From: Columbia SC
This is what I have been able to find.
The full quote of what I posted to StK's query elsewhere was:
Recon planes conducting a "recon mission" engage in a point to point activity. Range therefore does not deteriorate their effectiveness.
Patrol planes (includes float planes and bombers) conducting a "naval search" mission are engaged in an area activity. For them there is a negative corelation between distance and effectiveness. From an efficiency POV, there is very limited value in placing to search out for more than 12 hexes.
Note that aircraft conducting an "ASW mission" (another area activity) the range of the plane is halved.
It does not say that a TF will not be spotted at a distance of more than 12 hexes but rather that beyond that point there is a very definite law of diminishing returns which makes it very inefficient once one takes into account the costs associated with searching.
Also read page 217 of the manual which states that beyond 300 miles (ie 8 hexes) TFs are less likely to be spotted by aircraft conducting a naval search mission.
1. Each plane allocated to naval search is given a 10 degree arc. That arc cannot be made smaller or bigger.
2. Each plane in the same squadron is given its own separate arc. They do not cross over into someone else's arc.
3. If you have more planes searching than 10 degree arcs set, the surplus planes will restart back at the first arc set.
4. The only realistic way to get two aircraft to search the same arc whilst still maintaining a wide search pattern is to have two or more separate squadrons allocated the exact same search arcs.
Although often asked, there is no particularly good consolidated thread which thoroughly deals with naval search/ASW arcs. This thread is probably the best single thread.
One of the problems you will encounter is that there are some very strong advocates for not setting search arcs but they tend to hide the details as to why they can get away with it. Newbies read these no set arcs assertions and just adopt the principle that it works perfectly and obviates the case for setting arcs. From that urban myths are created. As always the devil is in the detail. Particularly when reading my posts, one has to be alert to exactly what I say and the nuances I point out.
1. Setting search arcs does increase micromanagement. Players who are averse to micromanagement or at least want to minimise, tend to be very enthusiastic at the prospect of avoiding this additional work load.
2. There is an automatic 360 degree search arc for up to 4 hexes on all naval search/ASW missions. Set the mission out to 4 hexes, you get 360 degree coverage irrespective of what you do. Set the mission out to 8 hexes, you get 360 coverage up to 4 hexes out. Coverage for hexes 5-8 inclusive depends on what you do. Set the mission out to 12 hexes, you get 360 coverage up to 4 hexes out, with coverage of hexes 5-12 inclusive dependent on your selection.
3. Consider the range of your searching aircraft. For example, Allied float planes are not really going to stretch the auto 360 degree coverage are they. So there is no point in setting naval search arcs for them as the code has already taken care of that plus if you did specifically set such search arcs you would need to reset them every time a change of task force travel direction occurs as search arcs are not dynamic.
4. Usually when the don't bother setting search arcs adherents assert that in their games they do very well without setting them they fail to point out that the DL and MDL of enemy task forces are also determined by other factors besides the efforts of their own planes flying search missions. They also fail to point out that the sheer weight of embarked planes set to search usually is much greater than what they have on land and thus the malus associated with not setting arcs is mitigated. As I said details, details which are very easy to overlook by newbies.
5. Not all sea hexes are created equal. There are frontal and backdoor approaches to most ports. How often do you really think an enemy task force is going to, or is even capable, to come in from the back door. Yet, because it is random, you will get backdoor searching if not set.
Experienced players who know exactly what they are doing and what the enemy capabilities are, can get away without setting search arcs. They save themselves some micromanagement, but that is somewhat limited as setting of search arcs for land based aircraft is largely a one time set and forget task, only needed to be revisited when a major redrawing of the sea frontlines occurs. It will superficially appear to be as effective as setting arcs, but it isn't. So the real question for you is does the additional micromanagement represent an acceptable cost for the improved search footprint obtained when setting arcs.
Unless it has been changed in the latest patch, search planes out on a random setting do not daily adjust their search area to eventually cover (over a period of time) all 360 degrees. A random setting starts off at 0 degrees and subject to having sufficient aircraft assigned proceeds in clock direction. If only sufficient planes have been assigned to cover 90 degrees, then that was the only coverage area (0-90 degrees) one ever had searched.