Chapter 4—Flight preparation (Part 121 aChapter 4—Flight preparation (Part 121 alternate aerodromes) requirements

Chapter 4—Flight preparation (Part 121 alternate aerodromes) requirements

Division 1—Preliminary

4.01 Scope of Chapter 4

This Chapter: (a) is made for subregulation 121.170(1) of CASR; and (b) prescribes the flight preparation (Part 121 alternate aerodromes) requirements.

4.03 Definition of isolated destination aerodrome

(1) A planned destination aerodrome is an isolated destination aerodrome for an aeroplane if the amount of fuel, mentioned in subsection (2), for a flight: (a) from the planned destination aerodrome; and (b) to the nearest aerodrome that would meet the requirements for a destination alternate aerodrome (the relevant aerodrome) for the aeroplane under the civil aviation legislation; is greater than the amount mentioned in subsection (3).

Note: For an aerodrome to be a destination alternate aerodrome, it must also (in addition to meeting the applicable requirements under this Chapter) meet other requirements that apply for aerodromes under this instrument, Division 121.D of CASR, Part 91 of CASR or in other provisions of the civil aviation legislation.

(2) For subsection (1), the amount is the sum of:

(a) the fuel required to:
(i) perform a missed approach at the planned destination aerodrome; and
(ii) climb to the expected cruising altitude; and
(iii) fly the expected routing to the relevant aerodrome; and
(iv) descent to the point where the expected approach is initiated; and
(v) land at the relevant aerodrome; and
(b) the final reserve fuel.

(3) For subsection (1), the amount is: (a) for a piston-engine aeroplane—the lesser of: (i) the fuel required to fly for 45 minutes plus the fuel to fly for 15% of the flight time spent at the planned cruising level between the departure aerodrome and the planned destination aerodrome; and (ii) 2 hours; or (b) for a turbine-engine aeroplane—the fuel required to fly the aeroplane for 2 hours at the planned cruising level above the planned destination aerodrome, including final reserve fuel.

4.04 Definition of relevant weather conditions

(1) In this Chapter, the following weather conditions are the relevant weather conditions:

(a) in relation to cloud—the cloud is more than SCT;
(b) visibility, including a probability indicator of at least 30% or greater of fog, mist, dust or any other phenomenon restricting visibility;
(c) in relation to wind—a headwind, crosswind or downwind component more than the maximum for the aeroplane, including any forecast wind gusts;
(d) a thunderstorm or its associated severe turbulence, or at least a probability of 30% or greater of a thunderstorm or its associated severe turbulence.

Holding fuel—operationally limiting weather conditions (2) Despite subsection (1), if relevant weather conditions would represent an operationally limiting condition, the weather is taken not to be present if, for the flight, the aeroplane carries the amount of holding fuel mentioned in subsection (3). (3) For subsection (2), and subject to subsections 4.06(4) to (7), the amount of holding fuel must be at least equal to the number of minutes of the period of the overlap of: (a) the estimated time of use; and (b) the time at which the operationally limiting weather conditions would no longer apply to the flight.