As long as there have been landable aircraft carriers in FlightSim, there's been a problem that occurs occasionally where the planes on the carrier appear to sink through the deck and come to rest at sea level, inside the ship. With the recent release of AlphaSim's payware "Big E" CVN-65 model, the problem occurred again. Several of us working on AI traffic for her (Robert Baum [Lightning], Graham Stanley [GrahamS], and Lee Britton [LBritton]) have finally developed a solid fix for it. This fix works for all the carriers we've tried it on.When the problem occurs, the planes don't really sink though the deck. What happens is the ocean rises to match the level of the AFCAD for the carrier's flightdeck, the ship rises by the same amount, and the planes stay at the same height. It seems that this is an adaptive mechanism within FlightSim that makes the height of terrain surrounding an airfield adapt to the height of the airfield, if there's a mismatch between them. This works fine on land, but messes things up on a carrier, where you want the "airfield" (the carrier's flightdeck) to be 70 ft. above the "terrain" (the sea's level).The fix involve creating a special AFCAD file for the aircraft carrier. This AFCAD is a dummy airport that is never used by aircraft, and is made invisible. It's positioned underneath the carrier, at sea level. It's sole purpose is to keep the water level separate from the level of the carrier deck. A second, more convention AFCAD file is used for the carrier deck. This is the one that all the planes land on.The Fix=======Summary: Make a simple AFCAD which is only an airport with one apron taxiway that runs the length of the carrier's flightdeck, down the centre, 800 feet wide, at sea level. Use "Unknown" for the apron material, and place the resulting AFCAD file in a scenery folder that is higher priority (in the Scenery Library) than the carrier.Details:To make the sea-level AFCAD file, use the AFCAD2 program by Lee Swordy.With a user plane that's linked to AFCAD2 by FSUIPC (registered or unregistered), slew to a middle point on the deck of the carrier and create a reference point for your new airport there. Give the airport a 4-letter identifier and a name that is different from all other airports in your system. A good way to do that is match the file naming convention described below.Now fill in the airport attributes of the new airport. To do this, right click on the background, click on Properties, to bring up the Airport Properties screen. Fill in these items:Leave Latitude and Longitude unchanged. They are already set by placing the reference point for the airport.Magnetic Variation should be copied from the AFCAD for the carrier's flightdeck.Elevation: 0 (desired sea level)Airport ID = OFXX ("O" is letter "Oh"; XX = sequence number of carrier)Country = CarrierState/Province = "Blank"City = Ocean Flatten (Carrier Name)Airport Name = Ocean Flatten (Carrier Name)Slew the user's plane in FlightSim to the front end of the carrier and place a "marker" (purple cross) there in AFCAD2.Slew to the back end of the carrier in FlightSim and draw an apron taxiway between the two spots in AFCAD2.Make it "Unknown" for surface, so flightsim will not draw it and it will be invisible.Make it 800 feet wide.Make sure it has no markings or lights.Save the airfield you've just created in an AFCAD file with an appropriate file name (see "Naming Conventions" below).Now place the new AFCAD file in the FlightSim Scenery Library.It MUST be in a higher priority scenery folder than the carrier!Place it in a folder that's different from the one the carrier is in, and use the Scenery Library function in FlightSim to activate the folder. Place it HIGHER in the stack (lower Priority number) than the carrier it applies to. The same folder can be used for all the sea-level AFCAD files of all the carriers in your system, but it must be a different folder from all of the ones that have the carriers in them. See the help file for FlightSim for how to access the Scenery Library. See the manual for AFCAD2 to learn how to create an airfield.Naming Conventions==================These are the naming conventions used for the AlphaSim Big E CVN-65 aircraft carriers.Naming convention for the folder for the sea-level AFCAD files:"Carrier Ocean Flatten Files"Naming convention for the sea-level AFCAD files:Use "OFXX". "O" is the letter "Oh" and XX is a number in sequence,because they can't be the same as another airport and there are no OF airports.Big E's will be OF01 to OF10. "OF" for "Ocean Flatten".Interesting Details===================All our testing has been in FS2004. It will probably work in FS2002, but we haven't tested it. I have no clue about whether this can be used in CFS2 or CFS3.We've found that, with this fix in place, it's no longer necessary to use an extra BGL scenery file with an Area16N flatten command in it. This result is preliminary, but we've found it true in all the cases we've tested.We found a fact about priority of scenery files that may explain some of the strange results we sometimes get in tricky scenery situations. For our fix to work, the sea-level AFCAD has to have higher priority in the Scenery Library than the carrier. We found that putting it in a different folder and giving that folder higher priority works (of course). We also found that we could place it in the same folder, and IF IT WAS NAMED SO IT WAS ALPHABETICALLY BEFORE THE CARRIER FILES, IT HAD HIGHER PROIORITY. (Excuse me for shouting, but I

Well, as someone who has CVN's placed all over the world this iscertainly good news.Now, does this address the problem of flying into the scenery area froma distance and finding the sealevel up at flightdeck level?I'm hoping so. I have two CVN's heading west just outside the GoldenGate and as long as I operate from one CVN to the other, all is well.But if I fly from Alameda NAS out to the CVN's, a distance of only7-8 NM, I'm faced with the sea mount syndrome.Thanks for sharing this information....I can see I'll be busy fora few days creating all my "flatten airports" :) Paul

Paul:>Now, does this address the problem of flying into the scenery area from>a distance and finding the sealevel up at flightdeck level? That's exactly the problem this fixes. Enjoy!Please let us know how it works for you.--LBritton

Since I first posted my notes about "Aircraft Carriers: A Fix For Planes Sinking Through The Deck", I've heard from one of the members of the Offshore Development Group (OGD), which is developing a FlightSim add-on consisting of an impressive array of offshore platforms (oil drilling rigs and such) and a fleet of support vessels and aircraft. He points out that their team has developed this same fix, independently from the guy I worked with. He tells meBillG (FlatIron) had previously used this method, but it's relevance had not been noticed.Alun Heseltine (ODG) & Scott Gridley, (ODG & Freeflow) then, independently from BillG, rediscovered the solution.They, plus George Davison (Golf Hotel Delta), had spent 14 months tracking down the double AFCAD solution.Their team and my team didn't know about each other's work on this - we both came up with the same solution independently. It's a classic case of great minds running in the same gutters. Congratulations, guys!Their thread that talks about this is titled: "Elevated helipads - Resolved, Faults, humps & holes, etc"(cut and paste the pieces - this forum breaks the URL)http://64.34.169.161/cgi-bin/ib3/ikonboard...=ST;f=44;t=4441You might want to read the rest of their ODG forum, too. It's an impressive body of work.--LBritton

Convergent evolution!It also works for helipads:http://forums.avsim.net/user_files/138756.jpg

Convergent Evolution?No Lah! That's proof for intelligent design....lol