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## TODA

• Posts: 168

### Carello replied the topic: TODA

(b) the EOS local rule means that a stopway will be in the TODA for MOS 139 complying aerodromes.

I have a real problem with this proposition. To my mind, the local rule (MOS 5.2.2.1 b) only applies when a "stopway is not involved".

If proposition (b) were true, then TODA = TORA+Stopway+EOS/RESA. But the distance specified by the Stopway+EOS/RESA does not meet the criteria required for a clearway which means that proposition (b) must be false.

My apologies if the above is a "straw man" argument!

• John.Heddles
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• ATPL/consulting aero engineer
• Posts: 473

### John.Heddles replied the topic: TODA

To my mind, the local rule (MOS 5.2.2.1 b) only applies when a "stopway is not involved".

.. even if it explicitly states

Where there is no designated clearway (my bolding), the part of the runway strip between the end of the runway and the runway strip end is included as part of the TODA. This Australian practice has been registered with ICAO. ?

Your following logic, I suggest, is flawed. The reference offers the following options -

(a) if clearway exists, then TODA = TORA + clearway (and the clearway overlies the stopway)

(b) if clearway does not exist, then TODA = TORA + distance to EOS (and the distance to EOS overlies the stopway)

The final stopway reference, to this engineer, makes no logical sense at all - unless it is just emphasising that the stopway has no imperative.

How about I flick a question to the guys in Canberra and see if I can get an interpretation from the gurus ?

Engineering specialist in aircraft performance and weight control.

• Posts: 168

### Carello replied the topic: TODA

The final stopway reference, to this engineer, makes no logical sense at all - unless it is just emphasising that the stopway has no imperative.

To my knowledge the ICAO practice does not include the stopway in the TODA unless it (the stopway) lies under a clearway - see below.
The australian practice seems to modifies the ICAO practice by including the EoS/RESA when there is no stopway - my interpretation.

Unfortunately I have no idea what happens to the Australian practice when we do have a stopway and no clearway. Do we revert to the ICAO practice or something else?

How about I flick a question to the guys in Canberra and see if I can get an interpretation from the gurus ?

• Posts: 168

### Carello replied the topic: TODA

G'day Stuart

I had another look through your previous post and found something that might need clarification - refer to your text book graphic below

In the above graphic from the BT text, the grass area at the end of the strip is referred to as a "declared clearway". Is this technically correct in view of the Australian practice (MoS 5.2.2.1 b below) that defines TODA as TORA+EOS/RESA when no clearway is defined.

Oh what a web!

• Posts: 482

### Stuart Tait replied the topic: TODA

I have to admit I agree with John that the TODA in that question is 1510 as the end of strip negates any clearway or stopway and AD 1.1 para 4.7.1 adds at least 60m

But it's making my head spin when you start looking at the legislation

Cheers

• Posts: 168

### Carello replied the topic: TODA

I have to admit I agree with John that the TODA in that question is 1510 as the end of strip negates any clearway or stopway

And yet 1510m is not one of the multi-choice answers given in the question. I'm not say that 1510m is wrong; I am suggesting that MOS 5.2.2.1 b casts reasonable doubt on that answer.

Interestingly, if we applied the ICAO practice (see below) to the question, we get a simple answer, TODA=TORA=1350 - which is one of the listed answers. It makes one wonder where on the globe this question originated.

In practice, the answer to this question is a moot point. To my knowledge, all runways in Australia with a stopway have an overlying surveyed clearway. This gives the text book equation, TODA =TORA+Clearway.

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• John.Heddles
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• Posts: 473

### John.Heddles replied the topic: TODA

Again - caveat - I am not an aerodromes expert, although I have 50-odd years of playing in the Industry.

Some observations -

(a) have sent a question off to one of the CASA airports engineers - so we shall have to wait and see what sort of answer might eventuate.

(b) Unfortunately I have no idea what happens to the Australian practice when we do have a stopway and no clearway. Do we revert to the ICAO practice or something else?

ICAO words are recommended, not mandatory. It is expected that Contracting States observe the recommendations within local legislation. Where local protocols vary from ICAO recommendations, the State is expected to register the difference and publish relevant information in local documents - eg the AIP. It follows that, as local pilots, we use the local documents and rules (ie CASA and AirServices stuff in the main).

(c) In the above graphic from the BT text, the grass area at the end of the strip is referred to as a "declared clearway".

Clearway only exists for the pilot if it is specified by the aerodrome owner in ERSA. The MOS words will apply in general.

(d) TODA as TORA+EOS/RESA when no clearway is defined.

Possibly heading off at a bit of a tangent, here. The MOS indicates

Where there is no designated clearway, the part of the runway strip between the end of the runway and the runway strip end is included as part of the TODA. This Australian practice has been registered with ICAO.

Probably better not to try and paraphrase things too much ..

Some background words for interest -

(i) www.pprune.org/questions/275183-runway-e...ml?highlight=stopway This PPRuNe thread has some very expert engineers in the discussion. OverRun, no longer with us, unfortunately (died getting onto a couple of years ago, now), was a DCA airports engineer and, subsequently, had many years as a consultant and university academic - very much an airports expert, was our Prof. Emery .. as well as charming and entertaining company over a meal with like-minded aviation folk. If I recall correctly, he was the boss engineer for the present Broome Airport redevelopment.

(ii) www.icao.int/NACC/Documents/Meetings/2016/ACI/D1-05-RESA.pdf

(iii) www.icao.int/NACC/Documents/Meetings/201...F2/GRPECASF2-P09.pdf

.. and he probably will need to go next door and have a chat with the airports folks ...

(f) And yet 1510m is not one of the multi-choice answers given in the question.

That indicates that either the answers are wrong, or our logic is wrong. Hence the need to refer the matter to the gurus for adjudication ...

(g) Interestingly, if we applied the ICAO practice (see below) to the question, we get a simple answer,

Keep in mind that we don't use ICAO words unless the State has adopted them and, in any case, we use the local State words as they are what will hang us in Court after the event. In this case, there is a registered difference so the ICAO words are not specifically relevant.

(h) To my knowledge, all runways in Australia with a stopway have an overlying surveyed clearway.

Do you have some objective evidence for that statement ?

Engineering specialist in aircraft performance and weight control.

• Posts: 168

### Carello replied the topic: TODA

Do you have some objective evidence for that statement ?

I did find a table in an ATSB report - I will post the link if I can find it.

• Posts: 168

### Carello replied the topic: TODA

Do you have some objective evidence for that statement ?

Found it at www.atsb.gov.au/media/440007/ar2008018_2.pdf

Go to Appendix B page 94 onwards.

• John.Heddles
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• Posts: 473