No, there is no evidence to support "a setup".
There where two independent official investigations, one by Interstate Aviation Committee (IAC; Russian: Межгосударственный авиационный комитет, МАК), one by Polish Ministry of Defense's Committee for Investigation of National Aviation Accidents (Polish: Komisja Badania Wypadków Lotniczych Lotnictwa Państwowego; KBWLLP). Also participating in IAC's investigation were numerous accredited experts from Poland, and in some parts of investigation, regarding US made avionics, included two experts from US (one from FAA and one from NTSB).
While reports differed slightly on who's more to blame, both concluded that causes where thick fog, pilot errors, ill prepared airfield and errors in communication between control tower and pilot. Two big points of discrepancy are:
- whether there was pressure from President or Air Force Commander-in-Chief to land. Russian report states that there was such a pressure, Polish report does not address the issue
- errors committed by control tower: Russian report clears them of responsibility, as they did not give permission to land, OTOH Polish report points out their failures (see points relating to "Approach Control" and "LZC" in report below);
Polish final report (in English)
3.2. Cause and Circumstances of the Accident
3.2.1. Cause of Accident The immediate cause of the accident was the descent below the minimum descent altitude at an excessive rate of
descent in weather conditions which prevented visual contact with the
ground, as well as a delayed execution of the go-around procedure.
Those circumstances led to an impact on a terrain obstacle resulting
in separation of a part of the left wing with aileron and
consequently to the loss of aircraft control and eventual ground
impact.
3.2.2. Circumstances Contributing to the Accident
1) Failure to monitor altitude by means of a pressure altimeter during a
non-precision approach;
2) failure by the crew to respond to the
PULL UP warning generated by the TAWS;
3) attempt to execute the
go-around maneuver under the control of ABSU (automatic goaround);
4)
Approach Control confirming to the crew the correct position of the
airplane in relation to the RWY threshold, glide slope, and course
which might have affirmed the crew's belief that the approach was
proceeding correctly although the airplane was actually outside the
permissible deviation margin;
5) failure by LZC to inform the crew
about descending below the glide slope and delayed issuance of the
level-out command;
6) incorrect training of the Tu-154M flight crews
in the 36 Regiment.
3.2.3. Conducive circumstances
1) incorrect coordination of the crew's work, which placed an excessive burden on the aircraft
commander in the final phase of the flight;
2) insufficient flight
preparation of the crew;
3) the crew‘s insufficient knowledge of the
airplane's systems and their limitations;
4) inadequate
cross-monitoring among the crew members and failure to respond to the
mistakes committed;
5) crew composition inadequate for the task;
6)
ineffective immediate supervision of the 36 Regiment's flight training
process by the Air Force Command;
7) failure by the 36 Regiment to
develop procedures governing the crew's actions in the event of:
a)
failure to meet the established approach criteria;
b) using radio
altimeter for establishing alarm altitude values for various types of
approach;
c) distribution of duties in a multi-crew flight.
8)
sporadic performance of flight support duties by LZC over the last 12
months, in particular under difficult WC, and lack of practical
experience as LZC at the SMOLENSK NORTH airfield.
Other circumstantial evidence:
The captain of the 2010 flight was co-pilot on infamous 2008 presidential trip to Tibilisi, Georgia, where pilots refused president's "order" to change flight plan and fly into a war zone (original flight plan was to fly to Baku, Azerbaijan and get to Tibilisi by ground transport). President Kaczyński later called them cowards (exact quote: "an officer should be less fearful"), and demanded their prosecution. (see eg. Telegraph article)
In 2008 there was a crash in Mirosławiec, which bears lot of similarities:
- Air Force transport, pilots with similar training as PLF 101 pilots
- crashed attempting to land in thick fog
- ignored procedures
- ignored EGPWS/TAWS warnings
- top brass on board, which might have added pressure to land
As for alternative "investigation" by conspiracy theorists, it's based on opinions of 3 "experts", all of them academic scientist, neither of them directly specializing in aviation (their specialization is: civil engineering, spectroscopy and explosives). All of them are friends (from the 1980's opposition times) of Antoni Macierewicz, the man behind the conspiracy theory. These scientist did not visit the crash site, they had no access to any physical evidence. The opinion of the "explosives expert" is based on allegedly holding a small piece of metal (allegedly plane fragment) in his hand for a few seconds. Other "expert" based his opinions on the model he created using software to simulate... car crashes. Opinion on plane's aerodynamics was given by... spectroscopy expert.
Some more "mainstream" conspiracy theory points, and why they are not true:
- The fog was artificial — allegedly created with TMC-65 machine.
According to KBWLLP experts, plane does not behave any differently in natural or artificial fog, it's just as safe or unsafe to land in either one, so it wouldn't be the cause of the accident. Also, it's not physically possible to create 200km² of artificial fog.
- There where two explosions on board — KBWLLP checked the wreck and bodies for any signs of explosion. None were found. Nor was it recorded by CVR or any other recording device.
- Landing Zone Controller intentionally fed crew false data — KBWLLP report found that approach radars in disrepair, one of them wasn't properly attached and had up to 10 degrees of vertical sway. The hardware was never intended for precision landings in zero visibility. So while data was inaccurate, it could not be attributed to malice. KBWLLP also notes, that in such situation LZC is only providing additional information, while it's the aircraft's crew, who is fully responsible for verifying aircraft's position.
