Hindustan Aeronautics Limited , HAL is the largest DPSU with 20 production divisions and 11 R&D centres . Out of the 31 types of aircrafts producer so far by HAL , 17 have been of indigenous design. As of now it is engaged in production of Su-30 MKI , LCA Tejas and Dornier-228 aircrafts along with Dhruv-ALH , Chetak and Cheetal helicopters. This is in addition to repair and overhual of several other aircrafts and copters such as Jaguar , Mirage , Mig 21 and AN-32 etc. However this Navratana has run in to rough weather due to delayed deliveries and quality related issues with its products .