Three airliners landed at Birmingham Airport while a stepladder was on the runway following a mishap by maintenance workers, an investigation has found.

The metal ladder fell off the back of a maintenance pick-up truck close to the runway’s centreline, the Air Accidents Investigation Branch (AAIB) said.

It was several minutes before the two engineering technicians in the vehicle realised the stepladder was missing.

Flight crew on board the first two aircraft to subsequently land – operated by Ryanair and Jet2.com – reported that they may have seen an unusual object on the runway but were not sure.

They were followed by a Tui Airways plane, whose crew confirmed the presence of the stepladder.

A total of 426 people were on board the planes.

The stepladder – which extended to 7ft (2.1m) – was lying flat on the runway for 37 minutes before it was retrieved by the airport safety team.

The maintenance workers had used an elastic bungee cord in an attempt to secure it, which the AAIB described as “not suitable”.

More effective equipment was available but “not readily to hand”, investigators said.

Birmingham Airport carried out its own inquiry and took several safety actions intended to prevent a reoccurrence of the incident, which happened on September 8 last year.

The Civil Aviation Authority issued a safety alert to raise awareness of the event among airport workers.