Carello

Your profile picture is very apt regarding this subject

Cheers

G'day Stuart

I had to stop thinking about it - I beginning to get a headache!

Do you or Bob have any pearls of wisdom on this question? Does TODA include or exclude a stopway when there is NO clearway? The Aerodrome MoS looks to has a bob each way on this question - excuse the pun!

Cheers

Carello this is what we have in the book and I'll stick with it

[attachment=1513]Capture.PNG[/attachment]

Does not help a lot - but I know what you aren't saying !
Cheers

[The legislation links are not working at the moment so I'm having to rely on memory, so there may be some minor details to change ..]

(a) MOS 139 covers most aerodromes and ERSA will be compliant with the MOS requirements ie, the MOS calls the shots in most situations.

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

(c) TORA is a confusing one for light aircraft pilots as it is of no certification relevance to small aeroplanes. Rather it only plays a part in heavy aircraft performance. CAO 20.7.1b refers in the local context although that is another story altogether ...

TORA is definitely NOT there to provide a lift off point at the end of the TORA. In any case, the light aircraft POH doesn't provide any information to allow the calculation of such a procedure.

For heavy aircraft, the initial part of the takeoff flare to screen height (normally 35 ft in lieu of 50 ft for lighties) has to be over the TORA and the latter part may be over the clearway. Depending on the rules, the ratio normally is 1:1 but, for older UK rules, it may be 1:2. That is to say, the TORA/TODA setup provides that the aircraft, barring major problems, will be airborne some distance prior to the end of the declared TORA and at/above screen height by the end TODA. The whole of the clearway distance may not be usable by a given aircraft performance requirement.

So how should one try to resolve the problems ?

(a) first, it is manifestly and potentially hazardous just to blindly use the declared TODA for a light aircraft if there is a significant declared clearway. This is due to the comparatively short air distance to screen for a light aircraft. Typically, AEO, the lightie should be doing better than 6% which suggests an air distance somewhat less than 1000 ft. Hence, if you have an unsuitable set of data, you could find yourself still on the ground in the clearway .. and that could be rather less than nice. It is unfortunate that the light aircraft rules don't think about this at all.

(b) my practice is to know the expected performance numbers and make sure that I am not trying to use more than, say, 150 metres of nominal clearway. For most runways where TORA is declared, this won't be a problem as the TODR will be less than the TORA. However, do be careful as there is the possibility that you can bite yourself and badly if you don't think a bit about what you are doing.

So far as transient obstructions are concerned, the clearway will be under the control of the aerodrome authority.

The often seen 60m difference between TORA and TODA covers the RESA requirement under the old standards. These are in the midst of a long term change but it will be a while before the new standards prevail generally. In the meantime, 60m is a savings clause letout.

In general, aerodromes stuff is the material of airports experts and we pilots (even if in the guise of performance engineers) are often likely to get the finer details of the aerodrome design rules mixed up to some degree.

[color=blue](b) the EOS local rule means that a stopway will be in the TODA for MOS 139 complying aerodromes.[/color]

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 [color=blue](b)[/color] 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 [color=blue](b)[/color] must be false.

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

[color=blue][i][b]To my mind, the local rule (MOS 5.2.2.1 b) only applies when a "stopway is not involved".[/b][/i][/color]

.. even if it explicitly states

[i][color=red][b]Where there is no designated clearway[/b][/color] (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.[/i] ?

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 ?

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

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?

[attachment=1515]ICAO TODA.PNG[/attachment]

[color=blue]How about I flick a question to the guys in Canberra and see if I can get an interpretation from the gurus ?[/color]
Yes please!

G'day Stuart

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

[hr]

[attachment=1517]TORA TextBook.png[/attachment]

[hr]

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 [u]no clearway is defined[/u].

[hr]

[attachment=1518]TODA_2019-05-10.png[/attachment]

Oh what a web!

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

I'll have to ask Gavin about that one

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

Cheers

[color=blue]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
[/color]
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.

[attachment=1519]ICAO TODA.PNG[/attachment]

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) [color=blue][i][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?[/b][/i][/color]

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) [color=blue][i][b]In the above graphic from the BT text, the grass area at the end of the strip is referred to as a "declared clearway".[/b][/i][/color]

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

(d) [color=blue][i][b]TODA as TORA+EOS/RESA when no clearway is defined.[/b][/i][/color]

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

[color=blue][i][b]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.[/b][/i][/color]

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

Some background words for interest -

(i) https://www.pprune.org/questions/275183-runway-end-safety-areas-resa.html?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) https://www.icao.int/NACC/Documents/Meetings/2016/ACI/D1-05-RESA.pdf

(iii) https://www.icao.int/NACC/Documents/Meetings/2015/GREPECASPF2/GRPECASF2-P09.pdf

(e) [color=blue][i][b]I'll have to ask Gavin about that one[/b][/i][/color]

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

(f) [color=blue][i][b]And yet 1510m is not one of the multi-choice answers given in the question.[/b][/i][/color]

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) [color=blue][i][b]Interestingly, if we applied the ICAO practice (see below) to the question, we get a simple answer,[/b][/i][/color]

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) [color=blue][i][b]To my knowledge, all runways in Australia with a stopway have an overlying surveyed clearway.[/b][/i][/color]

Do you have some objective evidence for that statement ?

[color=blue]Do you have some objective evidence for that statement ?
[/color]

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

[color=blue]Do you have some objective evidence for that statement ?
[/color]
Found it at https://www.atsb.gov.au/media/440007/ar2008018_2.pdf

Go to Appendix B page 94 onwards.

Ah, thanks for that, very much ... I don't recall having seen that report before. I'll have a read tomorrow over coffee.

[i](How fine to see that our good OverRun (Steve Emery) gets a few credits in the document).[/i]