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Sky Dolly

Sky Dolly records and replays your flights. The flight data ("simulation variables") is automatically persisted in a logbook which allows you to sort and filter your recorded flights. Various import and export formats such as GPX, KML, JSON or IGC ("international gliding organisation") are supported....


Sky Dolly - The Black Sheep for your Flight Recordings


Sky Dolly is an external, stand-alone application that let's you record and replay your flights in Microsoft Flight Simulator (MSFS). It can also simultaneously replay previously recorded aircraft during recording, making it in effect possible to "iteratively record your own formation flights".

Recording supports multiple sample rates, from 1 Hz up to "auto" ("as data becomes available"). In any case the aicraft position data is interpolated (with cubic Hermite splines), resulting in a smooth flight path.

Recording and replay is done by storing so-called simulation variables that represent the aircraft state. Sky Dolly connects with the flight simulator via the SimConnect API, a standard API introduced with FSX back in the days.


A plugin-based architecture makes Sky Dolly extendable with new functionality, while at the same time reducing the memory footprint (RAM) to a minimum. The following plugins - or modules - are currently available:

  • Logbook - all your flights are automatically stored in the logbook and can be loaded with a single mouse-click. In fact, the underlying storage is an SQL database (SQLite), making powerful filter queries possible
  • Formation - this module let's you control your aircraft in the formation, set relative positions to each other, or simply join interactively an existing formation flight. Recordings with over 30 aircraft didn't slow down the simulation in any noticeable way (*)
  • Location - the location module let's you quickly teleport to the selected location. Besides the position you also get control over the engine state (start, shutdown, keep), making it possible to define your own custom take-off points (for instance custom helipads). Sky Dolly comes with 100 system locations, all finetuned and with verified GPS coordinates. You can easily capture or add your own user locations, e.g. paste any GPS coordinate with CTRL + V into the location table

(*) See known "aircraft jitter" issue below

Import & Export Plugins

Various file formats can be imported or exported:

Flight data:

  • CSV (import & export, including formats from flightradar24.com and Flight Recorder and a simple "position & attitude" format)
  • IGC (International Gliding Commission - import & export)
  • KLM (import for flightaware.com, flightradar24.com and generic KML, Google Earth export)
  • GPX (import and export of the GPS exchange format)
  • JSON (GeoJSON export)


  • CSV (import & export, including Sky Dolly and Little Navmap formats)

For instance you can literally import all world update POIs and airports and more from e.g. here: Little Navmap - MSFS POI Database (made available by Rysatko here on flightsim.to).

Preview Release

Note that this is an early pre-release version 0.14. While it should run stable and all its present features should work as intended it is far from feature complete.

Database Backup and Optimisation

Database backups can be automatically scheduled (once per month, once per week, never, ...) and are done after exiting the Sky Dolly application (where they may also be skipped). Before migration an update is also done. All backup options are now in the File | Logbook Settings... dialog.

By default the backup databases will be located in the same folder as the original "logbook", in a "Backups" subfolder, but can be changed when the Backup dialog shows up.

As flights are recorded and deleted the database file may grow considerably. Unused file space will be reclaimed at some point (by SQLite), but in case many flights have been deleted the database file can be optimised, by the "Optimise" command located in the File menu.

Earlier Releases

In case you want to still use the previous Sky Dolly versions (e.g. 0.12 or 0.13) you may download all previous releases from the github release page (the ZIP archives are identical to the one available here).

Source Code

The source code may be found at:


Additional usage information (README) and a complete CHANGELOG is also available in the github.com source repository. You may want to compute the SHA-256 checksum of your downloaded ZIP archive and compare it against the SHA-256 checksums published on github.com, to verify the file integrity of your downloaded copy.

Reporting Problems

Problems can be reported here:


A free github.com account is required though. "Small issues" may also be mentioned in the comment section below.


