NCC.POL.105 Mass and balance, loading

CENTRE OF GRAVITY LIMITS — OPERATIONAL CG ENVELOPE AND IN-FLIGHT CG In the Certificate Limitations section of the AFM, forward and aft CG limits are specified. These limits ensure that the certification stability and control criteria are met throughout the whole flight and allow the proper trim setting for take-off. The operator should ensure that these limits are respected by:

(a)Defining and applying operational margins to the certified CG envelope in order to compensate for the following deviations and errors:

(1)Deviations of actual CG at empty or operating mass from published values due, for example, to weighing errors, unaccounted modifications and/or equipment variations.

(2)Deviations in fuel distribution in tanks from the applicable schedule.

(3)Deviations in the distribution of baggage and cargo in the various compartments as compared with the assumed load distribution as well as inaccuracies in the actual mass of baggage and cargo.

(4)Deviations in actual passenger seating from the seating distribution assumed when preparing the mass and balance documentation. Large CG errors may occur when ‘free seating’, i.e. freedom of passengers to select any seat when entering the aircraft, is permitted. Although in most cases reasonably even longitudinal passenger seating can be expected, there is a risk of an extreme forward or aft seat selection causing very large and unacceptable CG errors, assuming that the balance calculation is done on the basis of an assumed even distribution. The largest errors may occur at a load factor of approximately 50 % if all passengers are seated in either the forward or aft half of the cabin. Statistical analysis indicates that the risk of such extreme seating adversely affecting the CG is greatest on small aircraft.

(5)Deviations of the actual CG of cargo and passenger load within individual cargo compartments or cabin sections from the normally assumed mid position.

(6)Deviations of the CG caused by gear and flap positions and by application of the prescribed fuel usage procedure, unless already covered by the certified limits.

(7)Deviations caused by in-flight movement of cabin crew, galley equipment and passengers.

(b)Defining and applying operational procedures in order to:

(1)ensure an even distribution of passengers in the cabin;

(2)take into account any significant CG travel during flight caused by passenger/crew movement; and

(3)take into account any significant CG travel during flight caused by fuel consumption/transfer.

WEIGHING OF AN AIRCRAFT

(a)New aircraft that have been weighed at the factory may be placed into operation without reweighing if the mass and balance records have been adjusted for alterations or modifications to the aircraft. Aircraft transferred from one EU operator to another EU operator do not have to be weighed prior to use by the receiving operator, unless the mass and balance cannot be accurately established by calculation.

(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 ±0.5 % of the maximum landing mass or for aeroplanes the cumulative change in CG position exceeds 0.5 % of the mean aerodynamic chord. This should be done either by weighing the aircraft or by calculation.

(c)When weighing an aircraft, normal precautions should be taken, which are 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 building.

(d)Any equipment used for weighing should be properly calibrated, zeroed and used in accordance with the manufacturer's instructions. Each scale should be calibrated either by the manufacturer, by a civil department of weights and measures or by an appropriately authorised organisation within 2 years or within a time period defined by the manufacturer of the weighing equipment, whichever is less. The equipment should enable the mass of the aircraft to be established accurately. One single accuracy criterion for weighing equipment cannot be given. However, the weighing accuracy is considered satisfactory if the accuracy criteria in Table 1 are met by the individual scales/cells of the weighing equipment used: Table 1: Accuracy criteria for weighing equipment

DRY OPERATING MASS

(a)The dry operating mass should include:

(1)crew and crew baggage;

(2)catering and removable passenger service equipment; and

(3)tank water and lavatory chemicals.

(b)The operator should correct the dry operating mass to account for any additional crew baggage. The position of this additional baggage should be accounted for when establishing the centre of gravity of the aircraft.

(c)The operator should establish a procedure in the operations manual to determine when to select actual or standard masses for crew members.

(d)When determining the actual mass by weighing, crew members’ personal belongings and hand baggage should be included. Such weighing should be conducted immediately prior to boarding the aircraft.

