m11.2 Flashcards
1
Q
what is PSE
A
principle structural elements- part of the a/c that contributes significantly to carrying flight and ground loads
2
Q
flight limit loads
A
the maximum loads expected in a service
3
Q
ultimate limit loads
A
flight limit loads multiplied by a factor of safety
4
Q
where can criteria for structural requirements be found
A
CS-25
5
Q
What are the 5 types of stresses
A
1- tension
2- compression
3- torsion
4- shear
5- bending
6
Q
whats special about bending
A
it is a combination of tension and compression
7
Q
what are the three structural categories
A
1- primary structure
2- secondary structure
3- tertiary structure
8
Q
secondary structure
A
less prone to weakening, wing ribs stringers etc
9
Q
tertiary structure
A
lightly stressed elements, fairing fillets
10
Q
what is fail safe
A
relies on duplication of certain structural members, if one fails the other takes on the load
11
Q
what is the disadvantage of fail safe
A
the additional weight
12
Q
what is safe life
A
- based on predicting how long a structure will last
- by submitting it to stating and dynamic load testing or fatigue testing
13
Q
what be calculated by using fail safe
A
max cycles, operating hours
14
Q
what is damage tolerance
A
uses static and dynamic testing to show the structure can withstand even higher loads than required
15
Q
when is damage detected for damage tolerance
A
during routine inspection intervals
16
Q
what are the 5 main structural units
A
- fuselage
- wings
- stabilizers
- flight control surfaces
- landing gears
17
Q
what are the reference planes
A
vertical, horizontal and longitudinal planes
18
Q
how many major zones are there
A
8
19
Q
what is zone 100
A
lower fuselage
19
Q
what is zone 300
A
empennage
19
Q
what is zone 500
A
left wing
20
Q
what is zone 400
A
power plants and struts
20
Q
how are sub major zones identified
A
the second digit of the number code
20
Q
what is zone 800
A
doors
20
how are sub major zones on the right identified
even numbers
21
what is zone 700
landing gear and LG doors
22
how are zones identified
the 3rd digit of the number code
23
what is a body station or fuselage station
a vertical plane at a right angle to the body centreline
24
what are buttock lines
vertical planes parallel to the body centreline
25
what is buttock line 0 also known as
body centreline
26
what is the abbrevieation for left body buttock line
L BBL
27
What are warterlines
horizontal planes at a right angle to the body station and buttock lines
28
where can the numbering for a/c stations be found
chapter 6 amm
28
what is hoop stress
axial and circumfrencial stress that takes place in a cyclinder
28
what is used to prevent loss of air during pressurisation
bilge like valves
29
what is fatigue
the effect of cyclic or alternating loads on structural components
29
where are drain holes located
various positions on the lower fuselage
29
when would the bilge valve be open
when the cabin is depressurised
29
what are vent pipes used for
vent flammable vapours
29
what are ram air inlets and exit points used for in terms of ventilation
to enable a full flow of fresh air
30
where are ventilation requirements found
CS-25
31
what are LRUs
line replaceable units
32
how must LRUs be designed
to allow for quick fit and removal
33
what 2 things should be done after a lightning strike
general walk around inspection
find signs of damage through detailed instruction
34
what is direct damage
surface burns
metallic distortions
35
what is indirect damage
damage to the electrical system
36
how big are holes from normal lightning strikes
3mm
37
how big are holes from high intensity lightning strikes
6mm
38
what are the most common areas for lightning strikes
fuselage nose section
trailing edges
extremities of the wings and stabilisers
39
what is bonding
the act of joining 2 electrical conductors together to bring them to the same potential difference
40
what is grounding
the process of connecting conductive objects to either a conductive structure to complete a circuit
41
what are the reasons for a/c bonding
- minimise radio interference
- eliminate fire hazards
- minimise the damage to the a/c
- provide low resistance return path
- provides shielding
42
conditions for grounding
grounds must be separated
no more than 4 studs per terminal
dual grounds must be in fuel vapour areas
43
