11.2 Airframe structures Flashcards
1
Q
what does PSE stand for
A
principle structural elements
2
Q
name some examples of principle structural elements
A
wings, canard, vertical stab, horizontal stab, winglets
3
Q
what are flight limit loads
A
maximum loads expected in service
4
Q
what are ultimate limit loads
A
flight limit loads multiplied for safety
5
Q
what are aircraft structural members designed to do
A
carry load or resist stress
6
Q
what are the 5 stresses acting on an aircrfat
A
tension, compression, torsion, shear, bending
7
Q
structural members are designed to carry what loads instead of what loads
A
end loads rather that side loads
8
Q
what are the 3 ways structure is classified
A
primary, secondary, tertiary
9
Q
what falls under primary structure
A
any of the aircrafts framework
10
Q
name some example of primary structural components
A
wing spars, engine mounts, fuselage frames, main floor
11
Q
what falls under the secondary structure
A
non-primary structural components
12
Q
name some secondary structure examples
A
wing ribs, fuselage stringers, aircraft skin segments
13
Q
what falls under tertiary structure
A
any remaining structural components
14
Q
what must you refer to when identifying aircraft structure
A
AMM, SRM
15
Q
what is meant by fail safe
A
duplication of structural members so if one fails there is a backup
16
Q
whats the disadvantage of fail safe structures
A
added weight and the concept is outdated
17
Q
what is the modern concept that is replacing fail safe
A
damage tolerance
18
Q
describe the safe life concept
A
prediction of how long a structure can remain in service until a point of fatigue
19
Q
what is the safe life concept recorded in
A
cycles or operating hours
20
Q
what is damage tolerance concepts
A
testing of structures
21
Q
what types of test are used for tolerance concepts
A
static and dynamic load tests
22
Q
what are the 5 main aircraft structural units
A
fuselage, wings, stabilisers, flight control surfaces, landing gear
23
Q
what are used to calculate primary dimensions on an aircraft
A
defined zones, reference points, lines, planes
24
Q
what type of zones is the aircraft split into
A
major zones, major sub zones, zones
25
what number are all the zones and what part of the aircraft do they cover
100 - lower half fuselage
200 - upper half fuselage 300 - empennage
400 - power plants/struts
500 - LH wing
600 - RH wing
700 - LG/LG doors
800 - doors
26
what is used to identify sub major zones
second digit of number code
27
are the sub major zone numbers odd or even on the LH/R|H side of the aircraft
odd is on the left, even is on the right
28
what are the zones identified using on the aircrfat
third digit of the number
29
how is the aircraft zones numbers (e.g top to bottom)
fwd - aft
inb - outb
bottom - top
30
what do the digits mean when identifying zones
first - major
second - sub major
third - zone
31
what does BS and FS stand for
body stations, fuselage stations
32
where does the body station run on the aircraft
vertically at right angle to body centreline
33
where does the fuselage station run on the aircraft
from the nose of the aircraft
34
what does BL stand for
buttock lines
35
what is the buttock line 0
bodies centreline
36
where are buttock lines on the aircraft
vertical planes parallel to body
37
what does WL stand for
waterline
38
where do waterlines run on an aircraft
horizontally at right angles to body stations and buttock lines
39
what does WS stand for
wing station
40
what does CS stand for
component stations
41
what are all the major types of stress
tension, compression, torsion, shear, stress, bending, hoop stress, strain, fatigue
42
define tension
resistance to forces which pull it apart
43
define compression
stress that resists crushing forces
44
define torsion
stress that causes twisting
45
define shear
stress that resists force that causes a layer to slide over another layer
46
define stress
material subject to a force
47
define bending
stress combination of compression and tension
48
define hoop stress
what cabin experiences when its pressurized (radially and axially)
49
define strain
ratio of the amount of deformation of material caused by stress
50
define fatigue
effect of cyclic or altering loads on structural components
51
what part of the fuselage are drains located
lower half
52
how is the loss of air during pressurisation prevented
by using bilge like valves
53
what must aircraft designers consider when fitting components
access panels and how to get components out with ease
54
what does LRU stand for
line replacable unit
55
how are cables grouped to make it easier for serviceability
looms
56
what is the most basic lightning strike protection on modern aircrfat
external metal structure
57
what is used on composite aircraft for lightning strike protection
metallic paint, conductive mesh
58
if a lightning strike is reported what must you first do
walk around, find any damage
59
what 2 types of damage can a lightning strike cause
direct, indirect
60
what is direct lightning damage
