The crash of a Tupolev Tu-154M carrying Poland's senior politicians and military figures to Russia has raised an array of questions regarding the flight's operation, though answers await the end of a national week of mourning.
The Polish air force aircraft, serial number 90A-837, hit trees and crashed during a short final approach to Smolensk Severny aerodrome, killing all 96 people on board, including the country's President Lech Kaczinsky.
The main questions that arise relate to the decision to send so many national leaders on a single flight, and why the aircraft's crew made the disastrous attempt to carry out an approach when visibility was well below the minimum for the non-precision approach. Other questions relate to why the navigation aids available at Smolensk were not supplemented for a flight carrying such a high-profile delegation. The aircraft, arriving from Warsaw on 10 April, had been approaching runway 26 at Smolensk North in fog. Images from the scene show that the jet's wreckage is displaced to the left of the runway's extended centreline, and that the direction of the debris trail bears some 30° to the left (see diagram).
CIS Interstate Aviation Committee (MAK) leader Tatyana Anodina has stated that the Soloviev D-30KU engines were "in working order" until the aircraft collided with an obstacle. She added that preliminary analysis of the recorders showed no evidence of in-flight fire or explosion or on-board equipment failure.
In addition, communications with the aircraft were normal, and the pilots did not report any problems to air traffic control. Smolensk ATC says it had, however, suggested to the pilots that they consider diverting to Minsk or Vitebsk in Belarus, or Moscow Vnukovo. The problem with those airports is that they are all more than four hours by road from Katyn, the ultimate destination for the Polish delegation, where they were to attend a commemoration of a massacre of Polish officers 70 years ago during the Second World War. Diverting would have made the officials late for the scheduled ceremony.
The Tu-154M's 35-year-old captain had a total of 3,528h, of which 2,937h were on Tu-154 aircraft. His co-pilot had 506h on the type from an overall 1,939h. There was also a navigator on board, who had 59h on the Tu-154 but had also flown as a Yakovlev Yak-40 pilot, as well as a senior technician.
SMOLENSK ACCIDENT: THE CIRCUMSTANCES
Smolensk Severny (Smolensk North) aerodrome is a former air force base, decommissioned by the military in October last year but now used as Smolensk's sole civil/military airport. It has no precision approach aids, and meteorological observations provided there do not meet International Civil Aviation Organisation specifications. There were no special arrangements made for the Polish presidential flight. Three days before the accident, the same aircraft had flown from Warsaw to Smolensk carrying the Polish Prime Minster, so the crew of the presidential flight should not have faced any unknowns.
About 90min before the presidential Tupolev Tu-154 was due to arrive, a Polish air force Special Air Transport Wing Yakovlev Yak-40 carrying journalists landed at Smolensk in mist. About 30min before the presidential flight was expected, a Russian air force Ilyushin IL-96, bound for Smolensk carrying Russian Federal Security Service staff, was ordered to divert because the weather was below minimums. In Russia, air traffic control can give orders to military flights, but both Polish flights had civilian status.
According to Russian air transport regulator Rosaviatsia, the aircraft was so low on short final approach that it hit an 8m (26ft) high tree when still 1,200m from the runway threshold. At that point it should still have been at 60m height, says Rosaviatsia.
When decommissioned by the military, Smolensk Severny had surveillance radar and a Russian RSPB beacon, a navigational aid like the western military TACAN (tactical air navigation) which offers bearing and range from the beacon. The status of the RSPB and the airport surveillance radar on 10 April has not been confirmed. If surveillance radar were available, the crew could have been provided with non-precision lateral and range guidance on the approach to the runway. Reports suggest that ATC was providing vectoring guidance.