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TODA

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Stew bond created the topic: TODA

Hi Everyone

Came across this question which seems to be causing me unexpected problems in two exams now.

TORA 1350M
ASDA 1450M with no "other" clearway
Displaced threshold 50M
What is the TODA

From what I've read TODA needs to have a surveyed clearway which is doesn't specifically state in the question.
Might be the wording or I'm just overthinking this one but don't appear to be clear in my head what the answer is?

Thanks
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John.Heddles replied the topic: TODA

First, have a read of Chapters 5 and 6 in this document - www.legislation.gov.au/Details/F2017C00087

Caveat - I'm not an airports expert but the general approach would be in keeping with the following -

TORA 1350M - the hard, usable, and generally used, part of the runway.
ASDA 1450M - with no other information, assume that the TORA/ASDA start at the same point so this indicates a stopway of (1450-1350) = 100 m
with no "other" clearway - but note that there may be other distance available to the strip end which usually would go into the TODA. However, in the absence of any information, presume that the strip ends at the end of the stopway .. that wouldn't be usual (there should be a graded area around the runway/stopway) but it's about all one can deduce from this set of information. See also 6.2.17.1 in the previously cited document.
Displaced threshold 50M - usually only of relevance for the LDA, so ignore this bit
What is the TODA - my take is one of TORA + stopway = 1350 + 100 = 1450 m or 1480m (+30) or 1510m (+60), depending on how you want to handle/incorporate 6.2.17.1. Also, consider AIP AD 1.1 - 12, p4.7.1. Overall, 1510m is looking strong for this question, methinks.

As a matter of interest, what was the exam question's answer ?

From what I've read TODA needs to have a surveyed clearway a specific clearway may exist but is not a necessary thing to have which is doesn't specifically state in the question.

Engineering specialist in aircraft performance and weight control.
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Stew bond replied the topic: TODA

Hi John

Thanks for the reply working through the possibilities....all of which I've considered.

The choice of answers were:

1300m
1350m
1400m
1450m

So I'm still at a loss as to how to figure this out without any clear understanding of how long the clearway is.

Interestingly, in my KDR, this one came out as "relationship between LDA and TORA" which doesn't seem appropriate to the question but since there were no other questions relating to both, not sure what else it could be.

Cheers

Stewart
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John.Heddles replied the topic: TODA

Stewart,

1300m

That's a distractor based on TORA - displacement (1350-50) which is irrelevant to anything much here

1350m

That's a simple cop-out distractor - let's make it the same as TORA - after all, that's the hard bit. Again, irrelevant.

1400m

That's a "having a bob each way" distractor based on using the ASDA, rather than the TORA and applying the displacement. Irrelevant.

1450m

This is the one which makes sense. Based on the MOS requirement of TORA + C/W. In this case, there is no specific C/W but we can take S/W as providing C/W. However, there still is the graded area problem, in this case at 6.2.16.1. Exam questions aside, I still think the answer should be either 1480/1510m.

I am a bit surprised as I would have expected a pilot-centric exam to have required an answer consistent with the AIP reference I quoted earlier. Such is life, I guess.

So I'm still at a loss as to how to figure this out without any clear understanding of how long the clearway is.

Have another read of the MOS words. If there is no defined clearway, the stopway, being located under the initial part of a clearway, can be considered as clearway. Hence, in this case, the clearway is the same distance as the stopway.

Interestingly, in my KDR, this one came out as "relationship between LDA and TORA" which doesn't seem appropriate to the question but since there were no other questions relating to both, not sure what else it could be.

Not much sense in that, is there ? I wouldn't fuss too much. Just read it to mean that they had a problem with your appreciation of runway distances.

Engineering specialist in aircraft performance and weight control.
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Stew bond replied the topic: TODA

Hi John

Many thanks for your time in resolving this issue for me.

I guess, if the question arises again in my next exam, I'll opt for 1450m.

I struggled with the definition because there was no defined "clearway" and a "stopway" hasn't been given the status of being able to be considered as a "clearway" in any material that I've read....again, I guess I shouldn't over analyse!

Thanks again for your time.

Stewart
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John.Heddles replied the topic: TODA

a "stopway" hasn't been given the status of being able to be considered as a "clearway" ..

More by inference. Consider the MOS words which indicate that, where there is no defined clearway, the remaining distance to the EOS is included in the TODA. Strictly, the stopway may not be of sufficient width to meet clearway requirements but the general words before address the situation, methinks.

Engineering specialist in aircraft performance and weight control.
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Carello replied the topic: TODA

TORA 1350M
ASDA 1450M with no "other" clearway
Displaced threshold 50M
What is the TODA


Given the lack of detail in this question, I would suggest that the TODA = TORA =1350 meters.

My reasoning is a follows:
1) As the displaced threshold is not a temporary displacement the runway distances specified in the question are correct.
2) A clearway is not a stopway and vice versa. Unless otherwise stated we can only assume that this runway has no clearway.

A simple answer to a vague question.
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John.Heddles replied the topic: TODA

A simple answer to a vague question.

Indeed .. but, necessarily, must be incorrect as it is inconsistent with the MOS - which is the relevant standard for aerodromes in Australia. Really, there appears to be no correct answer per the MOS words.

Engineering specialist in aircraft performance and weight control.
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Carello replied the topic: TODA

G'day John

In reference to your previous post, which words in the MoS are you referring to.

The MoS clearly states that a clear clearway starts at the end of the runway - see MoS 6.2.31.1 (cited below)



Now, since we cannot deduce that the runway in question has a CW, it follows that TORA = TODA = 1350 m

Your thoughts/comments would be appreciated!

Cheers
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Carello replied the topic: TODA

G'day John

I've done a little more digging and found the following in the MoS at 5.2.2.1



It would appear that in oz, the TODA does include the runway end strip but not the stopway.

Furthermore, the diagram in 5.2.2.2 (below), then goes on to contradict 5.2.2.1 above, by including the stopway in the diagram




I give up!
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