I do not have the Official Strategy Guide, so I may be repeating information. However, to date I've never seen any corrections to (or analysis of) Air to Air Combat techniques in XCOM.

I'll do the weapon analysis here. If someone has details about Cautious/Standard/Aggressive modes, please add them! Specifically, I would like to know:
--Chance of each UFO type escaping each XCOM craft (dependent upon attack mode)
--Increase or decrease in accuracy and damage based on attack mode
--Increase or decrease in XCOM craft damage taken based on attack mode

If someone is willing to do a full analysis, I'd love to see a numerical analysis that compares UFO range, damage capability, and hull armour versus each weapon and attack mode. The Unofficial Strategy Guide gives recommendations, but I prefer statistics over prose (when available).


First, let me give the real "Accuracy" values for the XCOM craft weapons (the information in the UFOped is incorrect).



I use the following equation to calculate damage over time. Note that range is ignored.

t = time duration of combat (in game seconds)
r = weapon reload time
a = weapon accuracy
d = weapon damage


Number of shots fired = N = int (t / r)
(Maximum number of shots fired = weapon capacity)

Average number of hits = H = N * a

Average damage = D = H * d


(((Thank you, Spaceman, worked perfectly!)))




ASSUMPTIONS:
I have assumed that pilots in XCOM have no stats, therefore the listed accuracy is a strict percentage chance to hit (unlike the tactical field weapon accuracies). I also assume no accuracy change based on distance to the target, and I assume the target is in range for the duration of combat.

What does that mean? It means, I haven't taken into account the "ufo flees" event. XCOM weapons only fire when a UFO is in range. When the UFO flees, it quickly escapes the range. Shots from XCOM weapons do slightly exceed their "maximum" range, but they will not hit. This means a wasted shot--a severe penalty for the limited-capacity Avalanche, Stingray, and Fusion Ball Launcher.


SIMPLE ANSWERS:
The Plasma Beam weapon produces the most damage over time, ignoring range, for any engagement equal or more than 6 seconds in length.

The Laser Cannon produces the second highest damage over time, ignoring range, for combat durations between 6 and under 25 seconds, between 40 and under 50 seconds, and equal or more than 76 seconds in length. It produces the greatest damage over time for engagements between 4 and under 6 seconds.

The Fusion Ball Launcher produces the second highest damage over time, ignoring range, for combat durations between 25 and under 40 seconds, and between 50 and under 76 seconds.

The Cannon, PRIOR TO NEW TECHNOLOGY, produces the greatest damage over time, ignoring range, for combat durations between 2 and under 15 seconds, and engagements equal or more than 236 seconds in length.

The Avalanche Launcher, PRIOR TO NEW TECHNOLOGY, produces the greatest damage over time, ignoring range, for combat durations between 20 and under 30 seconds, and between 40 and under 75 seconds.

The Stingray Launcher, PRIOR TO NEW TECHNOLOGY, produces the greatest damage over time, ignoring range, for combat durations between 15 and under 20 seconds, between 30 and under 40 seconds, and between 75 and under 236 seconds.


BOTTOM LINE:
Prior to new technology, the Cannon has the cheapest ammunition and the greatest potential damage. Due to its limited range, every engagement will result in damage to the XCOM craft (costing repair time, not funds). However, a single Interceptor armed with dual cannon will not have problems with running out of ammunition, and it can usually (not always) take down a Medium UFO (taking massive damage in return, of course). Oddly, the Cannon is the most expensive weapon-delivery device prior to new technology, costing $30,000 (compare to the Avalanche at $17,000 and Stingray at $16,000). However, a full ammo reload costs only $4,960 (compare to Avalanche at $27,000 and Stingray at $18,000). Cannon suffer from the "lost ammunition" effect--you add ammunition in full 50-round belts even if you only need to top off a few rounds.

The Stingray Launcher has the second greatest potential damage prior to new technology, and carries enough missiles to engage UFOs that flee (causing a wasted shot or two). An Interceptor with dual Stingrays can, theoretically, take down a Medium UFO with minimal damage in return, though missed shots and fleeing UFOs will often empty the launcher without a successful shootdown.

The Avalanche Launcher has long range and is more accurate than the other starting-technology weapons. The limited capacity is its greatest weakness (though the $9000 cost per missile is a prohibitive problem during financial difficulty). It is highly unlikely for a single Interceptor with dual Avalanches to take down a Medium UFO, in my experience. Though the Interceptor will not take much (or any) damage, it will run out of missiles before it knocks the UFO out of the sky. It should have no problems with small UFOs, provided the UFO does not repeatedly flee. The (very strong) counter-argument, though, is that multiple Interceptors armed with dual Avalanches can take down large UFOs, and there is rumour of success against very large UFOs (using four Interceptors, and expect at least 75% losses).

When you have access to new technology, the Unofficial advice remains the Best advice. Research Plasma Beam Cannon. Two of these unlimited-capacity, long-range, high-damage weapons eliminates any concerns about airborne UFOs. They are expensive and time-consuming to manufacture, so putting them on weak-armoured Interceptors is wise ONLY if the Interceptor NEVER engages UFO battleships. Losing 4 Interceptors, 8 Avalanche launchers, and 24 Avalanche Missiles to a battleship is preferable to losing even 1 Interceptor and 2 Plasma Beam cannon, in my opinion.


FINAL RECOMMENDATION:
Before you have the Plasma Beam (or, before you've manufactured enough of them) I recommend mixing weapons. Stingrays and Avalanches can soften the UFO from a "Cautious" distance. When you're out of ammo, if the UFO is still airborne, switch to Aggressive and charge with your Cannon. If the UFO flees, start the next engagement on Aggressive (reducing its likelihood of fleeing). You risk taking damage, but rarely destruction, taking on Medium UFOs with a single Interceptor. You should not take on anything larger using this setup.

If you have numerous Interceptors and funds, but lack Plasma Beam technology, four Interceptors armed with dual Avalanches can take on any UFO, with very high success.

The monthly maintenance on an Interceptor equals its replacement cost, though replacing the weapons and ammo costs extra. Buy replacement Interceptors once, at the beginning of each month, and you won't suffer a significant reduction in funds compared with more conservative strategies.


That's all I've got.

Out.

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