The photo provided by Police Graubuenden shows the wreckage of the old-time propeller plane Ju 52 after it went down went down Saturday Aug, 4 2018 on the Piz Segnas mountain above the Swiss Alpine resort of Flims, striking the mountain's western flank about 2,540 meters (8,330 feet) above sea level. All 20 people on board were killed, police said Sunday, Aug. 5, 2018. (Polizei Graubuenden via AP)

Geneva - Swiss tourist airline Ju-Air plans to restart operations on August 17, days after 20 people died when one of its vintage aircraft crashed in the Alps.

The announcement came Tuesday as rescuers finished recovering the remains of the 17 passengers and three crew members from the Piz Segnas mountain in eastern Switzerland.

Switzerland's Federal Office of Civil Aviation said in a statement that it could not ground Ju-Air's remaining two planes unless there were indications of a technical defect.

The office added, however, that "Ju-Air must ensure that the crews and maintenance staff are mentally able to guarantee safe flight operations."

"We will conduct conversations with all our staff," Ju-Air spokesman Christiane Gartmann said, adding that no one would be forced to fly.

The small airline, which is based in Duebendorf near Zurich, is operated by volunteers, including seasoned airline and military pilots.

The aircraft that crashed on Saturday was one of Ju-Air's three German-built Junkers Ju-52 aircraft from 1939 that originally belonged to the Swiss air force.

The cause of the accident has not been established. Based on eyewitness accounts, aviation experts say that the aircraft likely stalled and nosedived for a yet unknown reason when it was flying a sharp turn.

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