AVCANADA

This was posted in another thread but has been a source of performance issues. Most people do not fully understand this system so be careful who explains it to you. Changing the density controller settings effect the max power available from the engines for take off and max power settings.


Quote:
With few exceptions.
Most importantly, and other 350 drivers can confirm, the ac will not be able to maintain altitude with one engine out, feathered or not. It will on paper, but not in practice. This is because operators will degrade (turn down) the maximum available boost level at max power. They do this for operational reasons to reduce wear and make use of full TBO numbers. If red line boost level is not available at max power, altitude can not be maintained at GW.
All manuals quote "red line power".
What is their "unwritten" standard maintanence procedure here? What are their setting?

Disclaimer: "The following statements are designed to be informational in nature, not speculative as it relates the accident that started this thread"
As an AME and a private (non multi rated) pilot. I have to say that the pa 31-350 is my favourite piston twin. It always amazes me that an aircraft that has been around so long still continues to have some of the same misconception follow it. In reference to the statement made above I can attest to the fact that some maintenace facilities turn down the density controllers on these engines to "save" the engine and or recomend part power take offs. I have always refused to do so or recommend part power take offs and here is why. The TIO 540 J2BD engine is a fine engine. The density controller is designed to "if set correctly" provide 350 HP when the throttle is on the stops props at 2575. on a standard day the manifold MP should read 42". On a non standard day the MP may read higher or lower to achieve 350 hp. Without the charts selecting your own MP for take may mean 300 hp one day 235 the next who knows. Max is 49. How much runway do you need who knows. The worse scenario is when maintenance turns down the dentity controller. Now the power available at the throttle stop will always be less than 350. The types of fields that navajos are capable of operating from can demand all 350 hp from both engines. Worse still in an engine out situation the remaining engine will need to be able to develop all the power it is supposed to. Piper Lycoming and Transport Canada have recommend against these practices but I still see the question here in the forums about part power take offs. If your company recommends part power take offs think again If maintenance has turned down the controllers get them set properly. As an AME I have always tried to give pilots all the tools they need to do the job. It is the pilots job to mange the engines, it is the AMEs job to make sure they get 350 hp to manage.

Fly safe

If you were to read the Piper AFM and/or the Lycoming pilots handbook, there is a statement in there to NEVER do a partial power take-off, EVER. The last bit of throttle movement introduces extra fuel that will provide internal cylinder cooling and prevent detonation. IMHO, if owners and/or operators are dialing down the density controller to "save" the engine to reduce costs, tell them to go buy an Aztec or some other cheap airplane rather than risk the lives of pilots and passengers. From your description, it appears you either have engine problems, indication problems or a wing/flaps/flight control missrigging. Lots of luck, you may need it.