DESCARTES is a lightweight instrument for the measurement of long-lived trace gases. The instrument is designed to fly piggyback on other payloads, with a low weight of about 20 kg and no need for telemetry. The instrument collects samples by letting a measured volume of air pass through a tube containing a Carboxen adsorbent. With the current setup of the instrument and analysis equipment, atmospheric CFC-11, CFC-12, CFC-113, CCl4 and CH3CCl3 are adsorbed in measurable quantities. At present the instrument performance is well known for the measurement of CFC-11. Further work on the analysis method is needed before it can be determined which of the other species can be accurately quantified. The aim of the DESCARTES participation in the ILAS validation campaign has therefore been to measure CFC-11 for comparison with the satellite measurements. Preliminary profiles of CFC-11 and CFC-113 are presented for all the 6 flights of DESCARTES during the ILAS validation campaign.