Shoreham Airshow organisers were unaware of a pilot’s display plans before his jet crashed, killing 11 people, a report has found.

The Air Accident Investigation Branch (AAIB) said a risk assessment carried out ahead of the 2015 show did not “show the range of hazards presented by different display aircraft”.

The AAIB’s special bulletin also revealed there was “no evidence of an attempt to consider either a hierarchy of protection or control” before the Hawker Hunter plane crashed onto the busy A27 in West Sussex on August 22.

The report found the air show’s flying display director (FDD) was an experienced display pilot, but did not have details of the manoeuvres pilot Andrew Hill planned to perform.

The report says: “Without prior knowledge of… (the jet’s) display routine or the ground area over which the pilot intended to perform it, it was not possible for the FDD to identify the specific associated hazards, where the various aerobatic manoeuvres would be conducted, and therefore to determine which groups of people would be exposed to those hazards and to what extent.”

The AAIB commissioned an agency of the Health and Safety Executive to review the air show’s risk assessment.

It found “a number of deficiencies compared to what would have been expected”.

The review added: “It is not clear that those who assessed the risks and recorded the assessment had a full understanding of the purpose of the risk assessment.”

The AAIB also criticised how spectators outside the airfield – so-called secondary crowds –  were looked after, including those around the junction of the A27 where the plane crashed.

In previous years, several hundred people watched the displays from there, and the AAIB said stewards had been employed to ask people to move on.

But the report goes on to say: “Neither the organisers nor the police had requested or been granted the legal power to prevent people from being in this area and their efforts did not prevent gathering on the A27 junction.”

The AAIB recommends that the Civil Aviation Authority specify a minimum separation distances between secondary crowd areas and displaying aircraft.

If such an order had existed at  the time of the Shoreham crash, the plane would not have been allowed to fly where it did over the A27.