British Airways A388 enroute on May 5th 2016, the square tyre

Last Update: June 3, 2016 / 13:51:05 GMT/Zulu time

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Photo of British Airways G-XLEB, Airbus A380-800 — British Airways G-XLEB, Airbus A380-800 (Photo credit: col29071962 / Flickr / License: CC by-nd)

Incident Facts

Date of incident
May 5, 2016

Classification
Incident

Airline
British Airways

Flight number
BA-32

Departure
Hong Kong, China

Destination
London Heathrow, United Kingdom

Aircraft Registration
G-XLEB

Aircraft Type
Airbus A380-800

ICAO Type Designator
A388

A British Airways Airbus A380-800, registration G-XLEB performing flight BA-32 from Hong Kong (China) to London Heathrow,EN (UK), was climbing out of Hong Kong close to reaching the top of climb when the crew received a tyre pressure indication. The crew decided to continue the flight to London and requested a tow tug to be available for landing in case the aircraft would not be able to taxi on its own. The aircraft landed safely on Heathrow's runway 09L and taxied to the gate.

The aft right outboard body tyre caused a lot of head scratching trying to explain how the stunning square shape of the damaged tyre came together (editorial note: the original of the photo does not exhibit any indication of photoshopping).

The AVH coverage even caused head scratching at Airbus, which the follwing "In Service Information" transmitted by Airbus to aircraft operators underlines:

Purpose of this Article:
This article aims at providing some explanations on a tire that was found with a square “shape” after landing.

Background

The following picture included in an article issued by “The Aviation Herald” on the 8th of May 2016 entitled "The Square tire" raised many questions.

Description

Both Bridgestone and Michelin who were consulted came to the same explanation:

1. The tire got an FOD damage or puncture that perforated the casing.

2. The tire leaked during the flight until low/zero pressure.

3. During descent, when aircraft reached a lower altitude, due to the fact that either the hole in the tire closed up (due to low pressure inside the tire) or because the size of the hole did not allow the tire pressure to increase as fast as the outside air pressure, the higher outside air pressure exerted an external force on the tire that compressed into this this strange square shape.

This is the same thing with an empty (or almost empty) plastic bottle that would be closed in altitude and that collapse during the descent due to higher ambient pressure.

Airbus is aware of a similar issue on a competitor’s aircraft. Once the tire was removed, it recovered its round shape.

It is to be highlighted that in the both cases, the tires landed fully deflated with no break up or disintegration.

We would like to remind that in such a configuration (landing with a tire fully deflated), the involved wheel and the adjacent one have to be replaced in accordance with the relevant AMM’s instructions.

The reasons for which the tire took this “square shape” are difficult to explain precisely. It is assumed this is connected to the changing stiffness of the belt plies structure, especially as the sidewalls are compressed inwards. A square seems to be an optimum shape.

It must be highlighted that this type of event is relatively uncommon and that in most of the cases the tire will be destroyed during landing due to the pressure loss.