  • Unzip the ZIP archive to any location of your choice
  • Run SkyDolly.exe
  • Optional: you may associate Sky Dolly "logbooks" (files with the extension *.sdlog) with the Sky Dolly application:
    • in File Explorer: right-click on the logbook file and choose "Open with..."
    • Select the SkyDolly.exe application
    • Make sure to enable the "Always open with..." checkbox
    • The default logbook is located at: "c:\Users\[Your Username]\Documents\Sky Dolly\"
    • One the *.sdlog files are "associated" with Sky Dolly you can double-click on those files and a new Sky Dolly instance will start and open the selected logbook

Basic Usage

  • Start a flight in Flight Simulator 2020
  • In Sky Dolly, press the "Record" (key R) button
  • Stop the recording (either hit key R again, or ESC for "stop")
  • Press the "Play" button (spacebar)
  • Seek the play position (left and right arrow keys, page up/page down keys)
  • Adjust recording sample rates in the settings menu (also during recording)
  • Show flight information (key F)
    • Hint: press the same key F again to close the flight information dialog
  • Show the recorded "simulation variables" (key V)
    • Same here: press key V again to close the simulation variables dialog
  • Minimise the user interface (key M)
    • Hint: Before you minimise the user interface you may also want to hide the replay speed group, in the View menu
    • As the "minimal UI" as a "fixed layout" the replay speed group currently cannot be shown/hidden once in this "minimal UI" mode
  • Switch between the various modules with the function keys (F1, F2, F3, ...).
Load a Flight
  • Select the desired flight in the logbook
  • Press the "Load" button (or double-click the row)
  • Note: double-clicking its "Title" column will edit the title
Add Aircraft to Existing Flight ("Formation Flying")
  • Switch to the Formation module (press F2)
  • For each aircraft to be recorded press the "Record" button (press R): the plus (+) sign in the button icon indicates that aircraft will be added to the existing flight
  • That's it!

Note again that the existing aircraft will be replayed during recording, so you know exactly where to fly ;)

  • To start a new flight simply switch back to the Logbook module (press F1) and press the record button

You may optionally load an existing flight in the Logbook module before switching to the Formation module. Once all aircraft have been added start replay, pause and seek in the timeline as usual.

  • Aircraft may be deleted from a flight (but which keeps at least one aircraft)
  • The last recorded aircraft becomes the "user aircraft" (the one being followed with the camera in MSFS)
  • Before adding a new aircraft you may set its position relative to the current "user aircraft"
  • You may switch the "user aircraft" at any time - also during replay!
  • Want to fly for yourself together with the formation? Simply select the "Take control" option in order to take control of the recorded user aircraft. Or choose the "Fly with Formation" to join the formation with the currently loaded user aircraft (so you can also join "single aircraft formations" in an ad-hoc manner).
  • Disable "crash detection" and "engine/stress failure" options in Flight Simulator 2020 for replay

Known Issues

  • While the current Sky Dolly v0.14 improves support for 3rd-party aircraft there are still known issues, for example:
    • Spoiler handle position is not properly reported (during recording) and hence cannot properly replayed
    • Some light switches do have "dependencies" between each other, hence single switches cannot easily be toggled alone (or at all)
    • Some simulation variables such as the flaps handle position are updated "in real-time" (e.g. PDMG 737) and hence may temporarily get "out of sync" when seeking quickly back and forth - with repeated seek operations - on the timeline; however during replay those handles should settle again at some point (with the next change event)
  • The stock helicopters from the "40th anniversary update" are not yet fully supported: while position replay works fine, not all flight controls (handles) are fully recorded. Most importantly, both stock helicopters fail to be created when trying to instantiate them as AI aircraft (server exception 22 = "create object failed"), making them "invisible" in formation flights
    • Asobo has confirmed that "helicopter traffic" is not yet supported by MSFS: this implies that helicopter models (as of the "40th anniversary update") cannot be spawned as AI aircraft either
  • Aircraft in formation flights - so-called AI aircraft - tend to "jitter" when flying nearby. This also seems to be related to the speed at which the aircraft fly ("the faster the more jittery"). On the other hand the number of aircraft in the formation does not seem to have an impact (the "jitter" effect already appears with 2 aircraft in the formation).
    • I do have some ideas how to improve on this, but can only tell once implemented whether my idea will be succesful. In either case I will let you know in which release I succeeded or failed.
  • Flights imported from flightaware.com (KML) or flightradar24.com (CSV, KML) often have altitudes not aligned with the MSFS scenery, so aircraft either are below or above the runway when taking off or landing. This is still an open issue and not yet addressed by the most recent v0.14.0 release, but it will be addressed together with extended "flight augmentation" in an upcoming release ("still on the roadmap")
  • In general while error handling of mal-formed imort files is in place the actual error messages are extremly "generic": "File could not be imported". More detailed error messages may be added in a future update, but for now:
    • Make sure that you have selected the proper "flavour" (data source) for a given format
    • For instance depending on whether a KML file comes from flightaware.com or flightradar24.com the position data is stored in different "KML elements"
    • The generic KML format tries to find a "track" element, but if no such track element is present then the same generic "File could not be imported" error message will be shown (for now)
    • In general: if no "position data" (latitude, longitude, optionally altitude) could be found the generic error message will be shown (and also if a "parser error" due to a malformed document is encountered, e.g. an expected number is not in the expected format etc.)
replay recorder flightpath kml igc csv logbook gpx geojson location
Sim Update 11
Първоначална версия
February 28, 2021
Последна актуализация
2 day(s) ago — 0.15.0



