Aircraft Tires and Wheels Inspections

 EASA PART 66
MODULE 7
Aircraft Disassembly, Inspection, Repair and Assembly Techniques

Tyres:

Tyres have their serviceability indicated by the depth of the groove in the tyre tread. The AMM gives information of what constitutes a worn or damaged tyre. Apart from normal wear, other defects, that can affect a tyre, are cuts, blisters, creep and low pressure.

Most tyres can be re-treaded a number of times after they have reached their wear limits, but the re-treaded can only be completed if the complete tyre has not been damaged badly.

 Creep is the movement of a cover around the rim, in very small movements, due to heavy braking action. This movement is dangerous if the tyre is fitted with a tube, as the movement can tear the charging valve out of the tube, causing a rapid loss of pressure.

To provide an indicator, small white marks are painted across the wheel rim and the tyre side wall cover so, if creep takes place, the marks will split in half and indicate clearly that the tyre cover has moved in relation to the wheel rim.

The installation of tubeless covers has reduced the problem of creep, as the valve is permanently fitted to the wheel. It is still possible for tyres to creep a small amount, but the air remains in the tyre as the seal remains secure.

Tyre-inflation devices usually consist of high-pressure bottles fitted with a pressure-reducing valve or a simple air compressor. The pressure a tyre should be inflated to depends on various factors such as the weight of the aircraft.

The correct pressure for a specific aircraft is given in the relevant AMM for the aircraft in question. It is possible for a tyre to lose a small amount of pressure overnight. A pressure drops of less than 10% of the recommended pressure is not unusual, but the exact figures are given in the AMM.

If a tyre is completely deflated with the weight of the aircraft on it, or is one of a pair on a single landing gear leg, which has run without pressure, all the tyres concerned must be replaced due to the possible, unseen damage within the cover. Again, the AMM will dictate the conditions.

Wheels

Defects to aircraft wheels are usually due to impact damage from heavy landings or from items on the runway hitting the wheel rim. Other problems can arise from corrosion starting as a result of the impact damage and the shearing of wheel bolts, which hold the two halves of a split wheel together. Wheels are usually inspected thoroughly during tyre replacement and it is very unusual for serious defects to be found during normal inspections of a wheel.

Brakes

Brake units are normally attached onto the axle of an undercarriage leg, and located inside the well of the main wheels. During braking operation, they absorb large amounts of energy as heat. This results in the brake rotors and stators wearing away and, if they become too hot, the stator material
may break up. Inspection of brake units between flights is essential, to check for signs of excessive heating and to ensure that they have not worn beyond their limits.
 

Wear results in the total thickness of the brake pack being reduced, which means that by measuring either the thickness of the pack, the amount of wear can be monitored. Once the amount of wear reaches a set figure, the brake pack will be overhauled.

If the pads are breaking up there will be signs of debris, excessive amounts of powder and, in extreme cases, scoring of the discs. This will require immediate replacement of the complete brake unit.

A rejected take-off at maximum weight will produce the maximum possible amount of heat and wear. It is usual to replace all brake units and main wheels after this has happened, but again the AMM will give the required information on what must be changed and when.

EASA PART66 MODULE 7 ESSAY QUESTION:

An aircraft is brought to the Ramp after rejected take-off at maximum weight. What inspections will you carry out on the Wheels, Tires and Brakes after this event.

(Note: Write your answers in the comment section below)


Comments

  1. This comment has been removed by the author.

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  2. *Muhammad Hamza Ahmed*

    Inspections that should be carried out after a heavy landing on an aircraft are ,

    wheels are usually inspected thoroughly during tyre replacement and it is very unusual for serious defects to be found during normal inspections of the wheel so we must see all the wheels with detail inspection to find out the damage, further more we should see if a complete tyre is deflated with the weight of the aircraft on it or is one of a pair on a single landing gear leg , which has run without pressure , all the must be replaced due to the possible unseen damage with in the cover.
    During braking operation , they absorb large amount of energy as heat this results in brake rotors and stators wearing away and , if they become too hot , the stator material may break up so inspection of brake units between flights is essential to check for signs of excessive heating and to ensure that they have not worn beyond limits.
    We must follow the authorized AMM to do the inspections

    ReplyDelete
  3. A rejected takeoff can cause a multitude of problems because of excessive weight.

