The HAC maneuver or “Heading Alignment Circle” (a term I lifted from the king of flight: the STS Orbiter) is a useful maneuver for any aircraft. I don’t know if it has another term for fighter pilots or etc.
I performed this maneuver in my Darkstar flight along the Nile (from Equator to Rhodes took only 1 hour). The video isn’t visually appealing so I’ll include screenshots from the flight. I’m posting this for educational purposes as part of my grander scheme to build an instruction manual and procedures for advanced Darkstar flying, but this maneuver is useful for anyone at any scale.
The STS Orbiter needed approximately a 200 mile diameter circle to execute the HAC maneuver, the Darkstar at about Mach 3.5 needs about a 30 mile diameter circle to execute.
I therefore would expect that the maneuver needs to be about the diameter equal to your standard final approach leg where you perform your final descent.
For those who haven’t flown the sim for Darkstar let me tell you what you’re up against.
- Landing from 220,000 feet (the video starts at the final approach of 75,000 feet).
- Starting approach speed that is supersonic.
- The plane stalls at 180knots.
- You have no autopilot.
Hope you enjoy the screenshots of the Nile flyover and the videos if you’re interested in how to perform the flight’s landing.
Africa is huge
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Why I fly the Darkstar
Just exiting the initial approach from 220,000 feet at 75,000 feet and Mach 6.6
Final approach
Details of the maneuver.
In the Darkstar the most important item to remember is 1,000 feet per 1nm glide slope. This seems to be the sweet spot as long as you can keep your EAS speed at about 200knots. (Easier said than done).
When building the flight plan I assumed from experience that I’d need about a 30nm final approach leg to the runway. Because the NAV system imports your flight plan - I set the last way point to the end of the runway so that my alignment was correct. There’s a wonkiness where the final heading is the center of the airport and not a specific runway. That’s a problem when you need to be critically aligned from 30nm away to nail any landing in Darkstar. It’s less of a problem for conventional aircraft though.
You know you’re aligned with your approach when the final leg’s heading indicator (the pink box) is aligned to the heading of the runway. So choose runways you know the heading of. If you don’t know the heading of the runway you’re approaching, it can be discovered in the NavMap’s info on the airport.
Use rudder to control alignment to the runway once you’re fairly aligned. It seems to be more accurate and less over-correcting than using your bank maneuvers alone.
And know your glide slope for your speed. The Darkstar is fairly consistent in landing at a speed of ~200knots which makes it easy to know. But the A310 or such has a calculated landing speed that can be found in your computer’s “TO/AP” button (Takeoff/Approach).