burned surface, or distortion , damage to the structure
61
what is indirect lighting damage
damage to electrical systems
62
how big is the scorch mark that a lightning strike usually creates
3mm diameter
63
how big will a high intensity lightning strike scorch be
6mm or more in diameter
64
what are 2 signs of lightning strikes
discoloration, damaged rivets
65
where are the most common parts for lightning strikes
nose, trailing edges, edges of wings/stabilisers
66
can lightning strikes go through the aircrafts metal structure and cause internal damage
yes
67
what is bonding
joining two electrical conductors together
68
what is grounding
electrically connecting conductive objects to either another conductive structure or a conductive return path
69
what type of electricity can an aircraft be charged with during flight
static electricity
70
whats the process of electrical bonding
connecting components to ensure the have the same electrical potential
71
proper bonding will enhance what
protection of equipment and passengers
72
when installing grounds, what conditions apply
.separated AC/DC/shields
.no more than 4 terminals in 1 stud
.dual grounds installed in fuel vapour areas
73
what are frames also known as
formers
74
what is the use of frames/formers
give shape and strength
75
to overcome the strength problem on monocoque construction what is used
semi-monocoque
76
whats the purpose of bulkheads
give shape to the fuselage
77
whats the purpose of bulkheads in the engine
seal/isolate fire zones
78
what is a longeron
main longitudinal member of the fuselage
79
what is a stringer
smaller and lighter longeron
80
whats used to attach the skin to the frame
clips or cleats
81
what are doublers used for
reinforce areas of skin that require extra strength
82
whats another type of doubler
crack stopper
83
what do struts and ties do
provide structural integrity and airframe strength
84
what force do struts take
compression loads
85
what forces do ties take
tension
86
what are ties usually made from
steel or titanium
87
what are floorboards made from
honeycomb composite
88
what are the 2 general fuselage construction types
truss type, monocoque type
89
whats the main advantage pf semi-monocoque fuselages
can withstand more stress and still hold together
89
what is a truss type fuselage usually covered with
fabric
90
what are semi-monocoque fuselages primarily made from
aluminium alloys
91
how can a skin be joined together
bonded or riveted
92
what does an empenage consist of
horizontal and vertical stabiliser
93
what do engine nacelles do
house engine components
94
what is used to bind skins together and structural components
rivets
95
why are blind rivets used
to rivet areas that cant be accessed by a block
96
what is used for joining on aircraft when high strength is needed
bolts
97
whats a substitute to bolts when strength isnt needed
screws
98
what is used for bonding, especially on composites
adhesive
99
what does surface protection prevent
corrosion, fluid damage, erosiom
100
101
what are the 3 groups for protective treatment
pre-treatment, paint coatings, special coatings
102
what is done in pre-treatment of surfaces
de-greasing, applying a pre-treating substance
103
what are the 2 pre-treatment subsatnces
anodising, chromating
104
what does anodising do
forms oxide coating to increase surfaces performance
105
what does chromating do
produces protective oxide film
106
what colour finish is chromating
browny-yellow
107
whats the reason for applying paint to an aircraft
protect skin from corrosion
108
what is paint coatings divided into
primer, topcoat
109
what are the 2 types of special coating
type 1, type 2
110
what does a type 1 special coating do
water repellent
111
what does a type 2 special coating do
heavy duty corrosion preventative
112
what are the 3 methods of cleaning the exterior of the aircraft
wet wash, dry wash, polishing
113
what can polishing be broken down into
mechanical, hand
114
when is a wet wash used
to remove oil, grease, or carbon deposits
115
when is a dry wash used
remove aircraft film, dust and small dirt
116
117
117
118
why do we polish an aircrafts exterior
restore brightness/colour
119
before commencing cleaning what musty you do with panels
ensure they are closed and sealed
120
what must not come into contact with acrylic windows when cleaning
undiluted solvents
121
when an aircraft flies in areas prone to slat hows it washed
with water after flight
122
after an aircraft wash what must be done with the windows
wash windows with soap or detergent in warm water
123
what areas are prone to corrosion in the aircrafts cabin
galleys, toilets, drains
124
why must an aircraft all be in alignment
to ensure it flies correctly
125
what is the alignment check with on aircraft
transit and plumb bobs or theodolite and sighting rods
126
on small aircraft what is used for measuring
steel tape
127
what is used for measuring larger distances
spring scale
127
how are dimensions of a large aircraft measured
marking the aircraft on the floor with chalk then using a plumb bob
