[P7_TOM]

I claim moderator Sunday indulgence.  I have lifted the 'Sunfish'  post below from the UP, simply because it seems to me that the questions and construct are valid.  Most of us know SFA about the 'technical' side of the ADS-B rort; only the staggering costs of no option compliance.  Anyway - FWIW - from Sunny:-

ADS-B and Air Traffic Control Systems - a Financial and Operational Disaster?

I will preface this post by a disclaimer: I know SFA about ATC and the finer points of ADS - B, I have however been up to my neck in large expensive complex IT projects.

It started off at Ausfly as an innocent question over a beer to what I assume was a knowledgeable ADS - B person: "Dynon has announced a $US590 ADS -B conforming GPS for the USA, what chance it could be used here instead of a $5000+ certified GPS navigator for ADS - B?".

The answer to that, I was told was "Not a snowballs chance in hell". The discussion then turned to things technical. microseconds, thronomisters, and the like, about how ADS - B works with radar sets interrogation and suchlike.

"Couldn't ADS - B work with a reduced accuracy GPS with the integrity/accuracy bits set to low levels?" I asked innocently.

"Oh No!" chimed in an ATC person. "If we get ADS - B signals that aren't of the required accuracy, then we are going to have to put 25 mile buffers around the source aircraft to ensure separation". I thought I heard him say. According to him, one aircraft transmitting BS ADS - B signals will cuts a swathe through traffic as ATC has no way of knowing exactly where they are if the system relies on ADS - B alone! The discussion then turned to the vagaries of GPS and we all told our horror stories.

I think however I understood his point: if there are any dubious ADS-B returns in the system then the entire separation schemes, fuel cost savings from reduced separations, direct routings, etc., etc. breaks down. ATC can't just exclude an aircraft from its system and carry on as normal, because it can't be sure where that aircraft really is and thus can't guarantee separation. Of course this is a probability argument, it won't happen every time but you understand the drift.

I then thought of Thales and the new air traffic control system. I thought of the comments from knowledgeable people: "biggest crooks unhung". I thought of the recent disclosure in the Senate of apparent conflicts of interest in the project management. I thought of the CEO of AIrservices slightly unusual departure after only one term.

I thought of what I know about how contractors work on complex IT projects - how you bid low and then add on "variations" until the cost is triple the original budget. I thought of how the request for tender documents are always Five years out of date and behind todays technology and the window for profit that opens for the contractor.

Then I started to wonder: What are the chances of Thales delivering an ATC system that relies solely, or almost solely on ADS - B? What are the chances that any cost savings from the new system are reliant on a perfect implementation of ADS - B? Letting my mind wander, I asked what happens if an ADS - B aircraft has equipment failure in flight, or some butter fingered idiot stuffs up the setting on an ADS - B transponder?

Where is the resilience in the new ATC system? Does it rely almost solely on ADS - B? What is the backup? WHere is the redundancy? Is ATC effectively going to be blind if someone stuffs up ADS - B?

If I were a contractor, would I care if the new system was fragile as glass? No. Would I build in backups and resilience? No, those things are at extra cost. I would then generate more revenue and profit, building in the resilience and capacity to cope without ADS - B.

Such were my musings as I froze to death in my sleeping bag at Ausfly. Could I be forgiven for wondering if Australias new Air traffic control is going to be dangerously over reliant on a perfect implementation of a single technology - bearing in mind that no implementation is ever perfect?

Nice one Sunny - here,  have a CF.