A generation of Polish leaders wiped out and a nation in mourning - through the haze of grief gradually questions are being asked as to how this tragedy could have happened.
The plane's flight data recordings are being analysed
There were no survivors to bear witness to Saturday's plane crash, which claimed the lives of the Polish president and his wife, security chiefs, leading MPs and the governor of the national bank.
Russia's Prime Minister Vladimir Putin is heading the investigation into why the plane, carrying 96 passengers, crashed in dense fog on approach to Smolensk airbase in western Russia.
Initial Russian findings based on air traffic control conversations and flight data recordings suggest there were no technical or mechanical defects with the Soviet-era Tupolev-154.
Russia's lead investigator has pointed to the pilot's decision to try to land, despite repeated warnings of the poor weather conditions, as the most likely cause of the crash.
There has been speculation that the crew were under pressure from those on the plane to land at Smolensk - and that perhaps President Lech Kaczynski himself may have given the final order.
However, Polish officials say there is no evidence to substantiate such claims.
Russia and Poland have long had an uneasy and difficult relationship.
The Polish delegation was on its way to attend a ceremony marking the massacre of 22,000 Poles at Soviet hands in 1940.
"The pressure of the 70th anniversary of the Katyn massacre was so huge that all on board the aircraft wanted very much to land on that airbase on time," Polish aviation expert Grzegorz Holdanowicz told the BBC.
The pilot appears to have ignored advice to divert to either Moscow or Minsk, the capital of neighbouring Belarus.
With visibility poor, the pilot made a fatal attempt to land, hitting the tops of trees and smashing into the ground.
Some reports said the pilot had attempted up to four landings, though a senior Russian aviation official, Tatyana Anodina, has said that the plane only tried to land once.
Mr Holdanowicz, editor of Polish defence magazine Raport, said President Kaczynski had an apparent history of being impatient to land aircraft in unsuitable conditions.
In 2008, during Russia's brief war with Georgia, President Kaczynski flew to Tbilisi to support the Georgian president.
According to reports at the time, the president got into an argument with the pilot, who, because of the dangers of landing in a combat zone, went against the president's orders and diverted to Azerbaijan.
Former Polish President Lech Walesa said that the pilot of Saturday's doomed flight would not have made the decision single-handedly.
"I have flown a lot and whenever there were doubts, they always came to the leaders and asked for a decision, and based on that, pilots made decisions.
"Sometimes the decision was against the leader's instructions," he was quoted as saying by the Polish newspaper, Gazeta Wyborcza.
The Polish presidential plane had been in operation for almost 20 years but had recently been serviced in Russia.
The aircraft's three engines were repaired and updated with retrofitted electronic and navigation equipment.