what are the 2 types of bonding
direct
indirect
44
what is direct bonding
done by exposing the mesh and mounting the equipment directly onto a conductive path
45
what is indirect bonding
achieved by exposing the mesh and installing a bonding wire and connector
46
bonding resistances should not exceed
0.025 ohms
47
what are frames/formers
lateral fuselage members that give cross sectional shape
48
what are longerons
main longitudinal member of fuselage, that take primary bending loads
49
what are bulkheads
these give shape, but are used to close of or partition an area
50
what are used to connect stringers and fames
clips or cleats
51
what are stringers
smaller and lighter longerons that act as stiffeners. they also assist the sheet materials to carry loads along there length
52
what are struts
load bearing components, that handle compression forces (aluminium/composite)
53
what are doublers
these are additional sections or material used to reinforce areas of skin that need more strength
54
what are some doublers also known as
crack stoppers
55
what are ties
also known as tie rods or tension members, to prevent excessive deformation
56
what are ties usually made from
steel or titanium
56
what is the floorboard construction
honeycomb composite, screwed down by nut clips
57
describe the truss type construction
- members like beams, struts, and bars
- often covered with fabric
- constructed with steel tube welded together
57
what happens to floorboards in wet areas
they are sealed to prevent corrosion
58
what are the 2 types of fuselage construction
- truss type
- monocoque type
59
what are the 2 classes of monocoque construction
- True monocoque
- Semi monocoque (more common)
60
true monocoque
uses formers and frames
but the skin carries the primary stresses
61
semi monocoque
loads are shared between skin and framework
also known as stressed skin structure
62
types of anti corrosion surfaces treatmeants
painting, anodising, sealants
63
corrosion protection methods
cladding and plating
64
what does a wing construction consist of
main spar
rear spar
formers called ribs
false spar
65
how are both wings attatched to each other
via the wing box
66
what is the wing box designed to do
support the wing and is supported by a keel beam
67
3 types of surface protection
pre-treament
paint coating
special coating
68
types of pre treatment
anodising
chromating
69
2 types of paint coatings
primer- increases corrosion resistance
top coat protects the layers of primer
70
what are the 2 types of special coatings
type 1 and type 2
71
type 1 special coating is...
water repellent, made from silicone free materials
72
type 2 special coating is...
heavy duty corrosion preventative
73
what are the 3 methods of exterior a/c cleaning
1 wet washing
2 dry washing
3 polishing (hand/mechanical)
74
what is a wet wash used for
removing oil, grease, carbon deposits as well as most dirt apart from corrosion and oxide films
75
what is a dry wash used for
to remove aircraft film, dust, dirt or soil.
dry wash materials are applied with spray, mops or cloth
76
what is polishing used for
this can restore brightness/colour to painted and unpainted surfaces
normally done after the a/c has been cleaned
77
where can you find recommended cleaning solvents
relevant maintenance manual/COSHH/MSDS
78
what materials can experience hydrogen embrittlement
some steels and titanium
79
why must undiluted solvents not touch acrylic windows
crazing may occur
80
when must snow and ice contaminated areas be washed
with clean water asap after exposure
81
what are windows washed with
soap or a mild detergent in warm water
82
for interior cleaning aids, why must they be applied in small amounts
prevent soaking the fabric or padding
83
what must be done before checking the position or angle of main components
a/c must be jacked and levelled
84
what must be used when trying to level an a/c
a plumb bob, hung from the ceiling of the a/c
85
equipment for alignment checks can be found in
the manufacturers maintenance manual
86
alignment checks include
wing dihedral angle
wing incidence angle
verticality of the fin
engine alignments
symmetry check
horizontal stabiliser incidence
87
what can be used to check dihedral
a straight edge and inclinometer
88
what is used to measure symmetry
steel tape and a spring scale for equal tension
