the chord of an imaginary airfoil that has the same aerodynamic characteristics as the actual wing to be more specific the cg is expressed as a percentage of its position along the mac %mac from the leading edge le also called lemaclemac this is the leading edge of the mean aerodynamic chord it represents 0% of the mactemac this is the rear edge of the mac and is considered 100% of the macif the cg is at a distance l from the datum then the correct formula to calculate the cg position as a percentage of the mac is l lemac mac x 100the cg is at 25% mac which means it is 25% of the chord length back from the lemac this means that the cg is located behind the leading edge of the mean aerodynamic chord lemac note the option 'forward of the trailing edge of the mean aerodynamic chord temac ' is technically true but it describes the position in relation to the temac which is normally given as a distance and not as a percentage of mac

Question 88-15 : The formula l lemac mac x100 is used to calculate the cg position as a percentage of the mac if lemac is the distance from the datum to the leading edge and mac is the length of the mean aerodynamic chord l is the distance between the cg and the ?

Datum.

generally the centre of gravity cg is expressed as a distance l relative to a datum or reference point but cg is usually expressed in swept wing aircraft as a distance relative to the mean aerodyanmic chord mac of a wing the mac mean aerodynamic chord represents the chord of an imaginary airfoil that has the same aerodynamic characteristics as the actual wing to be more specific the cg is expressed as a percentage of its position along the mac %mac from the leading edge le also called lemac lemac this is the leading edge of the mean aerodynamic chord it represents 0% of the mac temac this is the rear edge of the mac and is considered 100% of the macif the cg is at a distance l from the datum then the correct formula to calculate the cg position as a percentage of the mac is l lemac mac x 100

Question 88-16 : In the formula to calculate the cg position as a percentage of the mean aerodynamic chord l lemac mac x 100 what does the l represent ?

Cg distance from datum.

The formula to calculate the cg position as a percentage of the mean aerodynamic chord is l lemac mac x 100wheremac the length of the mean aerodynamic chord lemac the distance of the mean aerodynamic chord leading edge from the datum and l = cg distance from datum temac the distance of the mean aerodynamic chord trailing edge from the datum generally the centre of gravity cg is expressed as a distance l relative to a datum or reference point but cg is usually expressed in swept wing aircraft as a distance relative to the mean aerodynamic chord mac of a wing to be more specific the cg is expressed as a percentage of its position along the mac %mac from the leading edge le also called lemacif the cg is at a distance l from the datum then the correct formula to calculate the cg position as a percentage of the mac is l lemac mac x 100

Question 88-17 : The mass of an aircraft is 1950 kgif 450 kg is added to a cargo hold 175 metres from the loaded centre of gravity cg the loaded cg will move ?

33 cm.

Change of cg = mass added x distance from hold to cg new total masschange of cg = 450 x 175 1950 + 450 change of cg = 03281 m 33 cm

Question 88-18 : If nose wheel moves aft during gear retraction how will this movement affect the location of the centre of gravity cg on the aircraft ?

It will cause the cg to move aft.

If the nose wheel moves aft the cg moves aftthe cg is that point through which the force of gravity is said to act on a mass and always acts parallel to the gravity vector

Question 88-19 : Where is the centre of gravity of the aeroplane in the diagram 185 ?

2657 cm forward of datum.

Total moments 1 x 1750 + 25 x 8130 = 22075 nsum of total moments sum of total weight = cg position22075 n 9880 kg = 2234325 22343 = 02657 m 2657 cm

Question 88-20 : Given total mass 2900 kgcg location station 115aft cg limit station 116the maximum mass that can be added at station 130 is ?

207 kg.

Mass added old total mass = change of cg distance from hold to new cgmass added = change of cg distance from hold to new cg x old total massmass added = 116 115 130 116 x 2900mass added = 207 kg

Question 88-21 : Given total mass 7500 kgcentre of gravity cg location station 805aft cg limit station 795how much cargo must be shifted from the aft cargo compartment at station 150 to the forward cargo compartment at station 30 in order to move the cg location to the aft limit ?

