Kenya Airways plane from Entebbe bursts tyres on landing in Nairobi

According to a press statement from the Airline, the plane landed in Nairobi safely and there were no injuries recorded.

"The aircraft is being inspected by Kenya Airways Engineers. There were no injuries. Kenya Airways wishes to thank all its guests for their patience and continued support and assure them that their safety is paramount," the statement reads in part.

Kenyan media reports that there was a delay in flights due to the incident.

Previous Situations

In August, A plane with 76 passengers on board was forced to make an emergency landing at Birmingham Airport when a tyre burst after takeoff. The Flybe flight 1274 from Amsterdam to Manchester was forced to ground early after passengers alerted cabin crew.

A Hawaiian Airlines plane made an emergency landing in Tokyo in JUly, bursting its tyres and forcing the closure of one runway and the cancellation of several other flights, although no one was injured, local media reported.

In July still, A tyre of an Oman Air plane flying in from Muscat burst while landing at Dar Es Salam airport in Tanzania. The airline said there were no injuries in the incident on flight WY 707, a Boeing aircraft. There were 158 passengers and six crew members on board.

In May, A Lufthansa Airbus A330 was stranded on the runway at Mumbai airport for 22 hours after four of its main tyres burst during landing. Flight LH-764, which travelled from Munich, had 163 passengers on board - none of whom were injured.

How different are Aircraft tyres

According to Skybrary, a source on aircraft related issues, tyres for aircrafts are designed to withstand extremely heavy loads for short durations, and the number of tyres could increase with the weight of the plane.

An Aviation author with Micheline tyres states that; An aircraft tire must withstand a wide range of operational conditions. When on the ground, it must support the weight of the aircraft. During taxi, it must provide a stable, cushioned ride while resisting heat generation, abrasion and wear.

At take-off, the tire structure must be able to endure not only the aircraft load but also the forces generated at high angular velocities. Landing requires the tyre to absorb impact shocks while also transmitting high dynamic braking loads to the ground. All of this must be accomplished while providing a long, dependable, reliable, service life.

In general tyres are divided into two groups, ‘Radial’ tyres and ‘Bias’ tyres. Bias ply tyres are constructed with the carcass plies laid at angles between 30º and 60º to the centre line or rotation direction of the tyre. The succeeding plies are laid with the cord at angles that are opposite to each other. This provides balanced carcass strength. Most aircraft tyres in service today are bias ply tyres. A typical tyre will be a combination of rubber, fabric and steel.

The Aircraft Tyre

 
Tread – The “tread” is made of a rubber compound which is designed to provide good wear resistance. The “tread” is the area of the tyre that makes contact with the ground. The tread of most tyres contain grooves that are designed to remove water from between the tyre and the runway surface, by doing so improving ground traction on wet runways.

Tread reinforcing ply – this is made of one or more layers of fabric and rubber that is laid half way beneath the tread grooves and top carcass ply. These plies help to strengthen and stabilise the tread area by reducing tread distortion under load and high-speed operations as well as adding resistance to puncture and cuts at the tread area.

Under-tread – The “under-tread” is a layer of rubber that is designed to improve the adhesion between the carcass of the tyre and the tread reinforcing plies

Side-wall – this is the layer of rubber that covers the outside of the carcass plies of the tyre. It protects the cord plies and contains anti-oxidant chemicals that were added during the manufacturing process. These chemicals are slowly released and aim to protect the tyre from UV rays and ozone damage.

Carcass ply – a carcass ply consists of fabric cords (modern tyres use nylon), coated by rubber. The carcass body itself is made from multiple layers of carcass plies that are laid at opposite angles to one another, each layer adds to the strength and load bearing capacity of the tyre. The carcass plies are anchored by wrapping them around bead wires, thus forming the  carcass ply turn-ups.

Liner – in a tubeless tyre, this is a layer of rubber that resists the permeation of nitrogen and moisture through to the carcass, it acts as a built-in tube It is vulcanised to the inside of the tyre and extends from bead to bead. On a tubeless tyre, the liner replaces the inner tube. For tube-type tyres a thinner rubber liner is used to prevent tube chafing against the inside ply

Bead – the bead is made of several bead wires and holds the tyre to the wheel. The bead wires are made from steel wires that are layered together and embedded in rubber to form a bundle. This bundle is then wrapped with rubber coated fabric for reinforcement. Generally, bias tyres are made with 2–6 bead bundles (1–3 per side).

Chafer – The chafer is a protective fabric or rubber laid over the outer carcass of the tyre in the bead area to protect and minimise chafing between the tyre and the wheel’s rim.

Shoulder – The area where the tread and the side wall meet

 

Common Tyre damages

Uneven Wear:  There are three types of uneven wear. This wear is common in under or over inflated tyres or to tyres where their horizontal centre line (back to front) is not parallel to the tyre’s rolling line.

Tread cuts. If the cut exposes ‘tread reinforcing ply’ (fabric) the tyre has to be removed from service.

Environmental effects- Ozone effect on tyres Most of the natural and synthetic rubber used in aircraft tyres are susceptible to ozone and will react to its presence. This will result in a degradation of the rubber which lead to cracks. Continued stress due to service causes the crack to grow until it is visible as a surface crack, at right angle to the direction of the applied stress.

Aircraft tyres, like any other rubber product, are somewhat affected by sunlight and extremes of weather. While weather deterioration does not worsen performance, it is possible to minimise its effects by tyre protective covers. These covers should be made of light coloured materials to reflect sunlight and should be placed over tyres when an aircraft is parked outside.

Scenarios for Tyre inflations

Taxiing: Long taxi patterns at heavy weights with tight turns will generate a lot of heat in the tyres, even if the brakes are used sparingly. This could cause the heat fuses to melt, resulting in a controlled deflation of the tyre. Dependent upon a number of factors, including the remaining number of tyres on the aircraft, there may be restrictions on further aircraft movement prior to the wheel being changed.

Take-off: High speed aborts generate a great deal of heat in both the brakes and the tyres and restrictions may need to be placed on the degree of ground movement that can be undertaken after an abort. The potential consequences of a high speed abort are, therefore, the melting of the heat fuses and the consequential impact as above.

Take-off: Explosive deflation/break-up due to e.g. FOD can have catastrophic consequences. There is a great deal of potential energy stored in the tyre/wheel assemblies and multiple, unrelated system damage should be anticipated. An immediate landing will be the priority. Post take-off: Rapid retraction of the undercarriage following a long, high speed, heavy weight taxi with immediate take-off, or multiple touch-and-goes during crew training, can lead to the tyres overheating in the wheel well. The heat fuses should prevent an explosive deflation, but it is not guaranteed. The main problem with this event is that the crew are potentially unaware that they have an issue with the undercarriage until secondary effects start to occur during the landing run.

Landing: A number of issues can arise from landing with a deflated tyre:

Handling issues may arise during the landing roll-out phase, and in severe cases may cause the aircraft to depart the prepared surface.

Landing with a deflated tyre will put additional strain on the remaining tyres, with an increased potential for one or more to subsequently suffer an explosive deflation due to overstress. The implication for secondary damage to the aircraft is high and the potential for rapid aircraft arrest and evacuation is enhanced.

Video by Aviation videos2012