MASS VALUES FOR PASSENGERS AND BAGGAGE

(a)The predetermined mass for hand baggage and clothing should be established by the operator on the basis of studies relevant to its particular operation. In any case, it should not be less than:

(1)4 kg for clothing; and

(2)6 kg for hand baggage. The passengers’ stated mass and the mass of passengers’ clothing and hand baggage should be checked prior to boarding and adjusted, if necessary. The operator should establish a procedure in the operations manual when to select actual or standard masses and the procedure to be followed when using verbal statements.

(b)When determining the actual mass by weighing, passengers’ personal belongings and hand baggage should be included. Such weighing should be conducted immediately prior to boarding the aircraft.

(c)When determining the mass of passengers by using standard mass values, provided in Tables 1 and 2 of NCC.POL.105(e), infants occupying separate passenger seats should be considered as children for the purpose of this AMC. When the total number of passenger seats available on an aircraft is 20 or more, the standard masses for males and females in Table 1 of NCC.POL.105(e) should be used. As an alternative, in cases where the total number of passenger seats available is 30 or more, the ‘All Adult’ mass values in Table 1 of NCC.POL.105(e) may be used. On aeroplane flights with 19 passenger seats or less and all helicopter flights where no hand baggage is carried in the cabin or where hand baggage is accounted for separately, 6 kg may be deducted from male and female masses in Table 2 of NCC.POL.105(e). Articles such as an overcoat, an umbrella, a small handbag or purse, reading material or a small camera are not considered as hand baggage. For helicopter operations in which a survival suit is provided to passengers, 3 kg should be added to the passenger mass value.

(d)Mass values for baggage. The mass of checked baggage should be checked prior to loading and increased, if necessary.

(e)On any flight identified as carrying a significant number of passengers whose masses, including hand baggage, are expected to significantly deviate from the standard passenger mass, the operator should determine the actual mass of such passengers by weighing or by adding an adequate mass increment.

(f)If standard mass values for checked baggage are used and a significant number of passengers’ checked baggage is expected to significantly deviate from the standard baggage mass, the operator should determine the actual mass of such baggage by weighing or by adding an adequate mass increment.

ADJUSTMENT OF STANDARD MASSES When standard mass values are used, item (e) of AMC1 NCC.POL.105(d) states that the operator should identify and adjust the passenger and checked baggage masses in cases where significant numbers of passengers or quantities of baggage are suspected of significantly deviating from the standard values. Therefore, the operations manual should contain instructions to ensure that:

(a)check-in, operations and loading personnel as well as cabin and flight crew report or take appropriate action when a flight is identified as carrying a significant number of passengers whose masses, including hand baggage, are expected to significantly deviate from the standard passenger mass, and/or groups of passengers carrying exceptionally heavy baggage; and

(b)on small aircraft, where the risks of overload and/or CG errors are the greatest, pilots pay special attention to the load and its distribution and make proper adjustments.

TYPE OF FLIGHTS

(a)For the purpose of Table 3 of NCC.POL.105(e):

(1)domestic flight means a flight with origin and destination within the borders of one State.

(2)flights within the European region means flights, other than domestic flights, whose origin and destination are within the area specified in item (b).

(3)Intercontinental flight means flights beyond the European region with origin and destination in different continents.

(b)Flights within the European region are flights conducted within the following area: N7200 E04500 N4000 E04500 N3500 E03700 N3000 E03700 N3000 W00600 N2700 W00900 N2700 W03000 N6700 W03000 N7200 W01000 N7200 E04500 as depicted in Figure 1: European region.

Figure 1: The European region [Figure or form omitted from this preview — available in the Avioverse workspace library.]

FUEL DENSITY

(a)If the actual fuel density is not known, the operator may use standard fuel density values for determining the mass of the fuel load. Such standard values should be based on current fuel density measurements for the airports or areas concerned.

(b)Typical fuel density values are:

(1)Gasoline (reciprocating engine fuel) – 0.71

(2)JET A1 (Jet fuel JP 1) – 0.79

(3)JET B (Jet fuel JP 4) – 0.76

(4)Oil – 0.88