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  • Актуализиран до версия 0.15.0

  • Актуализиран до версия 0.14.0

  • Актуализиран до версия 0.13.1

  • Актуализиран до версия 0.13.0

  • Актуализиран до версия 0.12.0

  • Актуализиран до версия 0.11.1

  • Initial File Release

Въз основа на 73 оценки


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© Steeler - All rights reserved. Всяко повторно качване или разпространение на този файл без предварителното писмено съгласие на автора е забранено. Този Flight Simulator 2020 Mod е създаден от Steeler and shared in Utilities » Applications за Microsoft Flight Simulator.

481 Коментари

User Reviews

4.67/5 - Based on 73 reviews

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9 hour(s) ago / Благодарности от Steeler

You Need A really Good You Tube tutorial. The ones I have seen aren't vary good.



3 day(s) ago / Благодарности от Steeler

A fantastic addon for FS2020, absolutely extends the overall experience. Apologies if the answer to this question is in the documentation or previously asked, is Sky Dolly intended to allow a user to import and replay a flight from another user logbook.

Thanks in advance




4 day(s) ago / Благодарности от Steeler

Incredible little tool! I haven't heard of it until recently and just tried it out. Finally I can take a look at my landings!



9 day(s) ago / Благодарности от Steeler

organized and useful tool. However FBW a320 may randomly turn cold and dark during replays



12 day(s) ago / Благодарности от Steeler

Awesome tool. Will be watching with anticipation the jittery formation fix.

"no valid connection plugin has been found in the plugin directory"....what doin now, pls ?



15 day(s) ago / Благодарности от Steeler

Any progress on the fix for the jitter in formation replay? I seem to have that problem a lot recently.



17 day(s) ago / Благодарности от Steeler

This is great. Is it possible to also record the audio?

Hey I'm having a lot of trouble running SkyDolly.exe. Whenever I hit run it tells me I might harm my PC and even if I bypass it, it gives 5 error codes E.G. ''Error Kwaqk file was not found. try reinstalling the program'' I've tried reinstalling but it wont work. HELP ME PLEASE



23 day(s) ago / Благодарности от Steeler

i love this and i use it all the time! i just have one issue and i dont know whether its sky dolly or the sim that is doing this but as you can see in my vid https://www.youtube.com/watch?v=8PaEvHCYxRU when the aircraft turns left the wings move wrong as if the aircraft is rolling on the opposite side, also the movement is more extreme than it should. So is it the sim? is it sky dolly? or did i do something wrong?

doest play replay as formation with helicopters



29 day(s) ago / Благодарности от Steeler

Thank you Steeler! This is the best add on ever! The formation flight has tripled the value of the sim for me. Asobo should add this to the sim. CHF inbound on my next paycheck.

there is no enigne sound at all only flaps sound

.dll virus flag, and no I will not disable it.



2 month(s) ago / Благодарности от Steeler

This is better than a certain payware replayer that I bought. That one's going in the bin. Sky Dolly is where it's at ! Nice work sir.

Any chance an option could be introduced which allows the user to name the clips?



2 month(s) ago / Благодарности от Steeler

Great, Tx!



2 month(s) ago / Благодарности от Steeler

Just than'ks , your mod is amzing !



2 month(s) ago / Благодарности от Steeler

Any steps forward regarding the Flap, Gear etc. control during replay? you said you were working on an "workaround" 😊



3 month(s) ago / Благодарности от Steeler

Thanks for this excellent application, could I ask where the record files are stored physically? I also wonder how the export works - I could not get this to work.

Тези елементи в момента са в списъка и ще бъдат обработени скоро!
Предложения, грешки и идеи за бъдещето.

  • Version 0.15.0 February 02, 2023

    This release is a no-new-features release. Instead it focuses on upgrading 3rd-party libraries, most importantly the Qt 6 framework.


