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Say an aircraft takes off of a carrier to do a mission somewhere, and upon returning to the carrier the pilot comes to find that a thick layer of fog has formed just above the surface of the water in addition to low-level clouds. The pilot may have the ship's exact location, but is it still possible to land?

In the civilian world, usually IFR minimums are 200 ft. AGL, but I am assuming this doesn't apply to military aircraft out at sea, mostly because the ocean is usually a flat surface at a known altitude, (0 ft. MSL), and therefore the risks of terrain other than the surface of the ocean would not be a factor. I also assume they don't apply to carrier-aircraft because, well, they're the military.

However, if the ship is completely shrouded by weather, what would the pilot do? Are there instruments/procedures used to execute a super precise spot-landing with virtually no visibility? What if the plane is bingo fuel?

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    $\begingroup$ en.wikipedia.org/wiki/… $\endgroup$ – expeditedescent Aug 9 at 6:25
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    $\begingroup$ Carriers often(?) operate as part of a fleet of other ships, although their heights are pretty low. $\endgroup$ – Peter Cordes Aug 10 at 0:24
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    $\begingroup$ One big advantage of a carrier over normal airports is that the average airport can't just move 20 kilometer to a less cloudy spot. $\endgroup$ – MSalters Aug 10 at 7:04
  • $\begingroup$ When both the aircraft and airport are correctly equipped, even airliners can land in thick fog. See ILS, especially CAT III, and Autoland. Without that some major airports like CDG would be closed a bit too often! $\endgroup$ – jcaron Aug 10 at 12:43
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    $\begingroup$ Improvise. forces.net/services/tri-service/… $\endgroup$ – Brian Drummond Aug 10 at 12:58
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My experience is circa 1990s, but I can offer some perspective on US fixed wing operations.

Besides TACAN and ASR for non-precision approaches, there are (were) 3 precision instrument approach options available: Precision Approach Radar (PAR), Instrument Landing System (ILS, or “Bullseye”) Automatic Carrier Landing System (ACLS).

PAR: This consists of both azimuth and glide slope radar that allows the controller to issue verbal advisories to “talk down” the pilot. This is generally a back up for when the other systems might not be working.

ILS: Although it works on different frequencies than civilian ILS, functionally it is identical. A passive signal is received by the approaching aircraft which powers azimuth and glide slope indicators in the cockpit.

ACLS: This is an active system that locks onto the aircraft and sends a discrete signal to drive the indicators. For a pilot flying a Mode 2 approach the indications are identical to the ILS, but there is greater precision as well as the option to upgrade to a Mode 1. In a Mode 1 ACLS approach the pilot can couple the autopilot to the signal to allow it to fly the approach hands-off.

All these options are similar to what civil airfields have available, with one notable exception: The aircraft carrier has Landing Signal Officers (LSOs) on station. These hardy souls man the flight deck during all recovery operations, in all kinds of weather, and are the final piece in helping a pilot get aboard when the weather is bad. In very poor visibility LSOs can see the landing light before the pilot can see the carrier and can help talk them down on short final. (There are lots videos on YouTube of this...)

Because of the unique functionality of the Pilot/LSO team, the concept of “minimums” and “missed approach” don’t really apply at the ship. At 3/4 mile from touchdown the pilot will be asked by the controller to “call the ball” in reference to seeing the glide slope indicator of the ship’s Optical Landing System. The pilot will either call the ball in sight, or declare “Clara” which means he/she does not have the ball (ship) in sight. On the call of Clara the LSO will take over issuing power and line up calls over the radio until touchdown, or instruct the pilot to wave off if a safe landing is not possible.

And finally, if the airplane is bingo fuel they would be expected to divert unless the ship is operating blue water, in which case they would go to the tanker.

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    $\begingroup$ Wait, are you saying there's always a tanker circling overhead? Or is that just when the weather's bad? $\endgroup$ – TonyK Aug 9 at 21:58
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    $\begingroup$ @TonyK, Yes, every recovery. But it isn't a jumbo USAF tanker, it is one from the ship. This was a KA-6 Intruder back in the day, an S-3 Viking with buddy store in my time, and I guess F/A-18s are tanking each other now. If weather was bad they might launch the alert tanker to have extra gas airborne. $\endgroup$ – Michael Hall Aug 9 at 22:13
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    $\begingroup$ P.S. The duty tanker pilots were trained so that if they were told by the boss to "hawk" a particular plane, (VFR only) they would be at 1500' up the right side of the ship with their hose out just as it touched down so that if the low-fuel pilot missed catching a wire they could simply raise their landing gear, join up, and start taking gas in under a minute. This was practiced regularly during predeployment workups and was a sight to behold. $\endgroup$ – Michael Hall Aug 9 at 22:20
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    $\begingroup$ Fascinating stuff! What was your role? $\endgroup$ – TonyK Aug 9 at 22:25
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    $\begingroup$ EA-6B Prowler pilot and LSO. $\endgroup$ – Michael Hall Aug 9 at 22:35
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Although I can’t detail fixed wing operations at sea, many countries operating helicopters use an ELVA procedure, an Emergency Low Visibility Approach. Most vessels operating aircraft will have a radar to provide a SCA (ship controlled approach) or if the helicopter has a radar it will be able to fly its own HCA (helicopter controlled approach). Assuming the helicopter can’t get visual using these facilities (with approach and deck lighting turned up full etc) an ELVA would be used. This involves the helicopter approaching the vessel from 180-deg at approx 2nm astern at deck height plus 10-20ft. For a carrier this would be about 60-70ft. The helicopter would normally be using a radalt height hold at this point and would close the ship at a slow speed. The ship would be dropping marker flares into the water from the stern, as the aircraft gets closer the closing speed would be reduced to 10-15kts above the ship speed until visual. Unlike a radar controlled approach, there is no planned go-around for this procedure however, if a land based diversion was available, this would be used first.

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