I HAVE A CTNA THAT HAS MANY BLOOMS ON IT. DURING THE LAST WEEK, A CLEAR STICKY SAP IS EMITTING FROM THE BASE OF EACH FLOWER AND THE FLOWERS ARE STARTING TO FALL OF. IS THIS NORMAL?

This is most likely normal. Many orchids produce sap or honeydew from their flowers or the stems - the only time to be concerned is if aphids are present - look at the back of the flowers and make sure there are no pesky aphids hiding as they can also produce honey dew.

The production of this sap - which is sometimes referred to by a variety of names including: "Happy Sap", "Healthy Honeydew", "Thank You Trickles", as well as other names including orchid honey.

Just some of the names used to identify these beads of nectar produced by the plant as it announces to pollinators that it is getting ready to bloom.

These are sure signs that the plant is healthy and the flower buds are in good shape. Keep them away from ants though, as they tend to flock to the plant to harvest these droplets.

Some folks here are known to lick them (literally) or taste them and say it tastes very sugary. I personally would not though, as some can be hallucinogenic and may contain pesticides or other chemicals

In excess, as in if there are lots of droplets can be a normal condition of change of growing environment - "humidity shock". The plant has been growing in a greenhouse under ideal humidity and then brought outside suddenly.

The vapor pressure difference between the interior and exterior of the plant will cause internal fluids to leak out. This process normally happens through the stomata, but can also happen through the nectar ducts at the base of the flower stalks.

The nectar production is a natural process employed by most orchids to attract pollinators. The reason you do not see them most of the time is that the droplets are very small and dry up quickly to be observed.
Adding humidity shock to the equation, more water is mixed in with the nectar droplets and it makes them bigger (more visible) and takes longer to dry up.

Depending on the plant health, the humidity and other factors, normally your cattleytonia blooms will stay on the plant less than two weeks. If they are lasting less than a week, however, other conditions may be making the blooms fall off or blast. This could be proximity to ripening fruit (which produces ethylene gas) or air pollution from cigarettes, air freshener, smog or even just your gas range/oven.

I hope that helps!

--Scott