The crash of a MiG-21 Bison in Ambala today has put a question mark on the IAF’s ambitious upgradation programme for the fighter fleet. In the past six months, two upgraded MiG-21 Bison of the Ambala-based III squadron, a frontline operational squadron, have crashed, both apparently due to technical defects. According to sources, the last MiG-21 Bison, which crashed last September 9, was due to a fault in the fuel pump supply, leading to an engine flame-out. The IAF had slated 125 aircraft for upgradation and it has already lost two in less than a year. While the upgraded aircraft has better avionics, more pods to carry a greater range of weapons and boasts of a better radar, the engine and the airframe has remained the same. In fact, it is the engine (R-25) which raised eyebrows when IAF started investigating the last crash. It is understood that the investigating authorities identified several causes — lack of proper maintenance, suspect quality of fuel, storage conditions for the pump to choke. Sources said that these issues had been highlighted to the Defence Minister George Fernandes and then Minister of State for Defence Production Harin Pathak, as well as senior officials of the Hindustan Aeronautics Ltd (HAL) which has been entrusted the upgradation programme. Sources said that after the crash of the upgraded Bison last year, several measures were suggested including strict checks, fuel discipline and storage conditions. Incidentally, the upgraded MiG-21 has a black box which enables crash investigators to pinpoint the exact cause of a crash. Investigators will now be poring over the data from the black box of the MiG-21 which crashed this morning. IAF sources say that prima facie investigators have ruled out a problem in the fuel pump and are looking into other causes. They say the aircraft experienced trouble while taking off and could not gather the required thrust. ‘‘We are looking at the parts and we should be able to ascertain the cause of this particular crash,’’ said IAF sources.
