1st Academic test – METAR, TAF, Pitot Static System and Flight Theory Flashcards
(106 cards)
1
Q
The METAR is a report that is issued:
A
hourly
2
Q
What kind of report is made anytime there is a significant change in weather (other than hourly) at the observation station?
A
SPECI
3
Q
How many letters will be used to show the station identifier on a METAR?
A
4
4
Q
How are temperature and dew point reported in degrees on the METAR?
A
Celcius
5
Q
The wind direction is given in degrees from ______ north and wind speed is always in ______.
A
true
knots
6
Q
What is atmospheric pressure?
DEFINITION
A
The force exerted by the weight of a column of air
7
Q
What is the standard sea level pressure in inches of mercury?
A
29.92
8
Q
What is the standard sea level temperature in degrees Celcius?
A
15 degrees Celcius
9
Q
What is the standard temperature lapse rate with altitude?
A
2 degrees Celcius per 1000 ft
10
Q
A change in 1 inch of mercury is equal to approximately _____ feet of altitude
A
1000
11
Q
Impact Pressure
DEFINITION
A
Dynamic Pressure + Static Pressure
12
Q
Define Static Pressure
DEFINITION
A
Ambient Pressure
13
Q
Which instruments depend on static pressure only?
A
VSI and altimeter
14
Q
Which instrument depends on both impact and static pressure?
A
Airspeed indicator
15
Q
What pressure affect the pitot static system?
A
Dynamic Pressure and Static Pressure
16
Q
IAS (Indicated Airspeed)
DEFINITION
A
Read from the dial om the face of the instrument
17
Q
CAS (Calibrated Airspeed)
DEFINITION
A
IAS corrected for instrument and position error
18
Q
TAS (True Airspeed)
A
CAS corrected fir density error
19
Q
Name and explain the three errors in the airspeed indicator:
A
Installation error: Misalignment of the Pitot tube with the relative wind and position of the static vents
Density error: Caused by pressure and temperature changes, air less dense as altitude increases
Instrument error: Caused by friction in the instrument
20
Q
Is the vertical speed indicator (VSI) a pressure differential measuring instrument?
A
Yes
21
Q
What does the setting knob on the altimeter change when it is turned?
A
Kollsman setting and position of the needles
22
Q
Indicated Altitude
DEFINITION
A
Altimeter indication
23
Q
True Altitude
A
Altitude above MSL
24
Q
Pressure Altitude
A
Altitude above the standard datum plane (29.92”)
25
Absolute Altitude
Altitude above the terrain
26
Altimeter setting
| DEFINITION
Standard pressure corrected to MSL
27
What is the maximum allowable error in the altimeter?
Plus/minus 75' (in academics – 70' at the flight line)
28
When flying into an area of lower pressure without resetting the altimeter, would your true altitude be higher or lower than your indicated?
Lower
29
When flying into an area of higher pressure without resetting the altimeter, would your altimeter indicate higher or lower than your true altitude?
Lower
30
If you depart a base with an altimeter setting of 29.82 and an hour later receive a new altimeter setting of 30.22, how much higher or lower than true altitude would the altimeter indicate prior to adjusting the altimeter to the new setting?
400' lower than true altitude
31
At the last reporting point, you corrected the altimeter by setting the Kollsman scale on 29.92" Hg. Prior to landing, you received a new setting of 29.80. What is your true altitude in relation to indicated altitude (before you reset the altimeter)?
120' lower than indicated altitude
32
When flying into an area of colder than standard temperature, would the indicated altitude be more or less than the true altitude.
More
33
The ________________ (instrument) stops functioning properly due to pitot icing.
Airspeed indicator
34
What is the recommended corrective action when the static system is clogged?
Switch to alternate static air
35
High DA and low air density mean nearly the same thing? (TRUE/FALSE)
True
36
What causes density error?
Nonstandard pressure and temperature
37
Which of Newtons law is involved?
1. Torque effect?
2. More power is needed to obtain a desired RPM than is need to maintain the RPM?
3. Greater load, less acceleration
1. Action/reaction
2. Inertia
3. Acceleration
38
If the airflow atop the airfoil increased, static pressure ________ and dynamic pressure _________.
decreases
increases
39
Center of Pressure
| DEFINITION
The point along the chord line of an airfoil through which all aerodynamic forces are considered to act
40
Definition of Airfoil
| DEFINITION
Any surface designed to produce lift when air is passed over it
41
Two basic types of airfoil:
Symmetrical and unsymmetrical
42
Straight line from the leading to the trailing edge
Chord
43
The length of the rotor blade from the point of rotation to the tip of the blade
Span (blade span)
44
Rotational relative wind
| DEFINITION
The flow of air parallel and opposite to the flight path of an airfoil
45
Induced flow
| DEFINITION
Downward flow of air through the rotor blades
46
Resultant relative wind
| DEFINITION
Rotational relative wind modified by induced flow
47
How is the angle of incidence measured in a rotary-wing aircraft?
The angle between the chord of an airfoil and the plane of rotation (tip path plane)
48
Define angle of attack
The angle between the chord of an airfoil and the resultant relative wind
49
Which flight control changes the angle of incidence differentially around the rotor system?
Cyclic pitch control
50
With an increase in the speed of air over a surface, what happens to dynamic and static pressure?
Dynamic Pressure increases
Static Pressure decreases
51
The two components of Total Aerodynamic Force (TAF)
Lift and Drag
52
Describe the relationship of lift to the resultant relative wind:
Perpendicular
53
Describe the relationship between drag and resultant relative wind:
Parallel to and in the same direction of the resultant relative wind
54
The 4 types of drag?
