Aircraft certified to operate above " must be designed so that occupants will not be exposed to cabin pressure altitudes in excess of after any probable failure condition in the pressurization system ".
22.
Just like on the flight computer, the ring is aligned with the air temperature and the pressure altitude, allowing the true airspeed ( TAS ) to be read at the needle.
23.
The conventional airspeed scale is calibrated in knots and the Mach scale is calibrated in percentage of Mach and connected to an aneroid that moves the scale to compensate for changes in pressure altitude.
24.
Flight levels are usually designated in writing as " FLxxx, " where " xxx " is a two or three-digit number indicating the pressure altitude in units of 100 feet.
25.
In radio communications, FL290 would be pronounced as " flight level two nine ( r ) zero . " The phrase " flight level " makes it clear that this refers to the standardized pressure altitude.
26.
In other words, density altitude is air density given as a height above mean sea level . " Density altitude " can also be considered to be the pressure altitude adjusted for non-standard temperature.
27.
The automatic controller normally maintains the proper cabin pressure altitude by constantly adjusting the outflow valve position so that the cabin altitude is as low as practical without exceeding the maximum pressure differential limit on the fuselage.
28.
To see the differences in the coding systems, consider a VFR aircraft with a VHF communication radio, VOR receiver with glideslope for ILS approaches, ADF, a GPS and a pressure altitude reporting transponder.
29.
In simple aircraft, without an air data computer or Machmeter, true airspeed can be calculated as a function of calibrated airspeed and local air density ( or static air temperature and pressure altitude which determine density ).
30.
The "'von Karman Gas Dynamics Facility "'at Arnold Engineering Development Complex, Arnold Air Force Base, Tennessee, provide aerothermal ground test simulations of hypersonic flight over a wide range of velocities and pressure altitudes.
