Gyroscope

A rotating mass, or rotor, mounted in such a way, that the spin axis of the rotoris free to rotate about one or more axis at right angles to the spin axis or put another way……….

any rotating mass is said to have gyroscopic properties

AIRCRAFT TYRE DEFECTS

NORMAL TREAD WEAR


Possible Causes
Even tread wear  indicates that tire pressure has been maintained at the correct inflation level during service.

Recommendation

Remove the tire from the aircraft if the reinforced fabric (bias) or the aramid cord protector (radial) is exposed, or if the remaining groove depth is less that 1.0mm at any point of the tread surface.

UNEVEN TREAD WEAR (SHOULDER)

Possible Causes

Under inflation will lead to excessive tread shoulder wear.It will also lead to high tire deflection and subsequent heat build up which may result in tire damage.

Recommendation 

If the tire wear limit has been or soon will be reached, remove the tire.

If the wear limit has not been reached, check the pressure and adjust it to the recommended value.If shoulder wear is more pronounced on one side, this type of wear could result from axle flexing. Tire can be kept in service until normal wear removal criteria is reached.

UNEVEN TREAD WEAR (CENTER)

Possible Causes

Over-inflation accelerates center tread wear, reduces tire traction and makes the tread more susceptible to cutting by foreign objects.

Recommendation

If the tire wear limit has been reached or soon will be reached, remove the tire.

If the wear limit has not been reached, check tire pressure and adjust in accordance with maintenance manual standards.

IRREGULAR WEAR / ABRASION

Possible Causes

Refers to abrasive wearing of the tread caused by sudden, strong side forces.

Recommendation

If the reinforced Fabric or Aramid Cord Protector is exposed, remove the tire.

SPOT WEAR

Possible Causes

Skid burns result from brake malfunctions or locking of the wheel, most often during landing.

Recommendation

If the spot wear reaches the reinforced fabric (bias) or aramid cord protector (radial), remove from the aircraft.

*Tires with spot wearing exposing the carcass or radial tire belts more than 10 squire inch area must be scrapped.

If the spot wear does not reach the reinforced fabric (bias) or aramid cord protector (radial), If there is sufficient groove depth in the whole spot wear area.If there is not incipient separation and if vibration is not detected while rolling, leave the tire on the aircraft.

TREAD RUBBER REVERSION

Possible Causes

An oval shaped burn on the tread most often is caused by hydroplaning on wet or frozen runways during landing.

Recommendation

If the rubber reversion reaches the reinforcing fabric (bias) or aramid cord protector (radial), if there is sufficient groove depth in the whole tread rubber reversion area.If there is hot incipient separation and if vibration is not detected while rolling, leave the tire on the aircraft.

THREAD SEPARATION

Possible Causes

Separation of the tread or fabric is caused by overloding.cuts,abnormal heat build up,etc......

Recommendation

A tire with tread or fabric separation must be removed immediately and be checked by the tire manufacture.If tread separation is serious,part of most of tread (Often including the reinforcing fabric in bias tires) may peel off,which in turn may be lead to damage to the aircraft.there for remove the tire immediately.

Early signs of tread separation can manifest themselves in the form of a tread bulge, local uneven wear (depression) or a local tread/ sidewall rubber split.remove the tire immediately.

If the tire is still inflated after aircraft is at parking position, record the pressure after it has cooled down (allow 3 hours).Then deflate the tire before removing the wheel assembly.

CONTINUED.......... 

Protection and Location of Flight Recorders (black box)

Flight recorders for the retrieval of data for accident investigation purpose must be adequately protected and so located in an aircraft that the recording media will survive in the event of a crash situation .The adverse factors against which protection is necessary are mechanical damage due to impact and acceleration forces,fire damage,and chemical attack by hydraulic,de-icing and fire extinguishing fluids,fuels and acids.Protection must also be afforded against the effect of sea water,and to cater for cases where an accident occurs resulting in wreckage entering deep water,the recording medium container must also be provided with separation and flotation facilities. 

                      The protection facilities are,of course,'built in' to the design of a recorder and so may be considered as the primary means of ensuring survival of the recording media.The location of a recorder in an aircraft is, however, also an important factor to be considered in this respect, and from the evidence of aircraft accidents it is shown that the rear fuselage and tail unit structure is the section most likely to survive, or be the least severely damaged.For this reason therefor,a protected flight data recorder is installed in the rear of an aircraft.

                     In addition to the foregoing protection and location requirements,it is also necessary to provide recorders with means to facilitate their identification in conditions following a crash.This is usually done by adopting a distinctive color scheme;thus, contrary to the 'black box' cliche frequently adopted in news media reports of a crash, the box could well be fluorescent orange.