Induced drag
Parasite drag
Profile drag
Total drag
55
Which type of drag decreases with an increase in airspeed?
Induced drag
56
Which type of drag increases with an increase in airspeed?
Parasite drag
57
Dissymmetry of Lift
| DEFINITION
Unequal lift between advancing and retreating halves of the rotor disk
58
Relative wind velocity on the advancing blade equals blade speed ______ airspeed
plus
59
Relative wind velocity on the retreating blade equals blade speed ______ airspeed
minus
60
What causes the advancing blade to flap up?
An increase in lift
61
What causes the advancing blade to flap down?
A decrease in lift
62
How does the pilot control dissymmetry of lift?
Cyclic feathering
63
Define blowback
| DEFINITION
Change in the attitude of the rotor system
64
How does the pilot correct for blowback?
Cyclic feathering
65
Which forces in the lift equation can the pilot control?
The coefficient of lift and the airspeed
66
What are the three factors in air density (1/2 rho) that will affect in lift?
Temperature
Humidity
Pressure
67
A semi-rigid disk tilts relative to the:
mast
68
An articulated disk tilts relative to the:
hub
69
Define Centrifugal Force
| DEFINITION
Outward forced produced whenever a body moves in a curved path
70
Define rotor blade coning
| DEFINITION
Upward flexing of the rotor blades
71
Rotor blade coning is a compromise between which two forces?
Lift and Centrifugal Force
72
Define gyroscopic precession
| DEFINITION
When a force is applied to a rotating body, it will manifest 90 degrees after application in the direction of rotation
73
Why is blade twisting necessary?
To distribute the lift evenly along the blade
74
A pedal turn on the right requires ______ power than a pedal turn to the left?
less
75
Define Translating Tendency
| DEFINITION
Tendency of a single rotor helicopter to drift right while hovering
76
List four methods used to overcome translating tendency in a single rotor helicopter:
1. Rigging the cyclic
2. Tilting the mast
3. Left cyclic
4. Automatic flight control/stabilization augmentation system
77
List the four rotor blade actions:
1. Rotation
2. Flapping
3. Hunting
4. Feathering
78
Describe the relationship of total force to the tip path plane:
Perpendicular
79
When the rotor disk is tilted, what are the two components of total force?
Lift and Thrust
80
What are the two flight conditions?
Balanced and unbalanced
81
At what altitude would the aircraft be in ground effect?
Less than one rotor diameter
82
Loss, or apparent loss, of ground effect is caused by?
An altitude greater than one rotor diameter
Trees and bushes
Tall grass and uneven terrain
Hovering over water
Beginning of translational movement
Hovering into a wind
83
Effective Translational Lift
| DEFINITION
When the rotor completely outruns the recirculation of old vortices and begins to work in relatively undisturbed air
84
ETL occurs at an airspeed of:
16-24 knots
85
TFE occurs at an airspeed of:
10-20 knots
86
Settling with power
| DEFINITION
A condition of powered flight in which the helicopter settles in its own downwash
87
List the three simultaneous conditions required for settling with power:
1. Vertical or near vertical descent of at least 300 FPM
2. 20% to 100% engine power
3. Slow airspeed less than ETL
88
List the required recovery procedures for settling with power:
a. Increase airspeed with cyclic
b. Reduce collective as altitude permits
c. Adjust rotor RPM to normal operating range
89
Autorotation
| DEFINITION
The flight condition during which no engine power is supplied and the main rotor is driven only by the action of the relative wind
90
Describe how a pilot prevents rotor RPM over speed during an autorotation with turn:
With collective control
91
List the three conditions required for dynamic rollover to occur:
1. Pivot poin
2. Rolling motion
3. Exceeding critical angle
92
Dynamic rollover occurs due to a combination of which two factors?
Human and physical factors
93
Which control input is required to recover from dynamic rollover on level ground?
Smooth, moderate collective reduction
94
Operating at what speed is most likely to produce retreating blade stall?
Excessive airspeed (high forward airspeed)
95
Describe symptoms of retreating blade stall in a single rotor helicopter
Abnormal vibration, pitch-up of the nose and left roll
96
Describe the recovery procedure from retreating blade stall
Reduce collective pitch, regain control of the aircraft, reduce airspeed, increase rotor RPM to normal operating range, minimize maneuvering and descend to a lower altitude
97
Can settling with power occur during autorotation or shallow approach?
No, cause not all three conditions are present
98
Retreating blade stall factors:
PRIMARY:
1.
```
CONTRIBUTING FACTORS:
1.
2.
3.
4.
5.
```
PRIMARY:
1. Excessive airspeed
CONTRIBUTING FACTORS:
1. High gross weight
2. High DA
3. High "G" maneuvers
4. Low rotor RPM
5. Turbulence
99
METAR
Station:
Vicinity:
Distant:
Station: <5 SM
Vicinity: 5-10 SM
Distant >10 SM
100
TAF is valid for _____ hours
30 hours
101
TAF
9999 means:
Unrestricted visibility
102
TAF
Maximum Temp:
Minimum Temp:
TX (max)
| TN (min
103
The QNH in the TAF means:
Lowest pressure during that period
104
Hunting ________________ on the rotor blades
relieves stress
105
Advancing blade flaps up:
a. Induced flow ________
b. AOA _________
a. increases
| b. decreases
106
Retreating blade flaps down:
a. Induced flow ________
b. AOA _________
a. decreases
| b. increases
