9D004 Category 9D

Other “software” as follows (see List of Items Controlled).

Category 9: Aerospace and Propulsion

Reasons for control

• NS: National security
• AT: Anti-terrorism

Country chart

List-based license exceptions

Items

1. Items: a. 2D or 3D viscous “software”, validated with wind tunnel or flight test data required for detailed engine flow modelling;
2. b. “Software” for testing aero gas turbine engines, assemblies, “parts” or “components”, having all of the following:
3. b.1. “Specially designed” for testing any of the following:
4. b.1.a. Aero gas turbine engines, assemblies or components, incorporating “technology” specified by 9E003.a, 9E003.h or 9E003.i; or
5. b.1.b. Multi-stage compressors providing either bypass or core flow, specially designed for aero gas turbine engines incorporating “technology” specified by 9E003.a or 9E003.h; and
6. b.2. “Specially designed” for all of the following:
7. b.2.a. Acquisition and processing of data, in real time; and
8. b.2.b. Feedback control of the test article or test conditions (e.g., temperature, pressure, flow rate) while the test is in progress;
9. c. “Software” “specially designed” to control directional solidification or single crystal material growth in equipment specified by 9B001.a or 9B001.c;
10. d. [Reserved]
11. e. “Software” “specially designed” or modified for the operation of items specified by 9A012;
12. f. “Software” “specially designed” to design the internal cooling passages of aero gas turbine engine blades, vanes and “tip shrouds”;
13. g. “Software” having all of the following:
14. g.1. “Specially designed” to predict aero thermal, aeromechanical and combustion conditions in aero gas turbine engines; and
15. g.2. Theoretical modeling predictions of the aero thermal, aeromechanical and combustion conditions, which have been validated with actual turbine engine (experimental or production) performance data.

Related controls

See also 9D104.

Notes

Note: 9D004.b does not specify software for operation of the test facility or operator safety (e.g., overspeed shutdown, fire detection and suppression), or production, repair or maintenance acceptance-testing limited to determining if the item has been properly assembled or repaired.

Source: eCFR, version 2026-08-01, retrieved 2026-08-20T04:04:59+00:00.