Oct. 25, 2021: New Update Available - Fully compatibility with SU6

IMPORTANT, READ FIRST
Installation / Mod Package Notes: 

• You must have the deluxe premium edition of MSFS 2020 with the stock Longitude model to use this Mod. This mod is not a stand-alone aircraft. If you install without, you will see game crashes.
• You MUST only install one or the other of the two package folders included - the Standard or the OnAir - NOT both, or you will have conflicts or game crashes. Installation is drag and drop into your Community folder - installation elsewhere will not work. If you don't know how to do this, there are many resources available to show you how to do this.
• After the SU5 update, if you haven't done so already, you must also update the premium and deluxe premium content from the in-game content manager or you will not be able to use the Longitude (and other aircraft) properly.
• With some limited exceptions, this mod doesn't address ANY major avionics modifications to the PFD or MFDs or general cockpit functionality. Unless you can clearly demonstrate otherwise, any bugs or issues with the cockpit functionality are not related to this mod. Please DO NOT inquire about avionics or instruments faults or bugs that you find with WT G3000 or the game's default avionics - I can't help you. These are not the subject of this mod. If installed correctly, the mod is fully compatible with the Working Title G3000 mod package. If you have problems with WT G3000, please inquire with the publishers of that mod - I have no affiliation with them.
• You must have Modern flight model enabled to use this mod. It will not work properly with Legacy flight model settings.
• To confirm correct installation, when in the livery selection menu for the Longitude in MSFS2020, the default Asobo Longitude livery will display the following in the variant area "FDE Fix V1.90" or "FDE Fix V1.90 OnAir" depending on the install version you choose. This will help you quickly identify whether installation of the package was successful and identify package version - this version information will only show up under the default Asobo livery listing and not other liveries, however the performance modifications will be applied to all liveries you have installed.
• The mod does not work with all third party liveries. Some third party liveries are old/out of date and never did or no longer follow proper file structure / installation guidelines and are not compatible. As a result you may see instability or crashes when you do attempt to use these liveries. 
• If your install doesn't work initially, before posting here or on the forum, please close the sim and remove the mod from the community folder. Start the sim and completely reinstall your default Longitude from the Content Manager under your Profile area to ensure you have the latest version. Verify the stock / default Longitude is present and works correctly. Close the sim. Re-download the package here and then re-install the mod as directed (downloads from this site can become corrupted, so that can be a cause of problems with the mod). Restart the sim and verify installation. If this doesn't work, PM me. 

Asobo Cessna Citation Model 700 Longitude Performance and Flight Dynamics Modifications Project Version 1.90a
Featuring Optional OnAir Virtual Airline Compatible Installation Package

Please check out the chatter and follow the progress of this project on the offical MSFS 2020 Forum:
https://forums.flightsimulator.com/t/cessna-citation-longitude-flight-dynamics-modification-project

• Restores aircraft lighting effects omitted from V1.90
• Improved/corrected coefficient of lift settings to reduce unexpected / unrealistic accelerated stall warnings and stall warnings during takeoff and approach / landing.
• Further improvements made to rudder to improve rudder performance in low speed flight.
• Flaps modified to simulate more accurate flaps down stall onset speeds with small improvements to approach performance.
• Incorporated further rudimentary engine overspeed and overheat protections (now it's very difficult to overheat or overspeed the engines).
• Corrected flaps setting indicator in external view HUD to show correct flaps angle for Flaps 2.
• Cabin pressurization altitude corrected to real world settings (5000 feet up to FL400, 5950 at FL450).
• Removed all irrelevant PFD annunciators introduced in SU6.
• Corrected, Modified, or Added annunciators and respective logic flows for the following:
      -Low Fuel caution
      -Fuel Imbalance caution
      -Jet Starter advisory
      -Anti Ice advisory
      -Pitot Heat caution
      -ITT Engine Temp warning
      -N1 Overspeed warning
      -Engine Fire Warning
      -Generator Off caution
      -Battery Off caution
      -Parking brake annunciators
      -Oil Pressure Low annunciators
      -Oil Pressure High caution
      -Oil Temperature Low annunciators
      -Oil Temperature High caution
      -Cabin Pressure caution
      -Cabin Differential Pressure caution
      -Wear Oxygen Mask caution
      -Gear Unsafe Warning

Please see version notes in the included install_readme file for a list of all changes made since project inception and a list of open items / known issues.

Installation:

• Download the .zip file and extract to desktop or other location of choice.
• Install either the standard or OnAir folder in your Community folder (not both)
• Start the sim and enjoy the modded Longitude.
• Please read and follow the installation instructions in the included Install_ReadmeV1.90.txt file carefully.

The Cessna Citation Model 700 Longitude Performance and Flight Dynamics Modifications Project:
After reading user comments on the forums regarding the Cessna Citation Longitude model from Asobo concerning major autopilot problems, inaccurate weights, fuel load, fuel consumption, handling, etc... and due to my own poor experience and frustration with Asobo's starting efforts, I started work on revising a wide variety of parameters in the configuration files borrowed from the Cessna CJ4 model to match the specifications for the Longitude. I modified the default layout.json file for the Longitude to bypass the encrypted configuration files and point to copied versions of non-encrypted files from the CJ4. These files have all been heavily modified and with a fair amount of guesswork I've been able to produce a working version of the Longitude that is more docile in handling and produces performance numbers that much more closely match the real-world specs. I'm not a Longitude pilot, so my modifications are based on comments on forum topics from those who fly the type, and generous contributions of real world C700 aircraft performance charts, flight manuals, and checklists from fellow flight-sim enthusiasts who fly IRL for a living. Input from type-rated pilots with knowledge of the aircraft handling and flight envelope will always be greatly valued.

NOTE: My adjustments are generally focused on performance and handling. Any issues with the G5000 suite and avionics in general are not the subject of this modification (check out the Working Title G3000 modification package for a major upgrade to the default avionics for the Longitude). If Asobo chooses to decrypt the xml files associated with the type, a motivated person could presumably further modify the avionics suite much like has been done with the CJ4 and other un-encrypted aircraft.

I have modified a great many variables and parameters in the available configuration files. I would greatly appreciate feedback on handling, control sensitivies, or other performance related parameters from knowledgable sources so I can continue to improve and update these modifications. If I missed something or you find a performance "glitch" please let me know.

Contribution credit and acknowledgements can be found in the Install_ReadmeVX.XX file included.