    Tyre: if a tyre is completely deflated with the weight of aircraft or is one of a pair of a single landing gear leg, which has run without pressure, all the tyres concerned must be replaced due to unforeseen damage.

    Wheels: defects on aircraft wheels are usually due to impact damage from heavy landings and the impact may damage shearing of wheel bolts. Wheels are usually inspected during tyre replacement and it is unusual for serious defects to be found during this inspection.

    Brakes: a rejected takeoff at maximum weight will produce maximum possible amount of heat and wear. It is usual to replace all brake units and main wheel after this happened.

    All of these inspection should be done according to the relevant maintenance manual.

    ReplyDelete
  4. Since there is a rejected take-off and landed with the maximum weight then we have to inspect the brakes,wheels and tyres.
    To inspect this we will do general inspection of tyres.we will check creeping of tyres if there creeping exists but if it is tubeless tyres there is very less chance of creeping.If there is heavy landing at maximum weight then we should also inspect the tyre if it is completely deflated then we will change all the tyres.
    We will also do general inspection of wheels also we will only inspect the bolts of the wheels.There will be also corrosion on the wheels and its bolts we should also inspect that.
    We should also do general inspection of the brakes.If brakes heats up then rotors and stators also heat up then stators will brak down.we should also do the inspection of brakes that if they worn off or not.In pads there will be debris and excessive amount of powder we should also clean them.
    We should also consult the AMM for changing of the tyres.

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  5. When an aircraft return from a heavy rejected takeoff it should be inspected and the most probable parts that will wear and should be inspected are tyres and brakes because they wear the most.
    Tyre wear when subjected to hard breaking and it’s serviceability is determined by the depth of the grooves in the tread of the tyre. It can be replaced if necessary but this will be dependent on what is recommended in the relevant AMM. Creep can also occur when hard breaking is done. In creep the cover moves over the wheel ( rim ) and can cause the pressuring valve to break and loose all the pressure in the tube rapidly, this problem is normally associated with the tyre having a tube. Tubeless tyres don’t have this problem because the charging valve is permanently fitted and even if the tyre creeped a little bit it won’t be a concern if the seal is not broken. Tyres with tube should be inspected for any creep. This is done by marking a white spot on wheel cover ( tyre ) and wheel. If they are splitter in half then the tyre suffered from creep.
    Breaks wear allot when subjected to rejected takeoff. Severe wear will result in debris falling off the breaks, large amount of powder on breaks and in extreme conditions there will be scoring of the discs. Temperature of rotor and stator of the breaks will increase if hard breaking occurs. If the temperature of rotor increases stator will start to break. Procedures relating to the replacement of tyre and breaks will be stated in the relevant AMM.

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  6. After rejected takeoff at maximum weight following inspections will carry out on wheels brakes tyres.
    The landing gear area is such a hostile environment that the technician should inspect the landing gear including the wheels, tires, and brakes whenever possible.
    Wheel bearings showing any defects will usually need to be replaced. inspection of the wheel halves in accordance with the wheel manufacturer’s procedures must be performed due to the stresses that may have occurred.check the cracks on wheel sometime tyre overheated check the temperature check the wheels shearing of wheel bolts. Creep can also occur when hard breaking is done. In creep the cover moves over the wheel ( rim ) and can cause the pressuring valve to break and loose all the pressure in the tube rapidly, this problem is normally associated with the tyre having a tube.temperature of the rotor of brake increase when hard brake occur These inspection must be done according to manufacture manual.

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  7. As The Aircraft has Rejected take-off at maximum Weight the following inspection should be carried out on Wheels,Tyres and Brakes

    WHEELS:
    It Is Unusual to Find any serious defect on Wheels on normal inspection however the wheel can be damaged due the items on runway that hits the wheel The wheels are usually damaged due to heavy landings as a result the corrosion can start and the bolts holding the two half of the wheel can shear apart.

