PT6 question

[satpak77]

Good advice. I have an approved realistic checklist but the problem is the ramp is too congested and small to do run-up items and the FMS and EFIS takes at least 5 minutes to start; goofy Chelton system.

Beech's checklist reads more like an instruction manual, takes way too long to accomplish, and it has too many redundant items. Their "Before Landing Check" takes so long that after you put the wheels down and finish reading it you're pulling up to the gate.

Yeah it is not fluid or pilot friendly.

 

[wrxpilot]

I personally don't fly out on the SID/etc via FMS NAV, I use old-school VOR radials until the climb-out, and if everything looks cool, I bring the FMS NAV up. I know Generation-Y doesn't do it that way but it is how I do it. I don't fly with an Ipod either....

Anyway, some ideas for you

Why do you not use the FMS for the SID? Not that there's anything wrong with that, I was just curious (always trying to learn something new).

 

[avbug]

When you start a PT6 in feather you put a lot of strain on the starter generator and can run the risk of burning it up, or draining that battery if starting without a GPU.

No, you really don't.

The starter has no idea whether the propeller is feathered or not. The starter is turning the gas generator, NOT the propeller. It's a free turbine engine. Exhausted gasses from the gas generator cause the propeller to turn. The propeller in feather, or out of feather makes no difference to the starter, and a feathered propeller puts no strain on the starter.

One can hold onto the propeller or tie it down,and it won't make any difference to the starter.

This is true on any PT6 installation, and equally true on the Piaggio Avanti as it is on the King Air series.

If the engine is started in ground idle, at approximately 47% Ng the GCU will disengage the starter. If you start in feather the chances of actually reaching that 47% are pretty remote, if not impossible.

Also untrue, as propeller RPM doesn't control Ng RPM during the start process. Again, one can bring the engine online without any movement from the propeller at all (in theory), assuming one can find a means of securing the propeller from movement against the resulting torque.

The gas generator does not require any particular degree of propeller movement or rotation in order to reach a cutout speed or complete the engine start.

Secondly, the oil tank is integral to the accessory gearbox. With no oil traveling to the prop hub you create an unnecessary amount of high pressure build up in the accessory gearbox. That in itself, is another reason why it's not a good idea to sit around in feather for long periods of time.

There is no pressure buildup in the accessory gearbox as a result of operating with the propeller in feather.

 

[satpak77]

Why do you not use the FMS for the SID? Not that there's anything wrong with that, I was just curious (always trying to learn something new).

I fly out of some mountainous areas, at many non-home-base-airports, with a variety of King Airs, and have found that the chance to misprogram the box is greater than if I flew the same bird everyday, out of the same airport, everyday.

Flying a departure at night via FMS, in mountainous terrain, can bite you if the SID doesn't load correctly or they give you a new SID as you taxi to the Hold Short line (South America SOP).

At the end of the day, it works for me.

 

[wrxpilot]

I fly out of some mountainous areas, at many non-home-base-airports, with a variety of King Airs, and have found that the chance to misprogram the box is greater than if I flew the same bird everyday, out of the same airport, everyday.

Flying a departure at night via FMS, in mountainous terrain, can bite you if the SID doesn't load correctly or they give you a new SID as you taxi to the Hold Short line (South America SOP).

At the end of the day, it works for me.

Makes sense to me, thanks.

 

[satpak77]

Makes sense to me, thanks.

No problem amigo

 

[skydivinguy]

A&PMECH, you're new at this right???

"The topic starter asked about how it would harm the compressor section and I don't see any reason why the compressor would be affected. I can see ITT spikes due to the free turbine rotating at a lesser speeds than the power turbine, which can cause poor exhaust scavenging. I have never seen that personally though. "

The free turbine, power turbine is one and the same. Other one is the compressor turbine which of course turns the gas generator.

Doesn't matter where the condition lever is for start or after start as others have pointed out here.

I've held the prop still while the engine was started a couple times, no big deal unless you move the prop, then get out of the way fast!

 

[avbug]

The theory is that one can hold onto the propeller, but even in feather, even at idle, there's significant torque acting on that prop. I've seen people tossed, trying to hang on, and I've seen eyebolts ripped out of cowlings on several occasions when propeller tethers weren't removed prior to the engine start.

 

[CUBMAN]

Starting the 350 the prop levers are forward. As soon as the engine starts turning the oil pressure is building, no problems here. Maybe too much torque but I doubt it. In no time at all the prop is out of feather. On the 1900 there was a limit as to how long the prop could be in feather on the ground due to heating the windows. The Bandierante was the same. I heard a guy say he melted 350 windows because he was sitting still at idle too long. I dont see any problems with the compressor and props in feather. I have held the prop while engine was turning and no ignition for compressor wash. Not a comfortable feeling, just dont let go.

 

[pilothouston123]

Ground ops in feather are bad for: prop blade erosion, engine cooling, FOD ingestion. They are allowed for GPU starting. I just got off the phone with Mr Beech.