Greek investigators have taken part in a re-enactment aimed at determining what caused a Cypriot airliner to crash near Athens in August.
A fire at the crash site made the identification of bodies difficult
All 121 people on board died when the Helios Airways Boeing 737-300 lost cabin pressure and hit a hillside.
Greek investigation chief Akrivos Tsolakis said the re-enactment was unprecedented for Greece.
A Greek F-16 fighter jet also flew alongside the plane on Monday, as happened on the fatal day.
"We hope certain basic questions will be answered," said one of the investigators, Serapheim Kamoutsis.
Monday's reconstruction flight left Larnaca airport at 1107 - two hours after the original flight on 14 August - due to the position of the sun, the AFP news agency reported.
An Olympic Airways Boeing 737-300 was used, taking the same flight path as the Helios jet.
As a mark of respect, the re-enactment was given the symbolic flight number 121, in memory of the crash victims.
1999: Established as first independent airline in Cyprus
2000: First chartered flight
2001: First scheduled flight
Flies to UK, Strasbourg, Sofia, Athens, Dublin, Warsaw and Prague
Operates four Boeing 737 planes
Coroners said those on board the Helios jet were alive - though possibly unconscious - when it crashed.
A pressure valve left in manual mode is thought to have contributed to the crash by failing to adjust the in-flight cabin pressure.
All but 11 of the victims were Cypriot.
The crash orphaned 47 Cypriots, 26 of them children.
A flight attendant is believed to have tried to take control of the airliner during its final moments.
The pilots of two Greek F-16s who shadowed the airliner just before the crash said they saw the co-pilot slumped over the controls and the captain was missing from the cockpit.
Flight 522 had been heading for Athens en route to Prague when it lost contact with air traffic controllers, sparking a security alert before it crashed.
GREECE AIR DISASTER
1. 0900 [0700GMT]: Helios Airways Flight ZU522 leaves Larnaca bound for Prague via Athens
2. 0920 approx: Plane reaches cruising altitude of 35,000ft
3. 0937: Plane enters Greek airspace
4. 1007: Air traffic control unable to contact aircraft
5. 1030: Greek ATC issues "Renegade alert"
6. 1055: Two F16 fighter aircraft scramble
7. 1120: F16s intercept aircraft; pilots observed slumped over controls
8. 1205: Aircraft crashes near Grammatikos, 40km north of Athens