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Robobble

Looking for help with real world Cessna Caravan procedures.

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I have a a bunch of questions about how to properly fly the C208B Caravan, specifically the Carenado for P3D v4. The included documentation is lacking. I get that this isn't a study level aircraft but I plan on streaming flights and I want to have all the procedures down. Thanks in advance if you can answer any of these!

 

What do normal power settings look like? I've been using 1800 ft lbs and 1900 rpm for takeoff power, then once I hit about 1000agl I reduce prop speed to 1800 rpm, maintain 1800 ft lbs and hold airspeed to about 115KIAS, then for cruise I set about 1600-1700 ft lbs and 1700 rpm, usually cruising around 145KIAS. I understand all this varies based on temperature and runway length but is this roughly normal?

 

What is the ignition switch for exactly? What is the difference between on and normal and when are both settings used?

 

What is fuel boost and what is it used for? What is the difference between off, normal, and on? The checklist supplied with the aircraft files says to use ON for engine starting and never mentions it again, even though I've completed entire flights with the switch set to off.

 

With the starter switch, start and off are obvious but what function does motor se?

 

When is low and high idle used? I thought high idle was generally used when entering the runway and then back to low when exiting but I've seen youtube videos of real pilots using high idle right after engine start is complete.

 

As far as autopilot, when I set the altitude first and then set either v/s or speed hold, it will stop the climb or descent at the set altitude but if I change the altitude during climb or descent, it totally disregards the new set altitude and either stops at the original set altitude or just continues the climb/descent past the set point. Is this an issue on Carenado's end or am I doing something wrong? If I set a new altitude the G1000 says ALTS in white letters. If I click on the altitude knob the ALTS goes away but either way it doesn't matter.

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check out www.avialogs.com for real world pilots handbooks.

 

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Posted (edited)
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check out www.avialogs.com for real world pilots handbooks.

This is great thanks!

Edited by Robobble

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Posted (edited)

RW Grand Caravan EX pilot and "Carenado 208B mod'er" here, so I will see if I can help. There's a lot to unpack here but I'll do what I can.

 
19 hours ago, Robobble said:

What do normal power settings look like...

 
What you're doing will work but you can get away with more depending on environmental conditions (that are not fully simulated with Carenado to my knowledge). When setting power in the Caravan or any turbine for that matter, you are limited by either torque (TQE) or temp (ITT). Max TQE is 2397 and the max temp is 850°C (for 5 mins, 825° otherwise). In the sim, you can run up to max TQE in most cases. In real world operations here in Colorado at a field elevation in excess of 5000' MSL I generally don't push the limits - it's easier on the PT6 that way, especially with a cooler ITT . Often, I use 2200 ft lbs. The G1000 in the real aircraft has a TQE reference mark that moves based on environmental conditions but we don't have that in the sim.
 
After takeoff, you can keep the power up observing the TQE and ITT limits. Flaps come up at 95 KIAS and you climb at 110-120 KIAS (I use 120). The cruise checklist is when you bring the prop RPM back if desired, I use 1750 or full forward 1900. This should yield 165+ KIAS for cruise and around 350 lbs per hour (not sure how close to that the Carenado version is).
 
 
19 hours ago, Robobble said:

What is the ignition switch for exactly? What is the difference between on and normal and when are both settings used?

 
Once burning, most turbine engines are self sustaining and don't need continuous ignition. The 208B has two igniters that are fed by 14 fuel nozzles. They provide the spark that lights the atomized fuel in the combustion chamber. NORM arms the igniters so that they operate when the starter switch is placed in the start position. ON provides continuous operation of the igniters. Think of flying through precipitation or anything that could potentially snuff out the flame, or during startup, you'd want to keep the igniters running (that's the clicking sound you hear during a PT6 startup). In the sim, you can keep it in NORM at all times.
 
 
19 hours ago, Robobble said:

What is fuel boost and what is it used for? What is the difference between off, normal, and on? The checklist supplied with the aircraft files says to use ON for engine starting and never mentions it again, even though I've completed entire flights with the switch set to off.

 
We spent a couple of hours on the 208's fuel system during training at FlightSafety but I'll try to distill this down.. hah. 🙂 The Caravan uses what's called motive flow through an injector boost pump that delivers fuel to the engine. Additionally, an auxiliary fuel boost pump is used for times when the motive flow fuel pressure drops below 2.5 psi or when fuel is needed for startup. Placing the fuel boost into the NORM position arms the aux fuel boost pump, ON closes the motive flow and uses the aux fuel pump to provide startup flow to the fuel control unit (FCU). 
 
