Incident Overview
On 3 January 2013, an Airbus A321-211 (registration EC-HUI) was being pushed back from Stand 522 at London Heathrow Airport when a serious incident occurred. The aircraft was destined for Madrid, Spain. The pushback procedure initially proceeded normally, and the flight crew received clearance from the ground crew to start the engines.
Sequence of Events
According to the commander's report, the towing control lever on the nose landing gear was not correctly set. As the right-hand engine was started, the nosewheel steering system became pressurised, resulting in damage to the nose landing gear assembly. The ground crew immediately stopped the pushback procedure. After explaining the situation to the flight crew, the aircraft was towed back onto the stand. It was subsequently inspected and removed from service pending maintenance action.
Aircraft and Crew Information
The Airbus A321-211 (year of manufacture 1999, serial number 1027) was equipped with two CFMI CFM56-5B3/P turbofan engines. The aircraft had six crew members on board; the number of passengers was not reported. No injuries were reported among the crew, and passenger injuries were also not reported. The commander, aged 58, held an Airline Transport Pilot's Licence and had 15,961 total flying hours, including 5,131 hours on type. His flying experience in the last 90 days was 103 hours, with 45 hours in the last 28 days.
Technical Background
The nosewheel steering mechanism is hydraulically powered and is normally inhibited during pushback to allow the tow vehicle to manoeuvre the aircraft without damaging the steering system. This inhibition is achieved by action on a towing control lever located on the nose landing gear, operated by ground crew. When the control lever is in the towing position, a "NW STRG DISC" message appears on the flight crew's display.
Reported Cause
The commander reported that the towing control lever was not correctly set, leading to the pressurisation and subsequent damage to the nosewheel steering system when the right engine was started.