The Hash Academy

CORROSION REMOVAL, ASSESSMENT AND REPROTECTION:   Due to the high cost of modern aircraft, operators are expecting them to last much longer than perhaps even the manufacturer anticipated. As a result, the manufacturers have taken more care in the design of the aircraft, to improve the corrosion resistance of aircraft. This improvement includes the use of new materials and improved surface treatments and protective finishes. The use of preventative maintenance has also been emphasised more than previously. Preventative maintenance, relative to corrosion control, should include the:  Adequate and regular cleaning of the aircraft  Periodic lubrication (often after the cleaning) of moving parts  Regular and detailed inspection for corrosion and failure of protective treatments  Prompt treatment of corrosion and touch-up of damaged paint  Keeping of drain holes clear  Draining of fuel cell sumps  Daily wiping down of most critical areas  Sealing o...

EASA MODULE 7 SUB MODULE 7.3 TOOLS Lubrication Methods:   Solid surfaces are never perfectly smooth, as the actual rubbing contact (the friction), between two moving surfaces, is concentrated on a number of high spots on the respective surfaces. Any load between the two surfaces tends to wear away these high spots until the area of contact is large enough to support the load without further deformation.   During the wearing action fragments of the surface are broken away and high local temperatures are generated. The effects are potentially dangerous, in that the fragments can cause serious damage to the surfaces while excess heat leads to expansion of the materials.   The expansion is likely to cause higher frictional forces, leading to further damage (due to more particles breaking from the surface) and can possibly result in eventual ‘seizure’ and stoppage of movement. Seizure could have disastrous results in any moving mechanism.   Lubrication is a process for re...

EASA MODULE 7A Sub Module 7.3 TOOLS Filing Techniques:   Good filing is not just a matter of removing surplus metal. The correct amount of material, at each point on the surface of the work piece, needs to be removed, so that the dimensions and tolerances, set by the drawing, will be met. Proficiency comes with practice. New files should, if possible, be first used on soft metal. This achieves ‘tempering’ of the cutting teeth and will contribute to a longer life for the file. Before starting work, it must be ensured that the work piece is secure and correctly placed, as both hands are required for filing tasks. A file must never be used without a handle. The file will not be under full control and the risk of puncturing the wrist or palm is very great.   Files must be handled carefully. File blades, being hard, are also brittle and will break if dropped. After use, all files should be returned to their respective racks or bandolier-type holdalls, to prevent them knocking toget...

EASA MODULE 7A Sub Module 7.17 AIRCRAFT HANDLING AND STORAGE DE-ICING/ANTI-ICING OF AIRCRAFT     Ice Types There are three main types of ice/frost that can affect an aircraft’s performance, Hoar Frost, Rime Ice and Glaze Ice. The temperature and weather conditions will determine the type of ice that forms, but all three types can have a detrimental effect. The Dew Point is the temperature at which moist air becomes saturated and deposits dew if in contact with a colder surface or the ground. Above ground, condensation into water droplets takes place. Hoar Frost is a deposit of ice crystals that form on an objectwhen the dew point is below freezing point. High humidity will normally produce hoar frost, as these are similar to conditions that produce dew. Hoar frost can form when the air temperature is greater than 0°C, but the aircraft skin temperature is less than 0°C. This type of frost produces a very rough surface which leads to turbulent airflow. Rime Ice is a light c...

EASA  MODULE 7A Sub Module 7.17 AIRCRAFT HANDLING AND STORAGE AIRCRAFT FUELING PROCEDURES The use of the term ‘fueling’ can include both refueling and defueling procedures and these notes contain examples of the essential points to be considered when refueling and defueling aircraft. There may, however, be some further, local instructions, regarding the responsibilities of the various personnel involved in fueling procedures and these will always take precedence in conjunction with the relevant Maintenance Manual. Refueling When refueling the AMM should always be consulted so that the positions and capacities of the fuel tanks and also the type of fuel, position of the refuelling point(s) and refuelling procedures are known. There are two general re-fuelling methods: 1. Gravity or over-wing refuelling: which is, essentially, the same method as used to refuel a motor car (automobile), with a similar type of refuelling hose being used. As the name suggests, the filler points are, gen...

  EASA MODULE 7A Sub Module 7.3 TOOLS HAMMERS: Hammers are classified by their weight and type of head. Steel heads are forged and manufactured from high-carbon steel. Most shafts are made from straight-grained Ash or Hickory and are secured to the head by wedging. The main types of engineering hammers are : Ball Pein: The flat surface is used for most general-purpose work whilst the ball pein is used primarily for riveting-type operations.       Straight Pein: Used for general work, the narrow, straight pein being particularly suitable for use where access to the work is limited. Cross Pein : As for the straight pein, but the axis of the pein is at 90° to that of the shaft. Hide/Copper Face: The rawhide facing enables heavy blows to be delivered without damaging the surface of the work, while the copper face may be used for heavier types of work than hide faced hammers .   Rubber Head and Plastic Face: More modern versions of the Hide Face hammer. Can often...

      EASA MODULE 7A Sub Module 7.17 AIRCRAFT HANDLING AND STORAGE    AIRCRAFT JACKING: Aircraft may need to be jacked for a variety of purposes. These may include component changes, retraction tests, weighing of the aircraft and aircraft rigging checks. Care needs to be taken when jacking, to avoid damage to aircraft or equipment. Jacking points are provided in the wings and fuselage, at strong points, to enable the whole aircraft to be lifted, and there are, usually, other points, at the nose and main undercarriages, to enable individual wheels to be changed. Some aircraft require a jacking pad to be fitted to each jacking point, while in some, the jacking pads are built into the structure. Special jacking adapters and beams may be available to lift individual axles.   In all instances, the Maintenance Manual should be consulted, so that the correct equipment and procedures may be used. Because of the position of the jacking points, the C.G. of some aircr...

EASA MODULE 7A Sub Module 7.17 AIRCRAFT HANDLING AND STORAGE     AIRCRAFT TAXIING AND TOWING:      Aircraft need to be moved on the ground, between flights, for a variety of reasons, which can include:  Moving aircraft into, or within hangars for maintenance  Re-positioning aircraft for ground running or storm protection  Emergency removal of aircraft from a taxi-way.   It is important that the aircraft be moved safely, using the correct equipment, to avoid injury to personnel or damage to aircraft. Small aircraft, generally require little preparation but, with larger aircraft, some or all of the following points may be relevant: Preparation for the reception of the aircraft should be made in advance of its arrival. There should be adequate space available for the aircraft, with consideration given, as appropriate, to clearances for jacking, access for cranes etc. All equipment required for servicing should be available and serviceable. The...

LIGHTNING STRIKES   Lightning is the discharge of electricity in the atmosphere, usually between highly charged cloud formations, or between a charged cloud and the ground. If an aircraft is flying in the vicinity of the discharge or it is on the ground, the lightning may strike the aircraft. This will result in very high voltages and currents passing through the structure.     Effects of a Lightning Strike:   Lightning strikes are likely to have two main effects on the aircraft 1: Strike damage where the discharge enters the aircraft. This will normally be on the extremities of the aircraft, the wing tips, nose cone and tail cone and on the leading edge of the wings and tail plane. The damage will usually be in the form of small circular holes, usually in clusters, and accompanied by burning or discoloration. 2:  Static discharge damage at the wing tips, trailing edges and antenna. The damage will be in the form of local pitting and burning. Bonding strips ...