Have logged about 40 hours in the Turbine Duke V2 and all has gone well. Well mostly! On my last three or four flights I have been getting a beep at several-second intervals with the master warning flashing. It is not a horn.  This was not happening to me on a number of previous flights so it has me mystified.  It typically begins when I pass through approx 12,000 ft and continues until I level off, usually somewhere between FL200 and FL250.  It quits when I level off.  

 

I am in the green everywhere and usually climbing at approx 2200 to 2400 FPM at 160 to 170 KIAS. Torque at about 1050 and RPM at 2000.

 

When it happened on the first flight I thought it was a stuck AP annunciation that I was nearing the altitude interim altitude I had set because it had started to level me off before I adjusted the Alt to a higher level.  But that has not been the case on subsequent flights.

 

I also thought it might have to do with cabin pressure, but then why would it stop beeping upon reaching cruise altitude?

 

Any thoughts would be appreciated.

What was Ng?  I had the same thing happen to me.  My Ng was fairly close (but not over) the red line.  I might have chalked it up to an inaccurate gauge...something we, as simmers, don't see enough of.

Ng is close to the line when climbing. But not in the red. Using the torque and RPM mentioned above.  I may have backed off on torque over the most recent flights. Was using 1150. Wouldn't higher torque exacerbate an issue with Ng? Or to correct did you reduce RPM?

I reduced torque.  More and more, I'm going back to flying the aircraft with my eyes on Ng.  Torque is good but it lags so much.

Hmmm...I was going to say cabin pressure, but if memory serves me correctly, that has a pretty clear annunciator light associated with it. Maybe the pressure differential as you climb? What do you set your cabin rate to?

 

 

Hmmm...I was going to say cabin pressure, but if memory serves me correctly, that has a pretty clear annunciator light associated with it. Maybe the pressure differential as you climb? What do you set your cabin rate to?

 

That's a good thought.  In my case, I had engine limit lights so it wasn't the issue I had. 

RPM should be kept constant per phase of flight and adjustments made with torque. Torque does have lag, but with experience I am successful in anticipating the rate of change. TOC is not too difficult as the aircraft needs time to accelerate after leveling off, providing ample time for adjustment of torque. TOD is more difficult.  I have learned to anticipate by reducing torque ahead of the beginning of each phase of descent, and hold off the descent until speed begins to bleed off.  Final descent from FAF is aided by lowering gear and dropping more flaps as the descent begins.

 

I got spoiled by the RW pilots handbook I found online for the C90. It included performance/settings tables at various ranges of OAT at flight level cruise. I am developing one for my Turbine Duke V2 but it is only one table so far, based on my experience over the two weeks since I purchased it. All of that experience has been with cruise from FL180 to FL250 in summer weather, so its all in one small range of OAT so far. When OAT changes with the colder weather more pages will be completed. I got spoiled by the tables in the C90 POH, which has tables at 10°C intervals from -30°C to +30°C.

Hmmm...I was going to say cabin pressure, but if memory serves me correctly, that has a pretty clear annunciator light associated with it. Maybe the pressure differential as you climb? What do you set your cabin rate to?

 

Humm. Where is the annunciatior light (cabin pressure) you are referring to? What I see blinking is the Master Caution light, but the audible is a beep with several seconds interval instead of a horn like would sound for overspeed or stall.  

Right-hand annunciator panel, there are two associated with cabin pressure, "Cabin Alt 10k" and "Cabin Press." Either of those lit up?

Right-hand annunciator panel, there are two associated with cabin pressure, "Cabin Alt 10k" and "Cabin Press." Either of those lit up?

 

This pilot needs to ID them and then watch! Thanks for the tutoring!  My guess is that is the issue as I modified my routine in regard to cabin pressure changes based on a RW tutorial for the PA46, and I may have misinterpreted from that video.