Computer failure or HAL’s botched upgrade — what Mirage 2000 crash probe is looking at

A Mirage 2000 jet fighter aircraft

New Delhi: The probe into the fatal 1 February Mirage 2000 crash in Bengaluru is focusing on the possibility of either a computer failure or a botched upgrade by state-run Hindustan Aeronautics Ltd having led to the incident.

Two Indian Air Force (IAF) pilots testing the upgraded Mirage 2000, Squadron Leader Samir Abrol and Squadron Leader Siddhartha Negi, were killed in the crash at the HAL airport in the Karnataka capital.

Top sources in the defence establishment said the court of inquiry (CoI), headed by an Air Commodore who is an experienced Mirage 2000 pilot and a former Air Attache in France, is still in the process of pin-pointing the exact cause of the crash.

There is difference of opinion among the team members and the stakeholders, said the sources.

Computer failure or unfitted screws?

Sources said French aeronautics firm Safran made computer controls for the aircraft and it is suspected that the pitch rate gyrometers — the sensors that calculate the aircraft’s altitude — sent a wrong input.

Fighters like the Mirage 2000 are programmed to accept commands from the flight computer to keep the aircraft stable. Flight computers also play a role in release of the missiles or bombs on board in conflict.

“The CoI is now looking at what caused this wrong input. Was it a software problem or was it because three out of the four necessary screws on the sensors were not fitted,” a source in know of the CoI proceedings said.

HAL is carrying out an upgrade of the Mirage 2000 fighters, manufactured by the French firm Dassault.

Sources said the French firm had sought the sensors to be handed over for analysis but HAL refused to do so.

Arrester barrier failure

ThePrint had reported on 20 March that the CoI found that the crash was caused by an “uninitiated control input” — or a software glitch — during the jet’s user acceptance trial.

It established that the aircraft was about five metres from the ground, its nose pitched sharply down when the fully loaded fighter jet hit the runway on its main wheels and tail.

The CoI also ruled out any human error and found that the arrester barrier at the runway failed, eventually leading to the death of the two pilots.

The arrester barrier is a net with two hydraulic jacks that is installed at the end of runways to ensure an aircraft does not overshoot it.

The IAF continues to fly the upgraded Mirage aircraft despite the CoI looking into a possible software glitch.