The IFF helps air defence radars identify whether an aircraft or helicopter is friendly or hostile.The sources said the GCM held Group Captain Chowdhury guilty of not following laid down norms, especially orders issued by the Air Headquarters on IFF.The helicopter crashed in Budgam around 10 am on February 27 when Indian and Pakistani fighter jets were engaged in fierce aerial combat in Nowshera, a day after Indias air strike on a Jaish-e-Mohammed terrorist training camp in Balakot in Pakistan.