Kollsman's altimeter gives the pilot the ability to set the existing atmospheric pressure while in flight and adjust the altimeter to those conditions. By doing so, the altimeter was accurate within 20 feet and enabled pilots to fly "blind." The display of the atmospheric pressure on the altimeter is still often referred to as the "Kollsman Window."
A native of Freudenstadt, Germany, Kollsman came to the United States in 1923 to sell a radical type of automobile engine that he couldn't sell in Germany. When that idea still proved unsuccessful, he joined Pioneer Instrument Company in Queens, New York. He left the company to start his own business, the Kollsman Instrument Company, in Brooklyn, New York, to develop an accurate barometric altimeter, unlike the crude altimeters in use at the time. Kollsman, Inc., is now located in Merrimack, New Hampshire, and specializes in the design and manufacturing of avionics flight instruments, night vision equipment, lasers, and medical diagnostic equipment.
Kollsman was awarded the Guggenheim Medal for his notable achievement in the advancement of aeronautics. He died in 1982 at age 82 in Los Angeles, California.