C404 advanced physics: serious OEI training on the Titan

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C404 advanced physics


1. Why I developed the advanced physics version

I was asked via this forum, via PMs and also by e-mails to provide a modified version of the Alabeo C404 which can be used for serious multi-engine training. It should have accurate type specific performance for both AEO (all engine operative) and OEI (one engine inoperative), the latter for either a windmilling prop at various speeds and for a feathered engine. Feathering should work as realistic as possible.

Thus, I developed an advanced physics version of the Alabeo C404. Since I regularly do fly a C421C in real world and the C404 was available on P3D / FSX before the C421 was available, I made adjustments for mass and balance to be identical to the C421C, registration N100L, I fly. The C421C is very close tot he C404: same engines, basically same systems. The C404 is a C421 with a longer cabin and without pressurization.

The mod shows realistic physics for negative thrust (prop drives engine). This is necessary for OEI training and more realistic idle power simulation.


2. Where to download

The modifications to the “c404.air” and “aircraft.cfg” files,
aircraft data, equipment list, checklist and other documents for C421C, N100L can be found here:


Unfortunately, due to copyrights, I can’t upload the full files and can’t provide the AFM and other copyright protected documents.


3. How to install

To update “c404.air”:
- Copy the original Alabeo C404 to another aircraft folder, e.g. “C404 advanced physics”.
- Use AirEd (freeware) and open the original “c404.air”.
   Open AirEd a second time and open “modifications advanced physics c404.air”.
   Copy the modified tables 511 and 512 to the original .air file
   (right click in modification file -> copy -> right click on original file -> replace from clipboard)

To update “aircraft.cfg”:
Just copy the modifications to the corresponding position in the original file.


4. Legend of modifications

Modifications in aircraft.cfg:
- Basic Empty Mass (actual mass for N100L 5,154 lbs inserted; most C421C are more heavy, ours is on diet)
- correct basic data for engines + props
- engine friction included (necessary for all negative thrust scenarios)
- flaps lift + drag scalar adjusted (split flaps)
- VMO = 151 KIAS; VNE= 240 KIAS

Modifications in c404.air:
- implemented negative thrust scenarios in prop thrust and efficiency curves (tables 511 + 512); adjusted thrust curves for high TAS at high ALT


5. Side effects of modifications:

- more realistic engine starting:
starting the engine needs the throttle to be 2 cm above idle (see checklist) for the first 15 seconds

- if you start the engine and don’t retard the prop to medium RPMs immediately, you will overstress engine and prop. So be careful when doing an air start, you might lose the prop and the aircraft. (In the real aircraft, these effects are less severe, but you have to avoid high RPMs until the engine is warmed up and have to avoid rapid change of RPM.)


6. Additional Notes:

- Basic aircraft data as published by the manufacturer, like range and service ceilings, especially OEI, are based on MTOM.

- The use of high payloads close to MTOM and higher ambient temperatures are making for a more challenging OEI training.

- In the sim, climb power is too low compared to full power (about 65 % instead of 75 %). I have to find a way to adjust that. 

- I have buttons for engine failure under the mixture (see images)

- Seat Position is, like in many Aircraft, higher than as per Default by the sim. For the C421C and me being 5 ft 7 in, that's about 7 clicks arrow up.


Stay sharp!
Enjoy the training!

Best regards,


Edited by AndiKunzi
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For clarification, since I was asked by e-mail:

The masses (weights) of the C404 and the C421s are pretty close, the stations are different. I used the weight of the 421 and... when thinking about it - will have to adjust the wing in the aircraft.cfg. I have that in the (copyright protected) original file, but forget to put it in the modification file. Will do that tomorrow. I hate to be not able to hyperlink the full files, for copyright.

I built the model of a C421C out of the C404, regarding behavior, performance and masses (weights), since the C404 was out long before the C421. That‘s why the C404 was the first advanced physics version. The C404 does fly a little less nervous around the pitch axis, much like my real aircraft. Also, I don‘t like the large sun visor on the sim C421, which I can‘t stow away like in real world. The attitude indictor, HSI, flight director and autopilot are also better, clearer and more similar to real world C421C N100L. However, the C421 has a DME (undortunately working on remote frequency only) as well as pressurization and prop sync.
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This is an interesting development.  After being a little disappointed with the Navajo and a lot disappointed with the Chieftain, I decided to not bother with the Titan, even though it looks nice and would make for a great dual role passenger charter/cargo aircraft.  From what I have read on the forums here at Avsim, the Titan had more problems than I cared to deal with.  Please keep us posted on your work.

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Final Version of the modified aircraft.cfg is available for download now.


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