Take-off and landing requirements
Weight and balance CAR 235, CAO 20.7.4
CASA may give directions as to how to estimate or determine the weight and centre of gravity of a particular aircraft and may require changes to the published weight and centre-of-gravity limits.
These limitations are found in the aircraft flight manual or placard information and must be complied with during all stages of flight.
In determining the maximum weight and centre of gravity limits, CASA may take into consideration:
- the type of aircraft
- the kind of operations to be carried out during the flight
- the performance of the aircraft in configurations in which it is likely to be flown, and with faults that are likely to occur
- the meteorological conditions at the aerodromes at which the aircraft is to take off or land
- the altitude of the aerodromes at which that aircraft is to take off or land
- the aerodrome dimensions in the direction in which the aircraft is to take off or land
- the material of which the surface of the aerodrome in the direction in which the aircraft is to take off or land is constituted and the condition and slope of that surface
- the presence of obstacles in the vicinity of the flight path along which the aircraft is to take off, approach or land
- the anticipated meteorological conditions over the intended route to be flown by the aircraft after take-off and over planned divergences from that route and
- the altitude of the terrain along and on either side of the intended route to be flown by the aircraft after take-off and of planned deviations from that route.
An aircraft must not take off, or attempt to take off, if its gross weight exceeds its maximum take-off weight or, if a lesser weight determined in accordance with a direction under CAR 235 is applicable to the take-off, that lesser weight.
An aircraft must not take off, or attempt to take off, if its gross weight exceeds, by more than the weight of fuel that would normally be used in flying to its next landing place or planned alternative aerodrome, its maximum landing weight; or if a lesser weight determined in accordance with a direction under CAR 235 is applicable to landing at that place or aerodrome, that lesser weight.
Except in an emergency, an aircraft must not land if its gross weight exceeds its maximum landing weight or, if a lesser weight determined in accordance with a direction under CAR 235 is applicable to the landing, that lesser weight.
An aircraft must not take off, or attempt to take off, unless any directions with respect to the loading of the aircraft given under the regulations have been complied with.
The pilot in command must ensure that the load of an aircraft throughout a flight shall be so distributed that the centre of gravity of the aircraft falls within the limitations specified in its certificate of airworthiness or its flight manual.
CAAP 235 reiterates the safety precautions that should be used to ensure compliance with CAR 235. It includes directions on how to determine runway clearance factors.
Determining weight limitations with meteorological conditions
CAR 235 requires the consideration of meteorological conditions when determining aircraft weight limitations for take-off and landing. The meteorological information to be used for determining weight limitations is as follows (CAO 20.7.4 para 4 and 5):
- for take-off
- ambient meteorological conditions, or
- approved declared conditions, and
- for landing
- forecast meteorological conditions, or
- approved declared conditions.
it is acceptable to base all take-off and landing weight limitation calculations on declared meteorological conditions (see below) alone and you may only be required to determine weight limitations three times per year (for summer, winter and autumn/spring seasons). However, if calculations based on declared conditions result in a take-off or landing weight limitation that is too restrictive for a flight to or from a particular aerodrome, recalculating weight limitations based on ambient (for take-off weight) or forecast (for landing weight) conditions may result in acceptable weight limitations for your flight.
Declared density chart CAO 20.7.0
Declared density chart – Summer (December–February)
Declared density charts are one acceptable means of determining take off and landing weight limitations at an aerodrome. There are three charts: one for summer months, one for winter months and one for both autumn and spring months.
The lines on the charts indicate lines of equal density altitude at the location of the aerodrome. However, these density altitude values do not take into account ground elevation and the values are assumed to be true at mean sea level. Therefore, you must add the aerodrome elevation to the declared density value at the appropriate location on the chart and then use this sum for take off and landing weight limitation calculations.
Declared density chart – Winter (June–August)
In some cases, the take off and landing weight limitation charts in some aircraft flight manuals require you to use the combination of pressure height (PH) and ambient outside air temperature (OAT) in order to determine weight limitations. In this case, you can assume international standard atmosphere (ISA) temperature for these calculations, thus the PH will be declared density (read off the declared density chart) plus field elevation, and then use ISA OAT for the field elevation.