ATPL TODA & LDA slope corrections
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ATPL TODA & LDA slope corrections
Hi all,
My ATPL performance and loading notes state that for LDA when using forecast conditions, "it is assumed that the aircraft will land on the most favorable RWY (longest one) and direction available (up slope) and that no headwind component will be available for landing". As such, when using forecast conditions, it states that no LDA reduction for down slope is required.
It references CAO 20.7.1(B) Section 4.1 (d), but I have trolled my way through the whole CAO and can't find anything suggesting such an assumption.
If anyone could confirm what is expected for the exam and, ideally, point me to the CAO reference, it would be appreciated.
There is also no mention in the notes regarding what to do with TODA if forecast conditions are given (ie can headwind component be used as part of your calculations)
Thanks in advance
My ATPL performance and loading notes state that for LDA when using forecast conditions, "it is assumed that the aircraft will land on the most favorable RWY (longest one) and direction available (up slope) and that no headwind component will be available for landing". As such, when using forecast conditions, it states that no LDA reduction for down slope is required.
It references CAO 20.7.1(B) Section 4.1 (d), but I have trolled my way through the whole CAO and can't find anything suggesting such an assumption.
If anyone could confirm what is expected for the exam and, ideally, point me to the CAO reference, it would be appreciated.
There is also no mention in the notes regarding what to do with TODA if forecast conditions are given (ie can headwind component be used as part of your calculations)
Thanks in advance
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Subject to your particular rules (or exam protocols) and SOPs, the aim is to be conservative and cover all bases so that any surprises are reserved for the bar on the overnight rather than the aerodrome arrival ...
Hence, the usual approach is to look to nil wind on the most suitable runway unless the forecast may result in an excessive crosswind. In that case one would check for the lesser RLW of the nil wind case and an into wind runway with a headwind equivalent to that maximum crosswind.
Although I've not seen it done so, a similar approach might be adopted were the forecast to provide an excessive tailwind on the preferred runway .. again, in an effort to cover the all bases consideration.
As to slope, the preferred runway chosen for the calculation will cause whatever slope exists to be considered. The AFM should have slope and factored wind correction grids included.
TOD calculations are not the problem - if you guessed wrong or the forecast turns out to be non-conservative, you offload fuel or payload or wait for more suitable conditions. The significance about the landing calculation is that you will be in flight and don't have the opportunity of waiting around all day or, in many cases, diverting to a variety of alternates ergo you need to have a plan figured out in advance.
Hence, the usual approach is to look to nil wind on the most suitable runway unless the forecast may result in an excessive crosswind. In that case one would check for the lesser RLW of the nil wind case and an into wind runway with a headwind equivalent to that maximum crosswind.
Although I've not seen it done so, a similar approach might be adopted were the forecast to provide an excessive tailwind on the preferred runway .. again, in an effort to cover the all bases consideration.
As to slope, the preferred runway chosen for the calculation will cause whatever slope exists to be considered. The AFM should have slope and factored wind correction grids included.
TOD calculations are not the problem - if you guessed wrong or the forecast turns out to be non-conservative, you offload fuel or payload or wait for more suitable conditions. The significance about the landing calculation is that you will be in flight and don't have the opportunity of waiting around all day or, in many cases, diverting to a variety of alternates ergo you need to have a plan figured out in advance.
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Your question refers to LDA and TODA.
The CAO defines them and they are fixed distances. They don't change and you don't factor them in any way.
LDR and TODR do you mean? Performance data for your aircraft should have factors or an ability to allow for slope.
Regarding slope, the CAO has this (my bold):
5 LANDING WEIGHT LIMITATIONS
5.1 For the purposes of paragraph 235 (2) (b) of the Regulations, the maximum
weight which an aeroplane to which this section applies may not exceed at
landing is the least of the weights determined in accordance with
subparagraphs (a) to (c):
(a) a weight at which the landing distance required in accordance with
subsection 11 for the aerodrome elevation, wind component along the
runway, runway slope (when exceeding 1%) and runway surface
conditions at the time of landing, is equal to or less than the landing
distance available in the direction of landing;
(b) a weight which will permit compliance with the approach climb
requirements specified in subsection 9, taking into account forecast or
ambient temperature and aerodrome elevation or approved declared
conditions;
(c) a weight which will permit compliance with the landing climb
requirements specified in subsection 10 taking into account forecast or
ambient temperature and aerodrome elevation or approved declared
conditions.
The CAO defines them and they are fixed distances. They don't change and you don't factor them in any way.
LDR and TODR do you mean? Performance data for your aircraft should have factors or an ability to allow for slope.
Regarding slope, the CAO has this (my bold):
5 LANDING WEIGHT LIMITATIONS
5.1 For the purposes of paragraph 235 (2) (b) of the Regulations, the maximum
weight which an aeroplane to which this section applies may not exceed at
landing is the least of the weights determined in accordance with
subparagraphs (a) to (c):
(a) a weight at which the landing distance required in accordance with
subsection 11 for the aerodrome elevation, wind component along the
runway, runway slope (when exceeding 1%) and runway surface
conditions at the time of landing, is equal to or less than the landing
distance available in the direction of landing;
(b) a weight which will permit compliance with the approach climb
requirements specified in subsection 9, taking into account forecast or
ambient temperature and aerodrome elevation or approved declared
conditions;
(c) a weight which will permit compliance with the landing climb
requirements specified in subsection 10 taking into account forecast or
ambient temperature and aerodrome elevation or approved declared
conditions.
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Hi tic-nat,
It seems to me that your post includes statements similar to EU performance planning law. Waren9 has a definitive answer for Aust conditions. Are your ATPL notes perhaps published overseas and "adapted" for Australia?
Cheers, O8
It seems to me that your post includes statements similar to EU performance planning law. Waren9 has a definitive answer for Aust conditions. Are your ATPL notes perhaps published overseas and "adapted" for Australia?
Cheers, O8
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Thanks all,
The extract quoted by Warren is the only one I could find and it doesn't make any differentiation between forecast vs actual wind, so I think I'll include slope over 1% (which is also what the CASA 727 POH manual says). Hopefully I don't get a question that involves excessing slope.
The extract quoted by Warren is the only one I could find and it doesn't make any differentiation between forecast vs actual wind, so I think I'll include slope over 1% (which is also what the CASA 727 POH manual says). Hopefully I don't get a question that involves excessing slope.
