Human Factors (part 2.0)

Shel  Model

Merupakan suatu permodelan dalam membantu memahami Human Factors, dimana hal tersebut bisa distrukturkan / dijabarkan dengan baik dan benar. SHEL sendiri merupakan singkatan dari 4 hal , yaitu Sofware, Hardware, Environtment dan yang terakhir adalah Liveware.

Software : Prosedur Maintenance, Manual untuk Maintenance, checklist  dsb

Hardware: Peralatan test, struktur fisik dari pesawat, desain dari cockpit/ flightdeck

Environment : Lingkungan di Hanggar, kondisi di appron , dan lingkungan kerja seperti pola kerja,                             struktur manajemen , pendapat masyarakat terhadap industri terkait, dsb.

Liveware : Sebagai contoh orang / sekelompok orang yang terkait, termasuk Maintenance Engineer,                     Supervisor, Planner , Manager , dsb.

Kalau dilihat dari gambar di atas, Human Factors merupakan ilmu yang lebih mengkonsentrasikan pada Worker dengan elemen - elemen terkait pada SHEL Model. 

Aerodynamics Terminology

Aerodinamik adalah hal yang saya pelajari sewaktu saya masih bekerja di MRO.  Beberapa istilah / term ini merupakan sedikit dari berbagai macam istilah lain yang masih ada sangkut pautnya dengan ilmu lain di dunia penerbangan. Untuk istilah lain nanti saya update deh..hehe,,so enjoy reading,.

Static Pressure : Pressure which exertx a force on all bodies, acts equally in all directions.

Dynamic Pressure : The pressure on the surface of the body which  causes the moving air to stop

Streamline : a path traced out by a single particle of airflow such that this particle does not cross the                         path of any other

Stagnation :  At the leading edge of the wing, the air is brought completely rest.

Airspeed : the principle of the stagnation point is used in the measurement of airspeed

Equivalent Air Speed : The airspeed indicator reading  when corrected for compressibility at all                                                speed 

Indicator Air Speed : The Dynamic Pressure of air against a vehicle

True Air Speed:  The equivalent airspeed corrected for density 

Mach number : The ratio of TAS to the local speed of sound(LSS)

Mean Chamber Line : a line which joins the leading edge to the trailing edge .

Angle of attack: angle between the chord line of the wing and the direction of the relative airflow

Wash out : Decrease in wing angle of incidence from root to tip,

Wash in :  An increase in angle of incidence from root to tip

 Mean Chord : wing area divided by span

Taper Ratio : ratio of the root chord to tip chord

Aspect Ratio : The Ratio of the wing span to the mean chord, or alternatively span to wing area

Sweep Angle : The angle between the lateral axis and the Y. chord line.

Dihedral : The upward inclination of wing to the plane through the lateral axis

Anhedral : The downward  inclination of wing to the plane through the lateral axis

Aerodynamics part 1.0 Atmosphere

Atmosphere  : The gaseous envelope surrounding earth
aviation takes place around first 60k feet.

Gas composition : Nitrogen 78 % ; Oxigen 21 % ; Other gases 1%
Those proportions do not change with altitude.

Oxigen  : 1. for the sustenance of life
                 2. The combustion of materials.

Water vapour : 1. Responsible for weather around the earth ( turn affects aircraft operations and
                             performance
                         2. May cause icing of the airframe or engine which may impair an aircraft
                             performance

Region Atmosphere : 1. Troposphere : Temp. decreases  with an increase of height
                                                              (all significant weather occurs here)
                                   2. Tropopause : - Upper limit of tropopause    
                                                             - Temp. stops decreasing with an increase of height.
                                   3. Stratosphere : - From tropopause 50 km above sea level,                            
                                                              - Temp steady , increasing in height
                                   4.Thermosphere / Ionosphere : - Temp. increases with height/ altitude increases

Units 
1.Heat is transform of energi,
2.Boiling point of water : 100 C / 212 F / 373 K
3.Melting  point of water : 0 C/ 273 K

Convert temp :

F = (9/5)C + 32
C = (5/9)(F-32)

Temp Variation in the troposphere :
1. At Ground Level, Temp increases with a decrease of latitude
2. With increasing altitude,  temp will usually decrease with height up to the tropopause

Typical values of temp found at the tropopause :
Latitude             Temp (C)
equator               -80
45 N/S                -56
Poles                  -45

Lapse rates
The International Standard Atmosphere (ISA) value : 1,98 C / 1000 feet.

a reduction of density reduces lift.!!

Pressure :1. The force exerted on a unit area
                 2. In the atmosphere, pressure is caused by the mass of gaseous molecules acting under the                      force of gravity on a given area.

Pressure = Force / Area = (Mass x Acceleration) / Area

Units : 1 Newton = 105 dynes

Variation of Pressure in the atmosphere
At Sea Level :  Altitude (ft) = 0
                         Pressure in (mb)  = 1013.25;
                                       in (psi) = 14,7;
                                       in (Hg) = 29.92;
                                       in ( mm Hg)  = 760;

Pressure Altitude : 
The Altitude at which given pressure occurs in the international Standard Atmosphere

The cold air would have greater mass than the warm air due to the density difference. However it caused by the mass of overlying molecules on a unit area.

Density : Mass per unit volume of a substance

Density = Mass / Volume

at sea level : Density (kg/cu m)  = 1.225;

The reduction in pressure results in a lower density.

Humidity : the mass of water vapour in a given volume of air
Condensation : The phase change of a gas to liquid.
Freezing : the phase change of liquid water to ice