625 kg.

Mass moved total mass = change of cg distance movedmass moved = change of cg x total mass distance movedmass moved = 1 x 7500 kg 150 30 mass moved = 7500 120mass moved = 625 kgyou need to move cg from station 805 to station 795

Question 88-22 : A jet aeroplane with the geometrical characteristics shown in the appendix has a take off weight w of 460 000 n and a centre of gravity point g on annex located at 1540 m from the zero reference pointat the last moment the station manager has 12 000 n of freight added in the forward compartment at ?

275 %.

Mass x arm = moment460000 n x 154 m = 7084000 nm12000 n of last minute cargo is added to a hold 10 m from the datum 12000 n x 10 m = 120000 nmnew mass is 472000 nnew moment is 7204000 nmcg position is now 7204000 472000 = 1526 m from the zero reference pointin percentage of mean aerodynamic chord it is lemac leading edge mean aerodynamic chord is at 14 m therefore cg is at 126m from lemac 1526m 14m 126 46 x 100 = 275% mac

Question 88-23 : The total mass of an aeroplane is 9000 kg the centre of gravity cg position is at 20 m from the datum line the aft limit for cg is at 21 m from the datum linewhat mass of cargo must be shifted from the front cargo hold at 08 m from the datum to the aft hold at 38 m to move the cg to the aft limit ?

300 kg.

21 2 x 9000 = mass to moved x 38 08 900 = mass to moved x 3mass to moved = 900 3 = 300 kg

Question 88-24 : Assume aircraft actual mass 4750 kgcentre of gravity at station 1158what will be the new position of the centre of gravity if 100 kg is moved from the station 30 to station 120 ?

Station 11769.

Mass moved total mass = change of cg distance movedmass moved x distance moved total mass = change of cg100 x 90 4750 = 189new cg location 1158 + 189 = 11769

Question 88-25 : Given aircraft mass 36000 kgcentre of gravity cg is located at station 17 mwhat is the effect on cg location if you move 20 passengers total mass 1600 kg from station 16 to station 23 ?

It moves aft by 031 m.

We move passangers aft thus the cg will move aftmass moved total mass = change of cg distance movedchange of cg = mass moved x distance moved total masschange of cg = 1600 x 7 36000 = 031 m

Question 88-26 : Given the following information calculate the loaded centre of gravity cg 197 ?

5653 cm aft datum.

Img133centre of gravity = 1 369 350 24224 = 56528 aft of datum

Question 88-27 : Given are the following information at take offgiven that the flight time is 2 hours and the estimated fuel flow will be 1050 litres per hour and the average oil consumption will be 225 litres per hourthe specific density of fuel is 079 and the specific density of oil is 096calculate the landing ?

6128 cm aft of datum.

Fuel = 2100 l x 079 = 1659 kghuile = 45 l x 096 = 432 kg 134centre of gravity at landing = 13824492 2256068 = 6128 aft of datum

Question 88-28 : Given that the total mass of an aircraft is 112000 kg with a centre of gravity position at 2262 m aft of the datumthe centre of gravity limits are between 18 m and 22 mhow much mass must be removed from the rear hold 30 m aft of the datum to move the centre of gravity to the middle of the limits ?

29344 kg.

Mass moved total mass = change of cg distance movedmass moved = change of cg x total mass distance movedmass moved = 2262 20 x 112000 kg 30 20 mass moved = 293440 kg 10mass moved = 29344 kgnotice the middle of the limits is at 20m cg limits are between 18 m and 22 m

Question 88-29 : The total mass of an aeroplane is 145000 kg and the centre of gravity limits are between 47 m and 69 m aft of the datum the loaded centre of gravity position is 44 m afthow much mass must be transferred from the front to the rear hold in order to bring the out of limit centre of gravity position to ?

7500 kg.

