An aerobatic pilot went into an inverted spin after feeling a jolt run through his aircraft over the north Norfolk coast.

The Air Accidents Investigation Branch (AAIB) has just released a report into the incident, which took place at Mundesley on January 9, at around 3.15pm.

The pilot, who was not named in the report but is from Aylsham and was 51 at the time of the incident, was unharmed.

He had been flying a single-engine CAP-231 plane when a control arm mount detached from the rudder, and the assembly of the fin also failed.

North Norfolk News: File photo of a CAP-232 aerobatic plane, similar to the CAP-231 which was damaged midair at Mundesley.File photo of a CAP-232 aerobatic plane, similar to the CAP-231 which was damaged midair at Mundesley. (Image: Guillaume Paumier/WikiCommons)

After the plane fell into the spin - a manoeuvre that type of aircraft is capable of doing - the pilot regained control and flew back to Northrepps Airfield, where it was based.

Kevin Smith, chief instructor the airfield, said: "On the day in question he returned to the airfield quite quickly, because the aircraft wasn't responding as it normally would.

"He put it down to him having a bad day. I think he was more in shock at finding [the damage] the next day."

Mr Smith said the aircraft, which was around 30 years old, had not flown since the incident, and had since been sold, needing repairs.

The AAIB said the exact cause and sequence of the failure could not be determined.

Their report said: "The pilot had completed several high energy manoeuvres, and as he neared the end of the display sequence and was conducting a vertical left roll, he felt a 'jolt' through the aircraft, which immediately departed into an inverted spin.

"He closed the throttle and realising that there was something odd about the yaw control, he gently recovered the aircraft to level flight using the ailerons."

The report said the aircraft was designed for high-energy, aerobatic flight, and the manoeuvre which put it into the inverted spin did not put an abnormal load on its rudder.

It said: "The nature of the damage to the fin, rudder and fairing made it difficult to ascertain the initiating event.

"The pilot was experienced in the manoeuvres he was flying and had done the same routine many times before."