Was born in Berne on March 28, 1931. After the compulsory school, frequently interrupted for health reasons, he did an apprenticeship as smith. In that period with the money he had spared he learned how to fly gliders. He obtained his glider pilot licence on September 10, 1950. In January 1951 he started the school to be trained as an airplane pilot and obtained the private pilot licence on May 24, 1951. He then did aerial towing of sailplanes and at the same time he obtained the qualification as an acrobatic pilot. In 1953 he accepted an offer from the local aero club for a job as a mechanic. In the following years he became chief-mechanic and continued to fly obtaining, among others, the qualification as an instructor and glaciers pilot. In the meantime he was employed by the Alpar aviation company. The latter company was responsible for the maintenance of the Heliswiss helicopters.
At the beginning of the 1960s there was a lack of pilots in Switzerland. Consequently Tschumi was asked if he wanted to become a helicopter pilot. On August 12, 1961 he did a flight check with the chief-pilot Leo Kunz. The following October 6, he then begun the school and did his first solo flight on October 15, after seven hours of training. On November 6, after having logged 23 hours of flight, he obtained his private pilot licence. The following year on May 11, 1962 he obtained his commercial pilot licence n° 53 after having logged 50 hours of flight on the Bell 47G2. On November 12, 1963 he completed the extension for mountain landings.
Until May 1, 1964 he continued to fly with Alpar's airplanes and Heliswiss' helicopters as a reserve pilot. By that date on he was employed as a full time commercial helicopter pilot by Heliswiss. In January 1965 he obtained the qualification as an instructor.
Until that moment he only flew with helicopters of the Bell 47 series. Later on he piloted larger helicopters such as the Agusta-Bell 204B and the Sikorsky S-58T.
It must not be forgotten that Walter is one of the pioneers of the aerial assembly in Switzerland. He was the first to assemble pylons, antennas, etc. using a helicopter. In the spring of 1978 he became chief-pilot of Heliswiss. He continued to fly after his official retirement on March 31, 1996. He did his last flight as a flight instructor on August 22, 1997.
During his long aviation career he logged altogether 12'092 hours of flight and 109'400 landings. The long series of models piloted include: the Bell 47 series, the Agusta-Bell 204B, the SA. 330 Puma, the Sikorsky S-58T, the Bell 206 Jet Ranger, the Bell 214B-1, the SA 315B Lama, the Schweizer 300C, the Robinson R-22, the MBB BO-105, the Alouette III and the Bell 205.
Tschumi wrote notes about his experiences and when he found out to be much suffering he gave the manuscript to his close friend Markus Burkhard. Tschumi’s memoirs, who unfortunately died on March 27, 2003, are now in the book “Blick zurück, mein Leben als Flieger im letzen Jahrundert” (A look back, my life as a pilot in the past century), accompanied by wonderful pictures. This book is a "must-have" for all who are keen on helicopters.