Devils Advocate
A person would be arrested if they provided a positive (failed) breath test on a screening device. The expression positive and failed mean the same in general.
The arrest being nessesery to get the person to the Police Station for a evidencial test. There would be no dragging off a plane, unless the person wanted to fight about it.
You will have seen from Flying Lawyer's summary that the proccedure for a Police Officer is broadly similar to the action he would take with a driver. Which means that the first test would be on a screening device, at the place where the Officer is called too. This produces an indication based on a red/amber or green LED, rather than a reading of BAC. Red obviously indicating a blood alcohol concentration above the prescribed limit. I am assuming now that the machines used have not changed, I understand that there are hand held machines that give a read out of the BAC, however that reading wouldn't be the one used to provide evidence in court.
If a positive test, ie one that indicated a BAC above the prescribed limit (failed) the person would then be arrested and taken to a Police Station, where they would provide a speciem of Breath into an Evdiencal Breath Test Machine. The result of that provides the evidence for a court. As someone pointed out on another thread, if the result, in the case of a driver is slightly above then they would be allowed a blood test, however in all the cases I was involved in, that blood test was higher than the breath test reading. I don't know if that would happen under this legislation.
One thing which I don't know about is the LED type screening devices we had when I worked at Heathrow were calibrated for the Road Traffic Act limits. I can only presume they have diffeant ones calibrated for this legislation. The Police Station Machine gives a print out of the result, and gives it no matter what the reading.
You would be charged if the result of the Evidendial BT was above the prescribed limit for the appropriate legislation.
If on the specimen provided at the Police station is below the prescribed limit, then thats the end of the matter the person would be realeased. What he told his employers is then his affair. As for informing the CAA I don't know, I would guess that if the BAC was below the limit then no they wouldn't be told by Police, although they may be by the Persons company.
I can't comment on what it says in your ops manual, thats something for your company.
Hope that clarrifys things.