MIAMI – Investigating authorities have determined that an incorrect weight distribution caused by distributing passengers incorrectly forced a Wizz Air UK (W9) Airbus A321 to take off out of its gravity center envelope, a FlightGlobal report said.

The inflight Crew already experienced problems when the aircraft took off of London Luton Airport (LTN) on January 16, when the sidesticks did not respond after rotation.

According to the report, the aircraft “became airborne after the first officer applied almost full aft side-stick and the captain selected full take-off thrust.” Investigation documents mentioned that the A321 was not the aircraft originally scheduled to operate the flight.

“Analysis of the situation revealed that a 180-seat Airbus A320 had originally been scheduled to operate the flight. When the aircraft was switched to a larger 230-seat A321, the passenger distribution was not revised – resulting in all 157 passengers being seated in three forward cabins and none in the aft,” the report stated.

Wizz Air UK at Luton Airport. Photo: Mike Burdett

No A320 Assignment Message Sent

UK Investigators told FlightGlobal that the A320 assignment was passed on to W9’s LTN operational handling department, but, per the report, “when the airline’s operational center in Budapest later swapped the A320 to an A321, a technical problem prevented the message being sent.”

Even though a new load sheet was made, the passenger services department did not revise the seat allocation and boarding. The captain and the first officer were using that same incorrect load sheet, missing the ‘positive climb’ while keeping the landing gear extended until reaching 5,000ft. Only during descent procedures did the Crew start noticing problems.

“During the service to Prague the crew was informed that there were no passengers in the aft cabin, which did not match the distribution on the load sheet,” the reported stated, adding that “the crew did not realize the center-of-gravity was outside limits and believed the delayed rotation had been caused by an incorrect horizontal stabilizer setting.”

UK’s authorities said in the inquiry that “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.” All 164 people on board survived after landing in Prague (PRG) with no other abnormalities.

Featured image: Wizz Air UK, Airbus A321-231. Photo: Anna Zvereva