Reading 20.7.1B, 7 Take-off climb performance
One of the problems for newer folk is an absence of the history. You are reading too much airworthiness significance into 20.7.1B when that is not what it was about originally.
20.7.1B is an operational CAO (originally ANO) and was recast from the airworthiness orders (ANO 101.5/101.6) many decades ago by non-airworthiness folk who didn't always get the story quite aligned with the original.
In turn 101.5/101.6 were based on the UK/FAA airworthiness rules (or was it the other way around ? .. so long ago now, the memory might have the two reversed). Either way, 101.5/101.6 were consigned WPB post Ron Yeats' efforts some years ago. As a consequence, the only words Oz pilots now have available are in 20.7.1B which is a bit sad in this writer's view - it certainly causes problems on occasion.
The CAO never mentions the term "segment" for what we all refer to as 1st, 2nd, 3rd, 4th segment.
However, if you read back to the original O/S documents, you will find references to an option to develop the takeoff NFP by a segmental approach … eg, see the current FAR 25.111(d)
https://www.ecfr.gov/cgi-bin/text-idx?SID=16c7974b0f68b39ce0e9da3885b669a5&mc=true&node=se14.1 .25_1111&rgn=div8
Some aircraft even have a 5th final acceleration segment (eg AW650 under the UK rules).
7.3.1 and 7.3.2 refer to the "level flight acceleration manoeuvre", what we'd call 3rd segment, as commencing at a minimum of 400ft.
.. and 400 ft goes back somewhat further to the ICAO PAMC on Performance, if my recollection is correct, a document to which reference is made on occasion in PPRuNe.
And then back to 7.1. It states " In the take-off configuration assuming failure of the critical engine so that it is recognised at V1
After realising that far too many overruns were occurring on critical runways, that V1 idea went out some years ago in favour of the concept that V1 coincides with the application of the first element of the rejection process and the now common cry that "if you haven't started stopping by V1, then you're going .." (with the failure having occurred at Vef). See, for instance,
https://www.faa.gov/other_visit/avia...off_safety.pdf
There is nothing here that states "commences only at 35ft" or "commencing from the end of TOD".
But do have a read of FAR 25.115(a)
https://www.ecfr.gov/cgi-bin/text-idx?SID=255d3b6cad33ff9c83537e34c8670de5&mc=true&node=se14.1 .25_1115&rgn=div8
The implication is that the flight path from runway to
I really think that you need to re-read the CAO a little more critically and, also, read it in conjunction with the foreign rules from which, ultimately, it derives.
But also "first segment" consideration must apply from the moment the aircraft leaves the ground
If you read all the story, rather than the bits you might choose to support your position, you might relax it a little bit ? The TODR element covers getting to screen, first segment, should it exist, covers the final bit of gear retraction, should that not have been completed by screen. There are words in the airworthiness standards which require positive gradient (capability) at all stages of the takeoff and takeoff flight path. See, example FAR 25.111(a) and (c)(1)
One of the main problems with the present setup is that the design rules which went into the certification of various Types, change. So, Type A met a different set of rules (the frozen design standards) than did Type B.
Ergo, one looks up the TCDS to find out what set of rules are applicable. 20.7.1B gives no regard to this. As a consequence, how does the pilot figure out if his/her aircraft AFM actually has any resemblance to whatever 20.7.1B has to say ? Those of us with a suitable background can make a reasonable attempt with some relevant sums but, for the typical pilot, and his FOI who probably doesn't have the background either, both are probably a bit at sea ?
I'm afraid this writer has the idea that Ron missed the boat in the aspect of rubber stamping overseas standards for certification … without introducing any pragmatic means for the local Oz operators and pilots to relate the local rules back to the foreign NAA requirements. I am not aware that this problem has been tested in Court as yet but, if not, it will come eventually and then there will, no doubt, be egg on face in various quarters .. Ron, I suspect, was mainly driven by consideration of QF's situation and, unfortunately, the wider Industry got left behind in the process. I'm not having a go at Ron, he was a fine chap. However, the follow on from his Report didn't dot all the i's and cross all the t's as it could have done ..