The sister of an RAF sergeant killed when his aircraft was shot down in Iraq plans to sue the Ministry of Defence over his death.

Sarah Chapman, whose brother Bob O’Connor, 38, was one of ten servicemen killed in the single biggest loss of British forces in Iraq, wants compensation from the Government on the ground that too little was done to protect the troops.

Mrs Chapman, 33, also wants assurances that extra safety systems will be implemented to protect planes from enemy fire. She has support for her intended action from the parents of another victim of the flight, Richard and Pauline Stead, whose 35-year-old son, Flight Lieutenant David “Steady” Stead, also died.

Sergeant O’Connor, from the RAF’s 47 Squadron, which supports the Special Forces, died after the Hercules C130K was hit by hostile fire on January 30, last year. He was not married but had a long-standing partner, Col Knight.

The aircraft, which had taken off six minutes earlier, was brought down after an explosion in a fuel tank, which had been hit by enemy fire. The crew reported the aircraft on fire six minutes into the “routine operational passenger and freight flight” from Baghdad to Balad and it was confirmed missing twenty-five minutes later. The crash site was found by US helicopter crews twenty minutes after that.

A report published by the MoD in December said that the vulnerability of the aircraft’s fuel tanks — which were not fitted with a fire suppression system — was a factor in the incident. It recommended that the system, which replaces oxygen with an inert gas to avoid explosions, should be considered for C130s.

Mrs Chapman, who lives with her husband, Stephen, and daughter, Maddie, in Histon, Cambridgeshire, has learnt that there had been calls for the equipment to be introduced.

She is also calling for the MoD report’s recommendations to be implemented. She has learnt that the MoD planned to fit the system to some Hercules.

“Having the system could have given them 20 minutes to land and they were only six minutes from a coalition airfield. You can imagine how, as a family, we feel.

“This is not new technology. America has had it since the 1960s and Australia has it.”

Mrs Chapman, a nurse at the neuro-intensive care unit at Addenbrooke’s Hospital, Cambridge, will join other bereaved military families in London next week to put pressure on Mr Blair to meet them.

A petition will be handed into Downing Street after the families have laid flowers at the Cenotaph in Whitehall.

“I am not letting Bob’s death go unanswered,” Mrs Chapman said. “Troops are not just expendable assets. They are sons and brothers and they need protecting. You cannot sustain the ‘can do’ culture of the forces with the makeshift culture of government.”

A spokesman for the MoD said yesterday that no official claim had been submitted by Sergeant O’Connor’s family and, until then, no comment could be made. He added that the official board of inquiry had been held into the incident and recommendations made — one of which was to fit fire-retardant protection on the aircraft. “Prior to this incident it was not thought that the aircraft was vulnerable to a fuel tank explosion,” the spokesman said.

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