    - Besides fixing some quirks on Windows 11 the new Qt 6 framework also provides initial support for "dark mode"
    - Dark mode is "work in progress" and hence not yet enabled by default
    - However the following command line options explicitly enable dark mode on Windows, with either the _windows_ (default) or _fusion_ style
    * SkyDolly.exe -platform windows:darkmode=2
    * SkyDolly.exe -platform windows:darkmode=2 -style=fusion
    - In either case Sky Dolly then follows the Windows user settings regarding dark mode
    - Starting or resuming replay will now reset the internal _event state_
    * Some aircraft like the PDMG 737 update the _flaps handle index_ (simulation variable) in "real time", that is the value changes asynchronously (together with the extension or retraction of the flaps)
    * Consecutive timeline seek operations may hence bring the internal Sky Dolly _event state_ out-of-sync
    * With this improvement the state will _eventually_ be in-sync again during replay (upon the next flaps event)

    Bug fixes:

    - "Orphaned create AI object" requests are now properly handled
    - When importing a file (e.g. CSV format) without waypoint information the created waypoints have now guaranteed a unique timestamp
    * Specifically in the case when only one position sample ("parked aircraft") exist
    - Properly restore the default "show replay speed" option (applied when entering minimal UI mode) from the application settings

  • Version 0.14.0 January 29, 2023

    This release focuses on improved 3rd-party aircraft support.


    - Improved replay specifically with 3rd party aircraft: primary and secondary flight controls (ailerons, flaps, spoilers, ...), engine (thrust lever), aircraft handles (gear, wing folding, tailhook, ...) and lights
    - Improved replay for AI aircraft ("formation flight"), specifically animation of ailerons, elevator and rudder
    - Less SimConnect data sent to AI aircraft
    - New location categories, including improved CSV import & export with Little Navmap v2.8.8: Addon, Cabin, Carrier, History, Obstacle, Oil Platform, Settlement
    - When pausing recording the simulation is now also paused ("go and fetch a coffee, Capt'n!")
    - No need to "repeat flaps" in settings anymore due to improved secondary flight controls replay
    - Added new flight information simulation variables (dialog Flight -> Conditions): "surface condition" (normal, wet, icy, snow), "on any runway" and "on parking spot"
    - Increasing the replay speed now also increases the simulation rate (up to a maximum rate of 16x)
    - The simulation rate is a power of 2: 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0 - the nearest simulation rate is chosen, given the current replay speed
    - Note: certain aircraft may reduce or even fix the simulation rate to 1.0 (for instance the Fenix A320)
    - When the 'Add to flight' option is enabled and import fails then no empty (no recorded data) aircraft is left in the formation

    Bug Fixes:

    - Fix "ailerons reversal" (Asobo A320neo, F/A-18 and other aircraft with "PID controllers")
    - Ensure that all "position" and "percent" values as reported by MSFS are clamped to the proper range ([-1.0, 1.0] and [0, 100] respectively)
    - Fix a crash in the Formation module that would occur when trying to delete the last aircraft from the aircraft table

  • Version 0.13.1 December 31, 2022

    This release fixes the following issues:

    - The mixture lever position is now properly initialised from "percent" (instead of "position") values:
    * during "flight augmentation" ("flight augmentation" is applied when importing flights from e.g. flightradar24 or flightaware)
    * during IGC import (when detecting "engine noise" in the IGC data)
    - In the Simulation Variables dialog (and elsewhere) ensure that at least one recorded data sample exist before accessing the "last" entry
    - Prevent access to invalidated data upon application termination when either the Flight, Simulation Variables or Statistics dialog was open before quitting the application (rare race condition)
    - Properly spell "airport" in the location CSV export in Little Navmap format (fix typo)

  • Version 0.13.0 December 03, 2022

    Sky Dolly "Dapper Daher" (v0.13) introduces location import and export plugins.

    New features:

    - Location import and export in CSV format
    - Sky Dolly format
    - Little Navmap user points format


    - Reducing the CSV flight export file size (Sky Dolly format), by rounding the digits to 2 decimal places (coordintes: 6 decimal places)
    - In the location module, user and imported locations can now be updated with the current position in the flight simulator
    - Table automatically scrolls to the newly inserted location
    - New system locations (now 101 in total)
    - Locations can now be filtered with keywords, by country, type (system, user, imported) and category
    - The location count is shown
    - The system locations migration file, located at [Sky Dolly installation directory]/Resources/migr/Locations.csv, is now optional and can be deleted
    - Added default aircraft types from simulation update 11 ("40th anniversary update"), for aircraft selector combobox (flight import)
    - Position data is now interpolated within an "infinite interpolation window", hence mported flight plans (e.g. GPX flight plans from Little Navmap) with "sparse waypoints" are now properly replayed
    - Flight Recorder CSV import now also imports "propeller lever position"
    - The keyword search text line edit widgets now have a "clear text" button
    - Performance improvements and bug fixes

  • Version 0.12.0 July 28, 2022

    This release brings the architecture one huge step closer to the final picture: modules are now also implemented as plugins, reducing the memory (RAM) usage even a bit further. The modules are sorted in topological order, based on their defined dependencies (order).

