I need some help from the PC-12 experts here. I fly a PC-12 for an air ambulance outfit part time. We have several -9 and -10 aircraft. Recently I was flying in heavy icing and turned the ignition from auto to on (old habit from my caravan days). I got a audible alarm while they were on. I don't normally do this but the icing was strong enough that I wanted the extra ignition source so I left it on while I was exiting the icing. The audible alarm continued for the entire time I had the ignition set to on. This only happens in one aircraft. Anyone have any idea if this is normal?

Also is anyone aware of an issue with masks leaking? We have a pilot who refuses to turn on the O2 as part of the before start checklist. He says the masks in back are known for leaking and to only turn the oxygen switch on when we need to use the masks. Supposedly leaving it on will drain the crew oxygen in a matter of minutes if one of the masks in back are leaking.

Ignition on is a good idea in heavy icing.

The chime with the ignitions is NOT normal.

Leaking masks need to be replaced.
The oxygen NEEDS to be on. If there is a fire, you don't have time to be screwing with the oxygen switch.

This reply is correct. Write up the discrepancy, mx will replace the the masks after they get sick of filling O2.......

..and let me add to this.
The cowling is a composite, and fire inside the engine compartment WILL make a cacophony of wonderful carcinogens and toxic compounds that will cause permanent damage with a single breath and it will send it directly to you through the environmental system.

Please take this seriously!!!

Know your mask, practice deploying it until you do it in your sleep.
Make sure it ALWAYS works.

Your employer will not have to deal with life time consequences and/or horrible death. You will.

In that situation the mask was not known to be leaking beforehand. It is a guard against it.

I am not the one suggesting this. It was suggested to me. But this would be for a situation where you do not know the mask is leaking to write it up. It is in case that situation happens unknowingly during flight and thus draining all the O2 which at our usual 1700 fill will be empty in 20 minutes or so. I disagree with the practice as does my employer. I always follow the checklist but there is a strong push to stop turning on the O2 when we do our checklist.

LOL, let me tell you about the time I had a fire in the cockpit with smoke and fumes, the med crew (mainly the murse) argued with me about putting on the masks. My response, "Ok dumbass, but before you pass out from the fumes, please make sure to put a mask on the patient". He might not have heard me though, I had my mask on

True story. I got reprimanded by the company for telling the med crew to put an O2 mask on during a cockpit fire in a PC-12. I no longer work for the company.

Yikes! That almost sounds as if a line is loose. I’ve had a slow leaker if someone leaves the oxygen on overnight, but nothing that quick. That needs to be addressed.

Section 2 limitations,
"The oxygen system shutoff valve handle in the cockpit must be selected to on prior to engine start and throughout the duration of flight."
It's because of the toxic fumes from melting composites....as stated before.
Arm the O2 or don't fly. Have mx check the fittings from the fill port up to the pilot masks.
FYI, early sn pc12s, the O2 was always on and there wasn't a shutoff handle.

You need a new company.
(obviously after this virus is out of the way)

You must have missed the "I no longer work for the company"

As did a few of you. In the oxygen scenario above at preflight there is no "known" issue with the masks. However in the example above during the flight something breaks and causes the oxygen to freeflow from a mask. The idea behind keeping the oxygen off is to ensure should you have an emergency that requires oxygen, that you will have it.

Apparently this happened and was the result of a leak on one of the cabin passenger masks. When they went to use the masks they found there was no oxygen on board. The suggestion given was to keep the oxygen turned off to avoid this happening. It is a simple flick of the oxygen lever.

I am not condoning the idea and not the one suggesting it. I am just asking for advice from the peanut gallery.