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Landfall procedure? - P.Rutherford - 04-14-2016
I've been reading some old Air Force manuals which mention using the Landfall procedure as a safe means to arrive at your destination while flying.
Francis Chichester used it (maybe invented it) and Fred Noonan did also (though for the latter it didn't work out too well).
Can anyone explain it to me as I'm rather confused in how to do it.
Paul
RE: Landfall procedure? - c_davidson - 04-18-2016
Paul,
I'm no expert of even too knowledgeable about the Landfall procedure.
I read Chichester's method a long time ago but remember very little about it. Pretty sure you calculate Hc and Zn for the destination based on your ETA (Estimated Time of Arrival) and then turn 90° to the right or left (depending upon....) run the the azimuth down.
Here's what I found on the web (it's attached in this post).
Maybe that'll help explain Landfall to us all?
Clen
RE: Landfall procedure? - Baendu - 06-02-2016
Hi guys, here is a webpage that has a lot of good info about landfall procedures. The page is focused mainly on Fred Noonan and Amelia Earharts last flight but as stated before, lots on landfalls.
https://sites.google.com/site/fredienoonan/topics/landfall-procedure
To oversimplify the process all you do is travel (fly or sail) purposely to one side of your destination and precompute a LOP over your destination for your ETA. When your sextant tells you that you are on that LOP you then turn towards your destination and head down the line until you arrive. Remember you went off to one side so you know which way the destination is and can turn towards it. This is usually used during the day when the sun is your only body for a sight. If it were nighttime you would just shoot some stars and get a fix. I've only been learning celnav for a month so I'm no expert but I'm pretty sure that's right.
RE: Landfall procedure? - c_davidson - 06-03-2016
Baendu,
In the past I've seen the site you have linked but it's too confusing and disjointed to figure anything out.
Your explanation is a lot easier to understand. Tell me if this is correct; using the Landfall procedure to reach your destination you follow the LOP azimuth that passes through your intended destination making sure you turned the correct direction to it.
You DO NOT follow the azimuth of the celestial body you observed.
Is that right?
Clen
RE: Landfall procedure? - P.Rutherford - 06-03-2016
Fellas, a few weeks back I found this Air Force Landfall training procedure- see below.
[attachment=8]
In its basic form the Landfall procedure is simply following an LOP that passes through your destination once you've reached the point where it does indeed pass through your destination.
Take a look at the navigator on the last page of the document. Looks like a "what, me worry?!" cartoon.
I should have written this up but didn't get around to it.
Paul
RE: Landfall procedure? - Baendu - 06-03-2016
Clen, you are correct, don't worry about the azimith to the body. Once you reach the LOP you want to be on just turn and drive down the azimith of the LOP until you find the destination. I like the page Paul linked to, that's the most complete instruction I've seen. I've been practicing this in the flight sim but have not added wind to mess with my DR yet. It seems to work so far, I fly until the sun is where I want it to be and turn towards my landing strip. It also worked to find an island on my sailboat last weekend but admittedly I was in familiar waters and knew where I was anyway so it wasn't much of a test. Although I think I deserve some credit for taking a sight and reducing it on the deck of a Hobie 14. That was a new experience.
-Dustin
RE: Landfall procedure? - c_davidson - 06-03-2016
Dustin,
That's a pretty good accomplishment- familiar waters or not. A good experience!
These words, "I fly until the sun is where I want it to be..." (understanding you're using a flight simulator) do you mean by that you take a "sight" with a compass (somehow) and then turn? Would you please explain that to me?
Thanks,
Clen
RE: Landfall procedure? - Baendu - 06-03-2016
I have a bubble sextant installed in my plane in the flight sim. (Can be found here http://kronzky.info/fs/sextant/index.html). I do it pretty much the same as you would in real life. A few differences. You have to know the altitude and azimith of the body from your assumed position ahead of time(can't just look out the window and spot a star to shoot). Can be easily looked up on the Naval observatory website. I learned about it (and thenauticalalmanac.com) from this forum thread http://www.flightsim.com/vbfs/showthread.php?230280-Celestial-Navigation-Star-Sun-Positions. I think if I use my Rude star finder and almanac I could calculate the height and azimith ahead of time without using the Naval observatory website but I'm not quite that far yet. The Bubble sextant in game has a sort of
Cheater chart for plotting a fix but I usually do it on paper to get the practice. A lot of fun actually and a good way to learn the concepts behind celnav.
-Dustin
RE: Landfall procedure? - CarlosPindle - 11-11-2016
So then all you do is follow the Sun line (once it is passing through your destination) to the destination?
How do you make sure you're turning toward the destination and not away from it?
RE: Landfall procedure? - pabrides - 06-08-2018
Sounds sort of like the old marine nav procedure of running down a latitude.
RE: Landfall procedure? - LouisC - 06-09-2018
Joe,
It sort of is, but you're following a Sun line azimuth that would pass through your destination.
It's pretty simple.
Lou.