    New features:

    - A new Location module is introduced, allowing to teleport the aircraft to the selected coordinate
    - The current aircraft location can be captured and edited
    - A set of default Locations (currently non-editable by design) is provided
    - GPS coordinates in various formats (decimals, various DMS notations) can be pasted into the Location module with CTRL + V
    - Various attributes such as country and location type can be defined

    A few bug fixes and improvements are also included, also refer to the full https://github.com/till213/SkyDolly/blob/main/CHANGELOG.md. Sky Dolly now also compiles with the Microsoft Visual Studio 2022 compiler and is code-scanned automatically with the Microsoft C++ Code Analysis Action.

  • Version 0.11.1 May 27, 2022

    This release focuses on "quality of life" improvements, both "under the hood" as well as usability and existing feature improvements:

    - A truly minimal user interface mode, configurable in the settings
    - The Formation module features a new Set relative position option which - when unchecked - allows to keep the aircraft to be recorded at its current location
    - Improved AI object resource management, causing less aircraft flickering when e.g. changing the user aircraft in the Formation module
    - Columns in tables can now be moved
    - Less RAM usage, that is resources are released as soon as e.g. a dialog is closed
    - Additional tooltips, consistent dialog titles, alternating table row colours, confirmation dialogs before and after logbook optimisation
    - Architecture / code refactoring

    The newly introduced GeographicLib (third party, open source) converts between WGS84 reference ellipsoid and EGM2008 geoid altitudes ("undulation"), specifically in:

    - The GPX import/export plugins
    - The IGC import/export plugins

    Note that while especially the IGC format specification requires that GNSS altitudes are in relatin to the WGS84 reference ellipsoid not every IGC format may adhere to this specification. That's why for both the IGC and GPX import the altitude conversion is optional.

    Various bug fixes are also included, mostly of "cosmetic nature", but also usability related issues.

    For the complete changelog also refer to: https://github.com/till213/SkyDolly/blob/main/CHANGELOG.md

Често задавани въпроси

Въпроси? Намерете своето решение тук.

How do I install Sky Dolly?

The preview versions are provided in a simple ZIP archive for the time being. Simply unzip the archive in a folder of your choice and run the executable SkyDolly.exe.

You may want to create a "desktop shortcut": simply right-click on SkyDolly.exe and choose "Create shortcut". Move the shortcut onto your desktop and/or to the Windows start menu.

How do I replay a recorded flight?

Load the Flight

Sky Dolly automatically stores all recorded flights in the logbook (an SQLite database):

* Select a flight by left-clicking on a row in the logbook table

* Click the "Load" button

* Alternatively double-click on a row (except on the Title column which starts editing the Title of the flight)

The flight is now loaded into memory and is ready for replay.


In order for Sky Dolly to be able to send ("replay") the recorded "simulation variables" to Flight Simulator 2020 a flight must be already present.

In Flight Simulator 2020

In order to create a new flight in Flight Simulator 2020 follow the usual steps to start a new flight:

* Choose any location on the world map as either departure or arrival (*)

* Choose an aircraft, preferrably the same as with which the original flight has been recorded (**)

* Click the FLY button

* Optional: choose the desired time of day and wheather

(*) The selected location does not matter: the aircraft will be "teleported" to the proper location upon replay

(**) It is technically possibly to replay the flight with any aircraft. Note though that the exact same flight path will be taken (and wheels may seem to be "stuck" in or "float" above the runway, depending on the original aircraft height). So if you record a flight with a Cessna and replay it with an A320neo the flight will be... interesting ;)

The original aircraft with which the flight was recorded is shown in the logbook table as well in the "Flight" (press key F) dialog, under "Aircraft". That "Flight" dialog also shows the initial weather conditions, for information purposes (only).

