The following are two manuals I've uploaded to the site.
FM 17-47 Air Cavalry Combat Brigade details the employment of the titular unit, the ACCB, and its subordinate Attack Helicopter Battalions and Air Cavalry Squadron. This was an aviation unit meant to be employed by a corps, or placed under the operational control of a division or brigade. Its defining characteristics were high mobility, anti-tank firepower, and competency as a maneuver unit which, as a manual written by the Armor School, was a departure from previous use of attack helicopters as exclusively close air support platforms.
Unlike the more general Attack Helicopter Operations manual, FM 17-47 goes into great detail of the ACCB's employment in operations. Think how the battalions and brigade as a whole fits into corps-sized operations. Both manuals also include chapters on the U.S. Army's assessment of Soviet weapons platforms and unit tactics to be countered.
The ACCB unit concept was initially proposed by the Howze Board on airmobility in 1962, although it was not applied during that decade. It started as an experimental unit under the 1st Cavalry Division during its Triple Capability (TRICAP) phase in the 1970s, and became its own unit (the 6th Cavalry Brigade) in 1975.
I purchased this manual myself to provide the contents for free. If you find it useful and want to support us, you might consider joining our Patreon or making a one-time donation. I'd certainly appreciate it, but it is of course not required.
FM 17-50 Attack Helicopter Operations details the Attack Helicopter Battalion/Company and the tactical application of the AH-1 Cobra. This one is less focused on the ACCB specifically and more about the employment of the helicopters and small units themselves.
I did not purchase this one myself, but I used my paid Scribd account to download it (which can be kind of annoying without an account). I also made the pdf text searchable and gave it a functional linked table of contents.