Change in mass total mass = change in cg total distance movedchange in cg = 03 from 44 m to reach 47 m total distance moved = distance between front hold and rear hold = 87 m 29 m = 58 mchange in mass = total mass x change in cg total distance movedchange in mass = 145000 x 03 58 = 7500 kg

Question 88-30 : With respect to multi engine piston powered aeroplane determine the block fuel moment lbsin in the following conditions basic empty mass 3 210 lbsone pilot 160 lbsfront seat passenger 200 lbscentre seat passengers 290 lbs total one passenger rear seat 110 lbsbaggage in zone 1 100 lbsbaggage in zone ?

56160.

Block fuel 100 us gal x 6 lbs = 600 lbs 141600 x 936 = 56160

Question 88-31 : With respect to a multi engine piston powered aeroplane determine the total moment lbsin at landing in the following conditions basic empty mass 3210 lbsone pilot 160 lbsfront seat passenger 200 lbscentre seat passengers 290 lbs total one passenger rear seat 110 lbsbaggage in zone 1 100 lbsbaggage ?

401338 lbsin.

Take off moment 432226 lbsintrip fuel moment 55 x 6 = 330 330 x 936 = 30888 lbsinldg 432226 30888 = 401338 lbsin it's given take off moment so 3 us gal for start up and taxi has already been burned therefore 55 not 58

Question 88-32 : Determine the cg location at take off in the following conditions basic empty mass 3210 lbone pilot 160 lbfront seat passenger 200 lbcentre seat passengers 290 lb total one passenger rear seat 110 lbbaggage in zone 1 100 lbbaggage in zone 4 50 lbzero fuel mass 4120 lbmoment at zero fuel mass 377751 ?

9192 inches aft of datum.

Img141centre of gravity at take off = 4322262 4702 = 9192 aft of datum

Question 88-33 : With respect to a single engine piston powered aeroplane determine the zero fuel moment lbsin100 in the following conditions basic empty mass 2415 lbsarm at basic empty mass 779 incargo zone a 350 lbsbaggage zone b 35 lbspilot and front seat passenger 300 lbs total 204 ?

25488.

Img142

Question 88-34 : The aeroplane has a mass of 51 000 kg in the cruise the range of safe cg positions as determined from the appropriate graph in the loading manual is 1050 ?

Forward limit 4% aft limit 297% mac.

Question 88-35 : Considering the annex attached to the 50 000 kg mass determine the displacement of the front limit of the center of gravity when moving from the clean configuration to the flaps and landing gear landing configuration ?

The centre of gravity move back from 4% to 5% mac.

Question 88-36 : Using the weight and balance graph provided in the appendix determine the range of permissible center of gravity positions for the maximum landing weight of 56245 kg ?

From 5% to 292% mac.

Question 88-37 : Prior to departure an aircraft is loaded with 16500 litres of fuel at a fuel density of 078 this is entered into the load sheet as 16500 kg and calculations are carried out accordinglyas a result of this error the aircraft is ?

Lighter than anticipated and the calculated safety speeds will be too high.

The aircraft is lighter than anticipated 16500 kg entered into the load sheet instead of 12870 kg the calculated safety speeds v1 vr v2 will be too high they have been computed for an heavier aircraft you will get airborne earlier you will have much greater margins

Question 88-38 : An additional baggage container is loaded into the aft cargo compartment but is not entered into the load and trim sheetthe aeroplane will be heavier than expected and calculated take off safety speeds ?

Will give reduced safety margins.

Question 88-39 : Fuel loaded onto an aeroplane is 15400 kg but is erroneously entered into the load and trim sheet as 14500 kgthis error is not detected by the flight crew but they will notice that ?

Speed at which the airplane will leave the ground will be higher than expected.

The airplane is heavier than the pilots think it is v1 will be reached later the aeroplane will rotate later than expectedthe crew did not detect the error thus v1 will not change

Question 88-40 : Which of the following is unlikely to have any effect on the position of the centre of gravity on an aeroplane in flight ?

Changing the tailplane horizontal stabiliser incidence angle.

Trimming the stabiliser is a response to a cg change it does not move the cg