In Sky Dolly

Now the previously loaded flight can be replayed with Sky Dolly:

* By clicking the "Play" button in Sky Dolly

* Alternatively hit the spacebar or P key

* Hitting the same key again stops the replay

* The key ESC also stops the replay (just as it also stops the recording)

If you want to load another flight simply follow the inital steps above. No need to restart the existing flight in Flight Simulator 2020. Note though that when changing location it may take a while for Flight Simulator to download / update the new terrain data. Graphical glitches are to be expected in this case.

My aircraft crashes during replay - why?

Most aircraft do not like it when they suddenly drop from 20'000 feet altitude right onto the runway upon time slider changes ;)

So it is highly recommended to disable crash, stress & engine damage in Flight Simulator 2020 prior to replay. This is because forces acting on the aircraft are still simulated during replay - and especially also during replay position seeking with the time slider.

So disable the following options in Flight Simulator 2020:

  • Assistance Options / Failure And Damage / Crash Damage -> Disabled
  • Assistance Options / Failure And Damage / Aircraft Stress Damage -> Disabled
  • Assistance Options / Failure And Damage / Engine Stress Damage -> Disabled


What are those "simulation variables"?


Sky Dolly - like most other third party applications - communicates with Flight Simulator via the official SimConnect application programming interface (API).

That API gives access to the aircraft state in the form of so-called "simulation variables". Examples of such variables are:

* Latitude / longitude / altitude

* Aircraft attitude (bank, pitch, heading)

* Gear / flaps up/down

A complete (long!) list of simulaton variables is available in the official developer documentation:


Supported Simulation Variables

In order to keep the required storage space at a minimum and improve performance by minimising the size of the request message sent to Flight Simulator during replay Sky Dolly primarily focuses on variables having the greatest "visual impact". So if a given lever or button activates a visible surface (flaps, ailerons, but also canopy or a landing hook) an attempt to record that variable is made.

Optimised Messages

During replay the previously recorded simulation variables are sent for each "simulated frame" event. In order to optimise performance (fewer messages = less CPU usage) and especially also storage requirements only those variables which have actually changed are recorded and requested during replay.

This is illustrated in the "Simulation Variables" dialog in Sky Dolly (press key V):

* The tabs represent the "simulation variable groups"

* "Inactive" variables - where the value did not change during a certain amount of time - are rendered as disabled text, indicating that they are currently not sent to Flight Simulator 2020 during replay

Note that Sky Dolly applies a clever "seek & search" algorithm which makes sure that all previously set variables are still applied, regardless of when their value has changed last and regardless of the new timeline position which has just been set. Clever :)

Known Limitations

Not all simulation variables are actually "writeable", that is, external applications such as Sky Dolly cannot modify them. Which is a precondition in order to "replay" a given variable.

In addition, not all aircraft honour those simulation variables. That is specifically true for third party aircraft. This is because some aircraft use their own set of (local) variables (for various reasons).

Other aircraft do react to simulation variable changes, but have their own local variable which "counter-acts" against the simulation variable. As Sky Dolly goes a step further - again in order to save on storage space and optimise performance - and only sends variables if their value actually changes such "counter-action" is a problem, as it "nullifies" the effect of the previously set value.

One such example is the "canopy" which either is always closed or opened again, depending on some switch in the cockpit of the given aircraft. In order to override that switch (in effect the corresponding local variable) Sky Dolly offers a "Repeat Values" setting (under File / Settings...), which - if enabled - always send the simulation variable, also if its value does not change.

Custom Simulation Systems (Third Party Aircraft)

Unfortunately one notable example of a 3rd party aircraft which ignores (or "acts weird upon") the official simulation variables is the A320neo (now renamed to A32NX) by "FlyByWire" (FBW), specifically the development version (at the time of this writing). The current 0.6 stable version should still work fine, but the current development version is implementing more and more "custom systems" which do not react upon (or even properly report) the simulation variables, as own internal "local variables" are used to model the various aircraft systems.

Unfortunately that development is "out  of reach" for Sky Dolly, and one shall see whether support for the official "simulation variables" will be (re-)added in future "stable" versions of the A32NX.

Which recording frequency ("sample rate") should I use?

Recording Frequency

Sky Dolly offers the possibility to select the desired recording frequency, or sample rate:

* File / Settings...

* Open the Recording tab

* Set the desired Record Frequency (default: "Auto")

The default setting "Auto" will automatically adjust the recording frequency to the "simulated frame" events, as reported by Flight Simulator 2020. Or in other words: the aircraft state (-> "simulation variables") is sampled every simulated frame.

