The size of a hole to be drilled depends upon its purpose and can differ by the diameter, size
of the shaft and on the manner which the hole/shaft combination will be used.
Also, if the hole is to be reamed, hole should be smaller to allow for the metal
removed by the reamer. Drill sizes are fixed and written on charts with each
standard drill size, clearance and tapping sizes. There are several classes
of fit defined by the relationship between the bolt hole and the bolt.
A Clearance Fit, a Interference Fit and a Transition Fit.
How is safety in the aircraft hangar
Aircraft maintenance environment danger is increased by the
required machines, tools and materials. Personal safety includes
dress and eye and ear protection, operating with familiar and good
equipment from the workshop.
Pedestrian and fire lanes should be marked and never obstructed
by the non-technical personnel.
Spillage of oils OR fuels should be immediately
covered with absorbent material and cleaned preventing
spillages into floor drains.
Location of First Aid and fire fighting equipment
must be known to the personnel.
Fuel tanks, rotating propellers and operating turbojet engines
present a serious risk of injury or death and every effort to
prevent that should be taken.
Sound safety program and an aware workforce as one of
technician primary job duties can reduce such risks.
EWIS
This section is divided into three parts. The first addresses the levels of
Inspection applicable to EWIS, the second part provides guidance for
Performing zonal inspections, and the third part provides lists of
Installations and areas of concern.
Level of inspection applicable to EWIS
Detailed inspection DET intensive examination of a specific item,
Installation or assembly to detect damage, failure or irregularity. Det can be
Morethan just an visual inspection, it may include tactile assessment in
Which a component or assembly is fof security.
Genaral visual inspection – visual examination of an interior or exterior area,
Installation or assembly to detect obvious damage, failure or irregularity.
Zonal inspection a collective term comprising selected GVI and visual checks
That are applied to each zone, defined by access and area to check system and power
Plant installations and structure for security and general condition.
EWIS GVI
A visual examination of an interior or exterior area,
Installation or assembly to detect obvious damage, failure or
Irregularity. This level of inspection is made from within touching
Distance unless otherwise specified. A mirror may be necessary
To enhance visual access to all exposed surfaces in the inspection area.
Stands, ladders or platforms may be required to gain proximity to the
Area being checked.
Trought flashlights and mirrors may be required to provide an adequate
View of all exposed surfaces, there is no requirement for equipment removal
Or displacement unless this is specifically called for in the access instructions.
Paint and/or sealant removal is not necessary and should be avoided unless
The observed condition is suspect.
It is expected that the area to be inspected is clean enough to minimize
The possibility that accumulated dirt or grease might hige unsatisfactory
Conditions that would otherwise be obvious.
Observations of discrepancies, such as chafing, broken clamps, sagging
Interference, contamination etc. need to be adressed
TOWING AIRCRAFT
It is often necessary to move an aircraft without using its engines.
Large aircraft are towed with a tractor, or special towing vehicle,
And are connected to the vehicle with a special tow bar.
Extreme care must be used to avoid towing and aircraft too fast
And to be sure that there is always sufficient elereance between the
Wings and any obstructions.
When an aircraft is being towed, a qualified person should be in the cockpit
To operate the aircraft brakes when needed. Extra personnel should be assigned
To watch the wing tips and tail for clereance between other objects.
Damaged can be quite extensive, requiring replacement of the nose gear shock struct.
Persons riding in the aircraft should not attempt to steer the nose wheel when a towbar
Is attached to the aircraft.
When pushing an aircraft, be sure to push only at points that are specified by the aircraft
Manufacturer. Never push an control surfaces or in the centre of a struct.
Coaxial cable Coaxial cable contain two or more separate conductors.
The inner most conductor may be solid or standed copper wire, and may be plain,
tinne, silver plated or even gold plated. The remaining conductors are in the form
of tubes, usually of fine braid. Outer coverings or jackets serve to weatherproof the
cables and protect then from fluids, and mechanical and electrical damage.
Coaxial cable have several advantages over standard cables.
Firstly, they are shielded agains electrostatic and magnetic fields.
Secondly coaxial cables do not radiate, then likewise they will not
pick up any energy or be influeneed by magnetic fields. Thirdly coaxial cable have specific
valves of impedance, capacitance per unit lenght and attenuation per unit lenght.
