FSX Acceleration explained: aircraft, missions, SP2 differences, who needs it, correct boxed installation order and what Steam Edition includes.
FSX Acceleration is Microsoft’s official expansion pack for boxed Microsoft Flight Simulator X. It adds the F/A-18A Hornet, EH-101 and P-51D Mustang, new missions and carrier, sling-load and racing features, while bringing FSX to Service Pack 2 level. It is optional unless an add-on explicitly requires it; Steam Edition already includes it.
What does Microsoft Flight Simulator X: Acceleration add?
Acceleration is both a content expansion and a major platform update for boxed FSX Standard or Deluxe. It is not a standalone simulator, and installing it over Standard does not add the separate Deluxe-edition aircraft or SDK.
- Three aircraft: the F/A-18A Hornet, EH-101 helicopter and P-51D Mustang.
- Missions and activities involving moving aircraft carriers, catapult launches, arrested landings, helicopter sling loads and air racing.
- Updated simulator code, interfaces and fixes associated with the Service Pack 2 generation of FSX.
- The legacy
DX10 Previewrendering option. This can change lighting and visual effects, but older aircraft and scenery may show missing textures or other compatibility problems when it is enabled.
Some add-ons depend on Acceleration-specific gauges, aircraft files, carrier objects or simulator interfaces, which is why their documentation may state Acceleration required.
The expansion also promoted online racing and multiplayer through GameSpy. That matchmaking service no longer operates, but the aircraft, missions, carrier functions, offline activities and add-on components remain usable.
Do you need the FSX Acceleration pack?
You need Acceleration only when you want its content or an add-on explicitly depends on it; the correct choice otherwise depends on your FSX edition.
If the wording on your packaging is unclear, our comparison of boxed, Gold and Steam FSX editions identifies what each release contains.
| FSX installation | Do you need Acceleration? | What to do |
|---|---|---|
| Boxed FSX Standard or Deluxe | Optional | Install it for the extra aircraft and missions, or when an add-on specifically requires Acceleration. |
| Boxed FSX with standalone SP2 | Not for basic SP2 updates | Keep SP2 if every add-on accepts FSX SP2/Acceleration. SP2 alone does not provide the expansion aircraft, missions or Acceleration-only files. |
| FSX Gold Edition | Already supplied | Gold includes Deluxe plus a separate Acceleration disc. The expansion still has to be installed after the main simulator. |
| FSX: Steam Edition | No | Steam Edition already contains the Acceleration aircraft, missions, features and updated simulator code. |
Never install the boxed Acceleration expansion over FSX: Steam Edition. It is unnecessary, and the old installer may target boxed-FSX folders or registry entries rather than the Steam installation. We explain exactly what Steam Edition inherits from Acceleration and the few packaging differences that remain.
Is FSX Acceleration the same as Service Pack 2?
No. Acceleration includes SP2-era simulator updates, but the standalone FSX Service Pack 2 does not include the Acceleration expansion content.
| Component | Standalone FSX SP2 | FSX Acceleration |
|---|---|---|
| Core SP2 fixes and interfaces | Yes | Yes |
| F/A-18A, EH-101 and P-51D | No | Yes |
| Carrier, sling-load and racing content | No | Yes |
Usually meets an SP2/Acceleration requirement | Yes | Yes |
Meets an explicit Acceleration required notice | No | Yes |
Do not install standalone SP2 after Acceleration. The expansion has already applied its later simulator code, and layering the separate service pack over it can damage or confuse the installation.
What does “SP2/Acceleration required” mean for an add-on?
An add-on labelled FSX SP2/Acceleration normally needs interfaces present in either updated platform. One labelled only Acceleration required may depend on expansion-specific aircraft, gauges, carrier functions or other files that standalone SP2 does not contain.
FSX: Steam Edition normally satisfies both requirements. Older installers may still fail because they search for the boxed edition’s path or registry information; that is an installer-detection problem, not proof that Acceleration is missing. Our guide to FSX add-on compatibility with Steam Edition covers those path and installer limitations.
Copying a few Acceleration gauges or aircraft files into an SP2 installation is not a supported substitute. Dependencies can be spread across several simulator folders, and the expansion remains licensed software.
Can you download FSX Acceleration?
FSX Acceleration is a licensed commercial expansion, not a free service pack or freeware download. The free update commonly confused with it is standalone FSX Service Pack 2, which supplies platform fixes but none of the expansion aircraft or missions.
Owners of the boxed expansion should install it from their licensed media. For a digital FSX installation, Steam Edition already incorporates the Acceleration content, so a separate Flight Simulator X Acceleration download or boxed installer is neither required nor appropriate.
How should you install FSX Acceleration on boxed FSX?
The clean boxed installation order is the base simulator, one successful launch, and then Acceleration; standalone SP2 must not be installed on top afterwards.
- Confirm the edition. Use the Acceleration installer only with boxed FSX Standard or Deluxe, including the Deluxe installation supplied with Gold Edition. Do not use it with Steam Edition.
- Install and launch boxed FSX. Complete the base installation and any licence prompts, then run the simulator once so it creates its configuration data and records the installation correctly.
- Check the service-pack state. Acceleration brings FSX to its own SP2-era level. SP1 can remain if already installed, but a separately installed SP2 may have to be removed through Windows’ installed-apps control panel before Acceleration setup will continue.
- Install Acceleration into the detected FSX installation. It must extend the same simulator and cannot be maintained as an independent copy on another drive. If boxed FSX is already on another drive, Acceleration should follow that installation.
- Launch FSX and verify the aircraft. Complete any expansion licence prompt, close the simulator normally, and only then begin installing third-party aircraft or scenery.
For modern versions of Windows, follow our boxed Acceleration installation sequence and modern-PC precautions, particularly if SP2 or old add-ons are already present.
A setup message claiming that FSX cannot be found usually points to the wrong edition, a missing boxed-FSX registry entry, or a simulator folder that was moved manually. Repair the boxed base installation and launch it once rather than directing the expansion at Steam Edition. If setup reports that a later service pack is present, remove standalone SP2 instead of deleting simulator files by hand.
How can you tell whether FSX Acceleration is installed?
The quickest check is the FSX aircraft selection screen: the default F/A-18A Hornet, EH-101 and P-51D Mustang indicate that the Acceleration content is present.
Clear any manufacturer, publisher or aircraft-type filters before deciding that the aircraft are missing. Steam Edition includes them by design; boxed FSX with standalone SP2 alone does not. Acceleration missions involving carrier operations, sling loads and racing provide a second check.
Is FSX Acceleration the same as time acceleration?
No. The Acceleration expansion pack adds aircraft, missions and simulator updates, while time acceleration changes the simulation rate so a flight passes more quickly. Simulation-rate controls are available without buying the expansion, so a search for “flight simulator acceleration” may refer to two unrelated features.