So why offer the possibility of recording at rates as low as 1 Hz ("one sample per second")? Because the more samples are taken, the more work Flight Simulator 2020 needs to do (to gather the values and send the response messages via the SimConnect adapter to Sky Dolly) and the bigger the storage requirements get.


In any case Sky Dolly always interpolates between the recorded "sample points" with what is known as "cubic spline interpolation" (e.g. refer to https://en.wikipedia.org/wiki/Spline_interpolation as  a good starting point). "Interpolation" basically makes "educated guesses" about values between "known values" ("samples").

However it is intuitively clear that the less data we sample, the less "details" we can capture. When it comes to flying "less details" mostly affects the accuracy of the recorded flight maneuvres: if we only sample at 1 Hz a barrel roll with an (exagerated) roll rate of, say, 2 Hz (two rotations per second!) cannot possibly recorded in an accurate manner!

On the other and airlines which "mostly fly straight lines" and "slow roation movements" may be perfectly captured with a sample rate of 1 Hz only!

The following video illustrates the usage of three different recording rates and compares the results with the original captured video:



* When in doubt, use the "Auto" setting: this gives the best accuracy in any case (at the expense of required storage space - CPU usage is only marginally affected)

* When "long flights with airliners" are to be recorded lower the recording rate accordinly - even 1 Hz results in good results

* Note that you can dynamically change the recording rate while recording!


How do I manually fly with a formation?

The "Formation" module in Sky Dolly allows you to manually take control of the aircraft and join the formation.

Since Sky Dolly v0.8 there are two "formation replay modes" available, namely:

  • Take control of recorded user aircraft
  • Fly with formation

Both replay modes essentially allow you to manually fly together with the recorded aircraft(s) - the formation. The difference: in the first mode you take control of an already recorded aircraft (the one currently selected as "user aircraft"), whereas in the second "Fly with formation" mode you fly along with your currently "active" (loaded) aircraft. This means that you can also join a "single aircraft" formation (the "Take control" mode on the other hand requires at least two recorded aircraft - otherwise you'll simply fly alone again).

This is how it works in detail:

Take Control of Recorded User Aircraft

  • Load an existing flight (at least two aircraft)
  • Switch to the Formation module (press F2)
  • Select the "Take control of recorded user aircraft" replay mode (combobox bottom right)
  • Select the desired aircraft, by marking it as "User Aircraft" (double-click on the table row, or select the row and press the "Set User Aircraft" button)
  • Press "Play" (key P)

You are now in control of the previously recorded user aircraft.

Note that in this repaly mode you can switch the current "user aircraft" (the "active" aircraft being followed by the camera and being flown with the currently loaded aircraft) at any time, also during replay:

  • Select the aircraft in the table
  • Press the "Set user Aircraft" button
  • Alternatively simply double-click on the aircraft row in the table

Fly with Formation

  • Load an existing flight (at least two aircraft)
  • Switch to the Formation module (press F2)
  • Select the "Fly with formation" replay mode (combobox bottom right)
  • Select the desired user aircraft you wish to fly next to, by marking it as "User Aircraft" (see above)
  • Select the desired starting position, by clicking on one of the aircraft icons in the "Bearing" group box
  • Choose the initial vertical / horizontal distance (which is measured in "multiples of wing spans" of the selected user aircraft
  • Press "Play" (key P)

In both modes you can press the "Pause" button (or key P), which also pauses (technically: "freezes") your own manually flown aircraft. In the "Fly with formation" replay mode you can also re-position your aircraft again while paused, by simply clicking on one of the aircraft icons in the "Bearing" group box again.

Returning to Normal Replay

If you get lost you can simply select the "Formation (normal)" replay mode. This will hand back full control to Sky Dolly, over all recorded aircraft.

Sky Dolly v0.8 allows changing the tail number - but with no visible effect?

Yes, since Sky Dolly v0.8 the tail number of the recorded aircraft can be changed in the Formation module (double-click with the left mouse button on the corresponding table cell to enable edit mode).

However it is correct that this does not yet have a visible impact on the currently loaded flight in FS 2020, for two reasons:

* The tail number of the user aircraft (the one being followed by the camera in FS 2020) does not get updated (unless the flight is restarted in FS 2020)

* "AI aircraft" (in formation flights) show a white empty box instead of the tail number (that is a bug in FS 2020)

But I still decided to make the tail number editable in Sky Dolly, because it may actually work better with future releases of FS 2020.

