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Note: I'm going to work from the AH-64A -10 (TM 1-1520-238-10) which is listed as Distribution A (https://www.abebooks.com/Operators-Manual-Helicopter-Attack-AH-64A-Apache/30838982215/bd); the present document I have is dated August 31, 1994. I understand that the AH-64D likely has many changes from the A model, but this is only as a general reference in an attempt to understand the DCS AH-64D SCAS/SAS/FMC system. Presently, the SCAS/SAS/FMC on the DCS AH-64D provides SAS, CAS, and various active and passive hold modes. For example, heading hold applied at low speeds/hover when pedal and/or force trim release is not pressed. This system is ostensibly to allow for reduced pilot workload throughout the flight regime, given the overall complexity of the aircraft, employing weapons, operating sensors, and the massive array of other potential taskings. However, within the module, the capabilities of the SCAS/SAS seem to be diminished; that is to say, when the FMC functions regarding the various channels are shut off (pitch, roll, yaw, and collective), the aircraft's handling is not noticeably altered. The experiment conducted was a hot start on a pad at Kobuleti airfield, 20C with no wind. An FCR was equipped, 50% fuel, two rocket pods with M274, two empty M299 racks, and an empty gun magazine. The aircraft was taken off into a hover with force trim utilized to stabilize within ground effect. The controls were then released to observe behavior, whereupon the aircraft began to oscillate and pendulum a small amount, then a large amount. Controls were arrested and the aircraft was again pushed into a hover, then the A/C UTIL page was brought up and the FMC YAW, PITCH, ROLL, and COLL channels were commanded off. A stable hover was again commanded, followed by a controls release to observe. As with the test with FMC engaged, the aircraft began to oscillate and more rapidly fall out of control. The aircraft was arrested and then landed. According to the AH-64A -10, the Digital Automatic Stabilization Equipment (DASE) is described as: "The DASE augments stability and enhances maneuverability of the helicopter. DASE includes and/ or controls the following: stability and command augmentation in pitch, roll, and yaw; attitude hold; heading hold; hover augmentation; turn coordination; and the BUCS." This is controlled via a panel in the pilot's cockpit with 5 switches and a BUCS test switch. Paragraph C describes "Automatic Stabilization" in the following: Given this information, I have the following questions: - Does shutting off FMC channels in the DCS AH-64D have any present effect beyond disabling various hold modes? That is to say, are there any SAS or CAS operations being performed when the FMC channels are shut off? - Does the SAS attempt to keep the aircraft on a particular heading, bank, or pitch, or does it only act as a damper for various external influences up to a certain percentage? - How much stability should be expected from the SAS outside of any hold modes? ie in level flight, there is no perceptible difference from FMC channels on and FMC channels off. Should any stabilization occur in forward flight by the FMC, or is it strictly in the hover regime? Is it only for commanded holds such as attitude or altitude? Continued: A second experiment was conducted with the Mi-24P module, for lack of a comparable platform within the game. There is of course a marked contrast between the aircraft in a variety of ways, from the weight to design purpose, to capabilities. For our purposes, it is only to contrast a SAS on a somewhat similar helicopter. As with the AH-64D, the yaw, pitch, and roll SAS channels were ensured on in the same environmental conditions, with the exception of the collective/altitude channel. The aircraft was lifted off into a hover and stabilized with the force trim release. Once the controls were released, the aircraft maintained a generally accurate pitch, bank, and heading, while the aircraft slowly drifted in one direction. A correction was applied and the aircraft stabilized, followed by shutting off the pitch, roll, and yaw SAS channels, then the controls were again released. The airframe remains stable for a few seconds, then begins to oscillate and pitch up, followed by a retaking of the controls and stabilizing again. From this experience, the SAS system on the Mi-24 appears intended to keep the aircraft at a commanded heading, bank, and pitch, and of course in various flight regimes. Given this, these are my questions: - The Mi-24 in general seems to be a far more stable gun platform in the game, with a decidedly powerful SAS that keeps the aircraft well in constraints requested by the crew. Is the more unstable SAS of the AH-64D intended to open up more maneuverability than the more rigid one on the Mi-24? - As with the AH-64D, does shutting off all the SAS channels remove all damping and potentially CAS? A control test was done with the UH-1H, which while lacking a true SAS, does have at least some damping and resistance thanks to the control bar (as intended). The UH-1H, when performing a similar test as with the AH-64D, does not exhibit the same violent oscillations, though it obviously eventually will oscillate out of control. This was merely done to have an aircraft tested in a similar state as the previous two while lacking the same control system. An attempt was made with the SA342L module, but there are idiosyncrasies with the track that prevent it from working as desired. Final notes: This is not to establish whether or not the DCS AH-64D's FM, SAS, and/or SCAS are flawed, inaccurate, improper, or poorly modeled; this is to better understand the underlying aircraft design and intent, so as to properly convey what needs to be learned and taught with the module itself. Tracks have been attached for review per the above testing. Mi-24P SAS vs NO SAS.trkAH-64D FMC vs NO FMC.trkUH-1H CONTROL.trk