Wizz UK A321 at London on Jan 16th 2020, late rotation on takeoff

Last Update: October 8, 2020 / 15:05:29 GMT/Zulu time

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Photo of Wizz Air UK G-WUKG, Airbus A321 — Wizz Air UK G-WUKG, Airbus A321 (Photo credit: Alec BHX/KKC / Flickr / License: CC by-sa)

Incident Facts

Date of incident
Jan 16, 2020

Classification
Report

Airline
Wizz Air UK

Flight number
W9-2602

Departure
London Luton, United Kingdom

Destination
Prague, Czech Republic

Aircraft Registration
G-WUKG

Aircraft Type
Airbus A321

ICAO Type Designator
A321

A Wizz Air UK Airbus A321-200, registration G-WUKG performing flight W9-2602 from London Luton,EN (UK) to Prague (Czech Republic) with 157 passengers and 7 crew, was accelerating for takeoff from Luton's runway 26, when the first officer, pilot flying, initiated the rotation for takeoff at Vr, the aircraft however did not respond. The first officer pulled the stick to near fully aft, the aircraft still did not respond. The captain (32, ATPL, 8,305 hours total, 5,175 hours on type) applied TOGA thrust at which point the aircraft began to rotate, lifted off and climbed out to safety. The aircraft subsequently continued to the destination without further incident.

The British AAIB released their bulletin reporting the A321 had been assigned to the flight at last moment in replacement of an A320. Seat assignmet for the passengers had been done based on the A320 layout, which left the rear seats of the aircraft empty and placed the CG of the aircraft forward outside the permitted forward limit of the operating envelope. The unusual distribution of passengers was not noticed by dispatcher or cabin crew. The captain of the flight remained unaware of the unusual distribution of passengers in the cabin, according to the loadsheet he was handed the weight distribution and CG was within limits. V1 was computed at 112 KIAS and Vr at 123 KIAS.

The AAIB wrote:

Due to the standard ‘POSITIVE RATE OF CLIMB’ call being missed, the landing gear was not retracted until approximately 5,000 feet amsl. The flight was continued to Prague during which the crew analysed the problem and were informed by the Senior Cabin Attendant (SCA) that there were no passengers at the rear of the cabin. The actual passenger distribution did not match the load sheet distribution, which distributed passengers equally throughout the cabin. Close to the top of descent, the conclusion was made that the take-off stabiliser setting on the load sheet was incorrect and this had caused the delayed rotation. It was not realised at that time that the CG was out of limits. It was assumed that the CG was within limits and that the aircraft’s auto-trim system had compensated for the different distribution once the aircraft had become airborne. A normal descent, approach and landing was carried out at the destination with no pitch control abnormalities experienced. Subsequently, it was discovered that the aircraft loading had placed it outside the permitted CG envelope.

The AAIB analysed:

The incident occurred due to the aircraft change from an A320 to an A321 not being notified to both OHD and PSD. As a result, the passengers were seated at the front of the aircraft, placing the CG outside the forward limit of the operating envelope. The effect of this was that, at rotation, the aircraft appeared to the crew not to respond as expected to the normal side stick control inputs due to the forward CG. The PF required almost maximum aft control input and the PM selected TOGA thrust before the aircraft nose lifted. The crew analysed the problem but considered that an incorrect stabiliser setting, taken from the load sheet, had caused the problem. 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.