My aircraft recorded with v0.7 (or earlier) randomly shuts down its engine with v0.8?

Why does the engine shut down?

Sky Dolly v0.8 introduced improved "is the engine running" detection and better "autostart/shutdown" support based on a new "combustion" simulation variable which is now being recorded.

For existing flights recorded with Sky Dolly v0.7 and before this simulation variable is initialised ("migrated") on a "best effort guesstimate", as follows:

  • If the thrust lever is > 0, then the combustion is initialised with 1 ("engine running")
  • If the thrust lever is "fully pulled back" (= 0) then the combustion is initialised with 0 ("engine shutdown")

Of course that implies that the engine - again, for flights recorded with v0.7 and earlier only - is now shutdown whenever the thrust levers are fully pulled back. And started again when the thrust levers are pushed forward again.

For flights recorded with Sky Dolly v0.8 the actual "combustion" value as reported by the flight simulator is recorded.

Note that all engines are started at the same time - including for flights recorded with Sky Dolly v0.8 - as soon as one engine combusts: this is because an "engine autostart" event is sent to flight simulator, which is the equivalent to "CTRL + E".

So while this does not allow a faithful replay of the actual engine startup process (specifically when multiple engines are involved) it should more reliable detect when at least one engine is running. This also works when seeking back and forth in the timeline, so "flying aircraft with dead engines" should now be a thing of the past.

Can I re-enable my engines such that they run constantly during the entire flight?

Yes, but this requires some manual steps which involve "diving into the database" (logbook), using a database browser such as:


  • In Sky Dolly it is recommended to first create a backup of your logbook
    • File | Logbook Settings..., choose "Next time, when exiting Sky Dolly"
  • Close Sky Dolly
    • To execute the backup
    • Also in order such that no other transaction is running on the same database while we are modifying the data in the subsequent steps
  • Launch DB Browser for SQLite
  • Open the logbook
    • Set the file filter to "All files"
    • Logbook location, see Files | Logbook Settings... in Sky Dolly
    • Default location: "c:\Users\[Your Username]\Documents\Sky Dolly\Sky Dolly.sdlog"
      • Your backups will by default be in a "Backups" subfolder in that same location
  • In the "Execute SQL" tab copy and paste the following update statement:
    • This will update the "combustion" value of all four engines to 1 ("combusted" = "running") ...
    • ... for the flight given by :id (this placeholder is to be replaced with an actual flight ID, see below)
update engine
set general_engine_combustion1 = 1,
    general_engine_combustion2 = 1,
    general_engine_combustion3 = 1,
    general_engine_combustion4 = 1
where aircraft_id in
(select a.id
 from aircraft a
 join flight f
 on a.flight_id = f.id
 where f.id = :id
  • IMPORTANT: Before you execute this update statement replace the :id (including the colon) with the actual flight ID, e.g. 73
    • The flight IDs are shown in Sky Dolly, in the column "Flight" of the logbook
  • In order to persist the updated data click the "Write changes" button (top-most toolbar)
    • Or execute a commit;

That is it, the engines should now be constantly running for flight 73.

Flaps, spoilers, ailerons and/or gears are not animated during replay - why?


During replay Sky Dolly merely sends the previously recorded simulation variables back to MSFS (also refer to question "What are those simulation variables"). Those simulation variables represent the state of the aircraft and can be "read" and "written" via the official SimConnect API.

Third-Party Aircraft

However especially some third-party aircraft use their own custom simulation systems, e.g. for the hydraulics. Those custom simulation systems use their own set of variables (so-called "local variables") that are not accessible via the SimConnect API.

Or in other words: the official simulation variables are ignored. While they might or might not represent the actual state during recording they are not taken into account during replay.

The result: flaps or gears etc. do not move. There is nothing that can be done currently by the user.

The following third-party aircraft are known to have limited functionality, including but not limited to:

  • A32NX (FlyByWire)
  • A320 (Fenix)
  • Boeing 737 (PMDG)
  • CRJ (Aerosoft)

I do however have some idea to improve on this situation. Whether that will work sufficiently well (or at all) I can only tell once implemented and tested.

The "40th anniversary" helicopters are invisible in formation flights - why?

There seems to be an issue when trying to create them as "AI object": I get back a "server exception 22" as a result of the corresponding "create AI object" request.

Whether this is something I can / have to fix "client-side" (in Sky Dolly) or whether this is really a SimConnect bug related to helicopters I can't tell just yet.


These add-ons may be required or recommended to use.

Доста празно тук.