Medical certificates 4 months validity extension Posted on 26 March, 202030 March, 2020 by Greek Helicopters Validity of medical certificates, expiring between 01.03.2020 and 31.07.2020 is extended to 31.07.2020. All must be renewed by 01.08.2020. Excluding those who have time limit (TML) and must be revalidated on the given date. Share this:Tweet