    TYRES:
    The serviceability of the tyre depends upon the depth of the groove tread
    The defects on the tyre other then normal wear are Cut,Creep,blister and low pressure
    It is normal for the tyre to loss an small amount of pressure over night Which the amount of pressure lost should not be greater then 10% of the total pressure.
    As the aircraft have Rejected take-off at maximum Weight the creep is likely to Happen which is the relative movement of the tyre with the wheel the movement is dangerous from the facts the the valve of the tyre tube if used can tear and can cause lose of pressure
    To ensure that the creep has happened or not it can be confirmed by the white marks painted on the wheel and the tyre wall cover if not aligned confirms that the creep has happened
    The probability of the creep to happen can be greatly reduced by the use of tubeless covers in which the valves are fixed to the wheel the creep still can happend but the air remains in the tyre as the seals are secured
    If a single the Tyres are completely deflated then the all the concerned tyres should be replaced .

    BRAKES:
    The Brakes are attached onto the axle of the undercarriage leg,located in the well of the main wheel
    As the aircraft has rejected take-off the brakes are applied which absorb a large amount of energy as heat. The heat can cause the rotors and stators to wear and of become too hot can cause the stator to break up.
    Inspection of the brake can be done by checking the thickness of brake pack being reduced. If reduced to the set figure the brake packs should be overhauled
    The wearing of the packs can give the sign of debris, excessive amount of powder and in extreme cases wearing of discs. This will require the complete brake unit to be replaced

    All the precautions should be taken according to the Relevant AMM before changing or maintaining any parts or components
    Aimal Khan

    ReplyDelete
  8. The inspection is the process of systematically examining, checking and testing aircraft structural members, components and systems, to detect actual unserviceable conditions.
    Inspections are carried out of the following tyres wheels and brakes they should be inspected properly as the aircraft brought to ramp from rejected takeoff in maximum weight.
    As we have to inspect the aicraft tyres after the landings some defects like normal wear can occur in tyres as we have to see that the tyres wear reached their limit or not they should be inspected properly. After the landing creeping is also an defect occurs in tyres it should be inspected properly. As we have to inspect the tyres generally if they have deflatad tyres or not if they have tree should be changed.
    In the ramp we should generally insect the wheels. Wheel should be inspected in way if they have impact damage or not after heavy landings. Wheels rims should also be inspected as if they have damage or not after the heavy landings . Wheels are thoroughly inspected during tyres replacement as we should have to inspect the corrosion in it. As it very unusual for the Serious defects to be found during normal inspections of the wheel.
    After the rejected takeoff brakes inspections should also be carried because of the heavy landing after it as it can effect the breaking system. General Inspections of the brakes should be done. Wear in The rotor and statirs of the brakes should be inspected as they weared away or not after the excessive heat is present in between them after the heavy landings. Inspections of the brakes units should also be carried out .
    Inspections of all the aircraft parts should be sone by qualified maintenance personnel after concerning the relevant maintenance manual.

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  9. When the aircraft brought to the ramp after rejected takeoff following inspections must be done on the tyre wheel and breaks.
    On tyres creep can occur if the pilots had applied heavy breaks but this problem can only occur on the tyres which have tube, tubeless tyres don’t face such type incidents because pressure valve is permanently fitted with the tyre which will not allow the seal to comeout. Tyre can also be deflated due to the low presseure and heavy weight of the aircraft.
    Wheels are usually thoroughly checked by the maintenance personnel during every check that heavy landing occur on this aircraft or not, corrosion can also effect the landing of the aircraft.
    Breaks are on the axel of the landing gears and comprises of rotors and stators when the rotors become too hot by absorbing energy on landing it will break the stators and rotors.
    When the heavy landing occurs the AMM tells us about the which thing has to be changed.

    ReplyDelete
  10. During the hard landing or rejected takeoff it is obvious that tyres can experiance some wear and tear.We will be doing below inspections on tyres , brakes , and wheels.


    Inspection on tyres: usually we should check for cuts, blisters, creep and low pressure on tyres.Creep is the movement of a cover around the rim, in very small movements, due to heavy braking. We must check for creep on the tyres with the help of small white marks which are painted across the wheel rim and the tyres side wall cover.

    Inspection on wheels: One of the problems that can happen with wheels is corrosion starting as a result of the impact damage and the shearing of wheel bolts, which hold the two halves of a split wheel toghether.

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