The Excalibur Airways Airbus A320 flight left eight hours late from London's Gatwick Airport on a journey to Faro, in Portugal, on 26 August, 1993, when immediately after take-off the pilot experienced a severe pull to the right, it says.
The pilot had to apply strong pressure on the control stick to keep the aircraft from rolling to the right.
During the flight the commander was unable to execute turns to the left and had to land at higher than normal speed to ensure that the aircraft did not roll to the right as it arrived.
The crew managed to keep the aircraft under control and it returned to Gatwick 37 minutes after take-off.
Engineers examining the aircraft, which had just been grounded for emergency repairs that were carried out under contract by British Airways, discovered that the spoilers, which are normally deployed to reduce lift on an aircraft on its approach to landing, had been left partly deployed.
The investigators, from the Air Accident Investigation Branch, found that this had been caused by a series of human errors and said that both maintenance engineers and the crew were responsible.
The Air Accidents Investigation Branch report said the maintenance procedures were not carried out correctly and the engineers did not fully understand the way the spoilers functioned. The maintenance crew should have seen there was something wrong before allowing the aircraft to fly.
The crew "should have detected the unfit-for-flight condition before the aircraft took off," the AAIB report said.
It added: "The emergency arose, not from any mechanical malfunction, but from a complex chain of human errors by the maintenance crew and by both pilots who earlier, despite carrying out specific checks, did not notice that spoilers on the right wing were not responding to control inputs."
There were a series of other errors which led to the potentially disastrous situation. The engineers had not complied with the proper working practices and supervisors had not properly enforced the maintenance manual procedures.
Excalibur was also criticised for not having "specified to its pilots an appropriate procedure for checking the flight controls".
The report, which makes 14 recommendations, said that two vital parts of the spoilers - known as collars and flags - were not fitted during maintenance and four of the five right wing spoilers were placed in the maintenance, rather than the active, mode.
It warns sternly: "The avoidance of future maintenance related accidents with hi-technology aircraft depends on an attitude of total compliance with approved procedures being developed and fostered within the industry."
The recommendations include making Excalibur review its procedures, ensuring Airbus Industrie amends its maintenance manuals and requiring the Civil Aviation Authority to review maintenance procedures.Reuse content