1956 vintage Convair started out as a 440 for Swissair. Ten years later it was sold to Martin's Air Charter (Martinair) as PH-MAL where it was converted to 640 standard. Imported to the USA in 1971 by Omni International as N640R. The aircraft joined the fleet of the new Zantop International Airlines in 1972 when they bought it in June. It went on to fly with Zantop for the next 25 years.