People flock to air displays to see thrilling flying. The fact that it looks dangerous is part of the attraction.

It turns out – in case anyone ever doubted it – that display flying is very dangerous. But mainly to the pilot rather than the audience. The UK Air Accident Investigation Branch has just put some figures to the display flying accident rate, which had not been done before.

The AAIB reveals that the fatal risk to display pilots at UK air shows is nearly twice that to pilots at US air displays.

This deep examination of the whole business of air display safety is the official reaction to the crash in August 2015 of a Hawker Hunter T7 jet onto a busy road next to Shoreham airfield during an air display routine. The pilot survived, but 11 people on the A27 road died – the first time since 1952 that UK air show onlookers have been killed.

The final report is not yet complete, but the AAIB has issued two interim reports and a load of recommendations.

The AAIB has now estimated that the fatal display accident rate in the UK is one accident causing death or serious injury per 219 display hours. The agency explains: “Over the ten years to the end of 2015 there were nine display accidents in which the aircraft was destroyed and either a fatal or serious injury resulted.  This equates to one such accident per 219 display hours or 456 such accidents per 100,000 flying hours of which – historically –  55% have involved fatalities.” Those figures were reached by assuming the duration of the average individual display routine is eight minutes.

By comparison, the fatal accident rate for UK general aviation activity as a whole is 1.5 fatal accidents per 100,000h. That makes display flying roughly 300 times as dangerous as the GA flying average.

Another AAIB revelation makes clear why they have decided it’s time to tighten up display flying management. The report says: “Among UK display accidents, 65% involved the aircraft crashing outside the area controlled by the organisers of the display.  This equates, at 2015 levels of activity, to one display aircraft crash in an area accessible to the public every 1.7 years.”

It seems everyone knew air display flying was dangerous, but not precisely how dangerous. I suspect the attitudes that allowed this regime to continue unquestioned until now are inherited, dating back to the early days of flying when thrills and spills were considered all a part of the fun, and providing spectators didn’t get hurt, that was fine.

The Shoreham inquiry has also thrown up the fact that the existing rules governing the conduct and management of air shows were sound, but they were often not tightly policed. It turns out that the Shoreham flight display director (FDD), a display pilot and former CAA safety expert, was not required specifically to know in advance the sequence of aerobatic manoeuvres the Hunter was to carry out – and he did not know them.

Yet there was also a requirement that the FDD conduct a risk management assessment of the display, and that could not be done without knowing the planned sequence.

If the FDD had checked the Hunter’s planned sequence and speeds in advance, he would have discovered that – at many points in the routine – the aircraft would inevitably exit from the permitted display areas defined by the location of built-up areas close to the airfield. Indeed the same aircraft, displaying the previous year, had done just that, but no-one got hurt so it was ignored.

This is just one example of the fact that the main requirement for improving display safety is to apply existing rules more strictly, rather than rewrite them completely.

The rules about how display flying and air shows should be conducted are set out in the CAA’s publication CAP 403. Perhaps the key statement in it is this: “The impromptu, ad hoc, unrehearsed or unplanned should never be attempted.” That means every part of every routine must be known by all parties, rehearsed before the show, and strictly adhered to.

If that rule alone – which had always been there – were to have been applied strictly at Shoreham in August last year, the crash would not have happened. Indeed the Hunter routine that led to disaster would either have been banned or modified considerably to make it comply with existing rules.