A pilot experienced take-off issues at Luton Airport due to a communication error leaving too many passengers at the front of a plane, a report has found.
An email calling for an Airbus A320 to be replaced with an A321 at London Luton Airport on January 16 was not sent due to a "technical issue", said the Air Accident Investigations Branch (AAIB).
It meant the passenger seating plan for the flight that was heading to the Czech Republic was not adjusted to a larger aircraft that was recommended for the number of passengers.
AAIB said the plane landed safely and the operator has since taken action.
The Operational Control Centre (OCC) in Hungary, sent an automated message to the Operational Handling Department (OHD) and Passenger Services Department (PSD) at Luton.
"An email informing OHD and PSD of the change was prepared but, due to a technical problem, was not sent," wrote the investigators in the report.
"This was noticed later in the day, at 1405 hrs, and the OCC Duty Manager telephoned the OHD and informed them of the aircraft change."
The communication error meant that the plane did not respond to the pilot's normal take-off commands and extra thrust was needed for it to take-off safely.
It landed safely in Prague without any further incidents.
The AAIB said in the report: "Only at the top of the descent for the destination did it become apparent that the passengers had possibly been incorrectly distributed in the cabin.
"The crew did not experience any unusual control response during the approach and landing."
The AAIB did not disclose the name of the airline involved in the report.
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