‘Fly by wire’ fault may have led to Sukhoi crash

What has puzzled investigators is that the fly by wire system — that has replaced hydraulic controls by digital systems on all modern fighters — had quadruple redundancy. This means that all parts of the system were backed up four times,making it difficult for all of them to fail at once.

However, the sudden and involuntary 270 degrees ‘bunting’ manoeuver that sent the fighter into an uncontrollable spin leading to the crash has led experts to consider a malfunction in the system.

Russian experts who have been called in from Sukhoi Corporation are also being consulted in the matter.

“It is very difficult to imagine that the fly by wire system could have collapsed just like that,given that it was backed up four times independently. However,this was a very strange crash and this seems to be a probable explanation,” an expert said.

Earlier,Air Force experts were also considering that a structural fault,like a piece of the tail fin or wing collapsing during flight,could have led to the crash. This line of thought was brought on by the grounding of the Russian MiG 29 fleet earlier this year due to structural faults.

What makes the fly by wire system especially essential in modern fighter aircraft is that without it,the aircraft loses its aerodynamic stability. Essentially,the system ‘forcibly’ keeps a fighter in the air and any failure would lead to the fighter going out of control — like the uncontrollable spin the Su 30 MKI went into before crashing.

Meanwhile,Air Chief Marshal Fali Homi Major has described the crash as a “setback” to the Air Force while talking to reporters in Shillong. Confirming that precautionary checks were being carried out on the fighters,he said that investigations were on to identify the flaws.