Introduction
On 10 December 2014, an incident involving an Airbus A320-214, registered as LY-VEW and operated by Avion Express, occurred at Budapest Liszt Ferenc International Airport (LHBP). The incident was reported to the Transportation Safety Bureau (TSB) of Hungary on 12 January 2015 by Aeroplex of Central Europe Ltd. The investigation was conducted by an Investigating Committee appointed by TSB, with participation from BEA, MOT CIAAI, EASA, ICAO, BFU, and NTSB.
Investigation
The investigation focused on the chemical oxygen generators installed on the aircraft. It was determined that the generators had undergone degradation due to an allotropic transformation of tin, known as tin pest. Tin pest occurs when tin with a tetragonal crystalline structure (white tin) is cooled below 13.2 °C and transforms into a substance with diamond-shaped crystals (grey tin). This transformation is autocatalytic and can spread upon contact.
The tin-plated components of the oxygen generators were affected, leading to a loss of functionality. The investigation did not find any damage to the aircraft or injuries to persons. The occurrence was classified as an incident.
Cause
The probable cause of the incident was the degradation of the chemical oxygen generators due to the allotropic transformation of tin (tin pest) forming in the tin-plated components of the chemical oxygen generators installed on the aircraft.