Important to all Procedure designers

28.10.2004

Answer or Commentary:

(I.W.

I have just received the amendment to Pans-Ops proposed by OCP 13. It seems that ICAO has decided to put the ILS OAS constants on CD-ROM and commissioned a software company to develop software to calculate the constants automatically (definitely a good idea). However it was interesting to see a short paragraph that I think most procedure designers and ICAO them selves missed or did not realise it's importance.


Paragraph 21.4.8.5

Note. - The PANS-OPS OAS CD-ROM also contains an OCH calculator that will show height of the OAS surface Z above any X, Y location. It includes all the adjustments specified for ILS geometry, aircraft dimensions, missed approach climb gradient and ILS reference datum height.


This paragraph raises some interesting questions.

1. Is the software going to be provided to the states free of charge like the CRM or will it have to be purchased? What will happen if bugs are found in this OCH calculator, does one have to purchase an upgrade?

2. I hope that documentation will be available as to who checked this OCH calculator and will the checking agency take responsibility in the case of a court case? The ICAO CRM software for example was tested for a long period of time by the NLR, an independent state run checker.

3. Does ICAO realise that they are endorsing a procedure design tool by putting reference to it in Doc. 8168 and including it on an ICAO CD_ROM. ICAO could be open to a court action after an accident that could be attributed to incorrect values being generated by this OCH calculator?

4. If ICAO now endorses one OCH calculator why not endorse all the other OCH calculators out there (Intergraph, PD tools, Wavionix etc.) or has ICAO now moved into the area of Pans-Ops software development? Is this the beginning of an entire Pans-Ops software development or section of ICAO?

5. The software will be documented in "Document CD-101". The CRM software was open source material and fully documented in the "Use of the CRM". Will this new software that ICAO is distributing to states be as open? Maybe not to the extent of documenting the software source code but at least documenting the formulas and programming procedures followed in both the software for OAS constants and the OCH calculations.

Naming of objects in the commercial world is a very powerful marketing tool as I saw during my unfortunate time with Wavionix. Why is this CD-ROM to be called the "PANS-OPS OAS CD-ROM"? As I think it will lead onto other Pans-Ops software being included next year and an OCP amendment just dropping the "OAS" in the name. I suggest that this CD-ROM be called what it is "ICAO OAS constants".

Similarly the "Manual on the use of the Collision Risk Model (CRM) for ILS operations" has now changed to,

wait for it.....,

the "PANS-OPS Software" manual. I will await the amendment next year that details the use of the new "ILS basic surfaces calculator". Once again I suggest that this manual be called what it is "Background and usage of ICAO software".

I realise that many of the points I have raised were not relevant when the CRM was developed as at that time they were not issues. However times have changed and litigation, liability and commercial interests are important points.

What do you all think? I will post all replies.)