Turkey caught peeking in Syria's back yard
Full details have yet to be revealed, but it has been confirmed that Syria shot down a Turkish RF-4E Phantom II. The details yet to be confirmed are whether or not this aircraft was actually inside Syrian airspace. The plane went down in the Mediterranean Sea, but it is not clear where it was when it was hit by Syrian fire. It is also not clear, whether or not the pilots have been recovered or are even alive.
...
Assuming the RF-4E violated Syrian airspace, it is hardly likely that was a navigation error. The RF-4E is used to gather electronic and photographic intelligence. Turkey is aiding the Free Syrian Army and it is certainly expected that Turkey would gather aerial intelligence for them. Electronic intelligence can be gathered by the RF-4E without violating Syrian airspace. But, if there were specific photographic intelligence needed from a direct over flight, the aircraft would have to fly into Syria to obtain it.
If the RF-4E were over Turkish airspace and shot down, that raises another possibility which is that someone inside Syria grew concerned this aircraft may have detected signals or electronic emissions between Russian military units inside Syria. If Russian officers are leading Syrian units on the ground, piloting attack helicopters in the air, or Russian SPETSNAZ are on site seeking targets for air and artillery strikes, then that would be direct intervention in Syria which Russia has insisted no nation should do. Suspicion of Russian involvement on that scale, may likely by why the RF-4E was present in the area in the first place.
Whoever shot down the aircraft, this is technically an act of aggression against a NATO nation which would require a response from NATO itself. Turkey may have been seeking to gather evidence of a Russian presence and take it to NATO in order to be rebuffed and have the domestic political justification to act unilaterally in Syria, especially if Turkey is able to prove that it was Russian action which brought down their aircraft. It is highly unlikely NATO would act as an alliance and would probably site Turkish harboring of the Free Syrian Army inside Turkey, as reasoning for remaining neutral.
http://www.examiner.com/article/turkey-caught-peeking-syria-s-back-yard