 
19 hours ago, Robobble said:

With the starter switch, start and off are obvious but what function does motor se?

 
The starter switch MOTOR position will use the battery to turn the engine without combustion being what spins the engine. Among a few other things, this is used for compressor washes or when you have a ground fire and need to "suck" the flames out.
 
 
19 hours ago, Robobble said:

When is low and high idle used? I thought high idle was generally used when entering the runway and then back to low when exiting but I've seen youtube videos of real pilots using high idle right after engine start is complete.  

 
The fuel condition lever tells the FCU how to schedule/deliver fuel to the engine and directly how fast the engine will rotate (Ng). LOW IDLE results in approx 55% Ng and HIGH IDLE results in approx 65% Ng, so there's not a huge difference. The checklist procedure is to go into LOW IDLE after start and for taxi-out, then HIGH IDLE for takeoff and flight, and then back to LOW IDLE after clearing the runway/taxi-in. The logic is that if you taxi in low idle, you'll reduce taxi speed and wear on the brakes (though I just move the power into Beta as needed which results in not much need to use the brakes anyhow - you can do this by pressing F2 once or twice).
 
 
19 hours ago, Robobble said:

As far as autopilot, when I set the altitude first and then set either v/s or speed hold, it will stop the climb or descent at the set altitude but if I change the altitude during climb or descent, it totally disregards the new set altitude and either stops at the original set altitude or just continues the climb/descent past the set point. Is this an issue on Carenado's end or am I doing something wrong? If I set a new altitude the G1000 says ALTS in white letters. If I click on the altitude knob the ALTS goes away but either way it doesn't matter.

 
Sounds like a Carenado gauge programming "Easter Egg" though I've not encountered it myself (I also don't fly the 208 in the sim very much!)... But, white text in the autopilot mode display area of the PFD indicates that it's "armed" and green text means it's captured/active. ALTS in white = altitude select mode, ALT in green is captured.
Edited by V1VrV2
  • Like 1

Trevor Bair

PP ASEL+IR | Cessna Driver: C172 ᛫ C182 ᛫ C208B
My Real World Travels

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3 hours ago, V1VrV2 said:

RW Grand Caravan EX pilot and "Carenado 208B mod'er" here, so I will see if I can help. There's a lot to unpack here but I'll do what I can

Thanks so much, this is exactly what I was looking for!

3 hours ago, V1VrV2 said:

Once burning, most turbine engines are self sustaining and don't need continuous ignition. The 208B has two igniters that are fed by 14 fuel nozzles. They provide the spark that lights the atomized fuel in the combustion chamber. NORM arms the igniters so that they operate when the starter switch is placed in the start position. ON provides continuous operation of the igniters. Think of flying through precipitation or anything that could potentially snuff out the flame, or during startup, you'd want to keep the igniters running (that's the clicking sound you hear during a PT6 startup). In the sim, you can keep it in NORM at all times.

I did some reading in old Cessna manuals that yurei suggested and read the same thing. However in the Carenado, the engine won't start without the ignition switch in the ON position. I guess just another problem with the aircraft.

3 hours ago, V1VrV2 said:

We spent a couple of hours on the 208's fuel system during training at FlightSafety but I'll try to distill this down.. hah. 🙂 The Caravan uses what's called motive flow through an injector boost pump that delivers fuel to the engine. Additionally, an auxiliary fuel boost pump is used for times when the motive flow fuel pressure drops below 2.5 psi or when fuel is needed for startup. Placing the fuel boost into the NORM position arms the aux fuel boost pump, ON closes the motive flow and uses the aux fuel pump to provide startup flow to the fuel control unit (FCU). 

I suspect in the Carenado that this does nothing besides play a fuel pump sound because it doesn't seem to matter what position the switch is in at all. The engine will start perfectly fine with fuel boost off.

 

As far as the rest, noted and thanks a lot. I get that I can get away with a lot in the sim but I'm interested in keeping the procedures true to life for streaming and I'd rather keep it like that anyways, else why would I be simming?

Last night I flew a 1h30min flight for FSE, flew the best hand-flown approach I've ever flown and totally greased the landing in a bit of a crosswind. Seriously epic flight and then the sim crashed as I was exiting the runway. So of course I loaded the flight up again, set the G1000 DCT to my destination, didn't bother with ATC, firewalled the throttle the entire time, and ran the sim at X64 until I was directly over the airport when I nosedived from 10,000 ft, pretty sure I hit 300KIAS there for a minute. Greased it again and completed the same flight in about 5 mins 😄

 

So yes, the sim engine doesn't really care what you do to it unfortunately. I wish there were a more realistic C208 for P3D.

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